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Idling at 3000 rpm (he asks sheepishly)

Discussion in 'XJ Technical Chat' started by tygor, Jan 3, 2008.

  1. tygor

    tygor Member

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    Ok, I don't want to upset the forum... but I'm new (to riding, fixing, and the forum). I've searched and read many posts on carbs... TO THE QUESTION!!!

    Right now, my 83 Seca 750 idles at 3000 rpm (when warm). I don't like that.

    • Will it hurt my motorcycle if I ride it in this condition?
    • What simple things should I check before I, line-by-line, follow my Haynes manual on how to overhaul the carburetor?
    • and finally, I have a pessimistic co-worker who tells me to give up... carbs can't be cleaned to where they'll work right again. Please tell me otherwise.

    more info:
    I have a parts [sniff] bike (on which I was struck from behind) that has a working carburetor. While I fix Paul, I'll rob from Peter. If it matters, I'd still love to fix both bikes, so cleaning in within limits (though, again, I'm brand new to the whole thing).
     
  2. MBrew

    MBrew Member

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    It's ok to ride like that although you'll be a litle hard on the clutch. It won't be a crises though, I see people everyday who do worse things to a clutch.

    Try to set the idle down. On the 650's there is a thumb screw behind the carbs and between the two middle ones. It's easier to get to from the right side. Turn it counterclockwise to lower the idle. I ASSUME the 750 is similar.

    The carbs can be cleaned. It takes patience and a few supplies, Chacal has them all, and there are people on this board who are real experts at it. Chacal and Rick should be along at some point. I think they must have taken off for a couple of days, but they're great help.

    Good luck
     
  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    "take a couple of days off".....ha! I wish!!!

    Anyway, the easy things to check are the idle speed screw, as Mbrew suggests. Also, make sure that the throttle cable is not hung up a little, and not closing the throttles all the way.

    Also, make sure that the starter/choke is not partially stuck "on", or that the cable that controls it is not hung up or mis-adjusted.

    If none of that works, then you either have:

    a) a vacuum leak somewhere.
    b) an overly rich idle mixture screw setting(s).
    c) slide pistons that are not sliding fully shut
    d) God only knows what else.


    Rebuilding the carbs is fairly simple, and rebuilding the carbs CORRECTLY is just as simple and saves you time, money, and effort in the long run.

    Be aware that some XJ models used Mikuni carbs rather than the Hitachi's that are on your 750 Seca, and the two don't mix and cannot be interchanged. Other XJ models that used Hitachi's carbs (all XJ650 models except Turbo, and all XJ700 non-X models) can use those carbs, but the internal jetting will be different and needs to be swapped around.
     
  4. RickCoMatic

    RickCoMatic Well-Known Member

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    Chech to see that the Throttle Cable Tension Adjuster isn't what's making you run fast.

    Up at the Throttle Grib ... where the "Bend" in the Cable is ... there's a Knurl adjustment that can act just like an Idle Adjustment if it's too tight. Back it off so that you have a little bit of slack in the Cable.

    If that's not it ... and it's not THE Idle adjustment between under the middle two Carbs ... you have too much Fuel entering the Intake.

    Stuck Linkages
    Stuck Butterflys
    Stuck Diaphragm Pistons
    Too Rich a Pilot Mixture (Dark Plugs)
    Frayed Throttle Cable
    Weak Throttle Return Spring
    Air Leaks
    Cracked Manifolds
     
  5. RickCoMatic

    RickCoMatic Well-Known Member

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    Carbs can be Cleaned and Overhauled to be BETTER than they are when New.

    They are constructed of Cast Aluminum.
    The fittings and associated parts are Aluminum, Brass or Bronze.

    The only thing that "Gets Bad" is the Carb Top or Hat.
    They loose their shine and get pitted and either flake or rust.

    But the Tops have little to do with the Performance factors.
     
  6. tygor

    tygor Member

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    Ok, so let's pretend that some guy thought he had a carburetor problem since the bike idles at 3000 rpm. Then, this guy, warmed his bike up and turned the idle setting screw down until it idled at 1100 rpm. And he let it run for 15-20 min. while lubricating and polishing. If the bike idled well, does this fix the problem?

    Can harm be done riding a bike "with a problem", but hidden by an idle screw adjustment?

    The cable was not pinched. I witnessed slack when opening the throttle all the way (open, or closed? what do I mean?). Oiling the cable was beyond me for tonight since I didn't want to disconnect it. The cable didn't appear kinked or stuck. The spark plugs look normal (brownish contacts with a white insulator) though I only checked one.

    In the vast range of knowledge here in this wonderful forum... did I fix my problem?

    PS: Can "Fuel Injector & Carburetor Treatment" found in an auto store be safely run through a motorcycle (let's just say... if only half a bottle per tank was used)?
     
  7. MBrew

    MBrew Member

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    In all likely hood. If you have checked the mechanical throttle cable type of things that Rick suggested, you should be in good shape. Most of the other problems will manifest themselves in some other way after you made the change to the idle speed if they are there.

    Thats a very broad question that's loaded with liability concerns but if you have examined the throttle controls and found them to be in satisfactory condition, there is not much else there that would cause damage. The idle screw is there strangely enough to adjust the idle, so you are not really hiding anything.

    When you twist the throttle, the throttle valves open and when you release it they close. I generally just use WD40 on my cables and will spray a few shots at both ends, but mostly at the top and wipe off the excess. The problem with checking just one plug on a 4 carb engine is that you get 25% of the story. Every plug can be different. That being said the 1 change you made (idle adjustment) affected all cylinders, so if they were all a nice brown before and you checked one after, they all still should be good. Some shade of brown is what you want. Rick covers the nuances really well.

    In my opinion, probably. You said you let it idle for a while, I would like to see it go down the road before I say positively.

    All of them are different and will be used in different ratios. Read the label. Seafoam is a brand that is very popular in the motorcycle community. I'm generally not a fan of "mechanics in a can" but I have used it myself. I don't know that it did any good, but I certainly don't think it hurt anything.

    Good Luck,
     
  8. tygor

    tygor Member

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    After my alternator learning session last week, I am skeptical that this was fixed by the turning of a screw. For some reason (tell me is this is a common conception), I believe that the PO was negligent of regular care and intentionally "adjusted" things to make the bike salable. So, if he did bump up the idle screw to hide a carburetor problem... I don't know.

    But again, everyone... thanks for your help... and if you have more comments to help me (and if I still have a problem) please continue to offer advice.
     
  9. ZaGhost

    ZaGhost Member

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    My thoughts would be this...
    Take a nasty day you can't ride.... pull the carbs and do a full RickCoMatic style cleaning... Even if you're running better with an idle adjustment (and yes it can be that simple) it will run nicer after that.

    So dig up Rick's carb cleaning guide and follow that, and the crabs should go clunk guide and you're bike will thank you.

    I have Mikuni's on my XS, but between a good Mikuni guide and then following up with Rick's extra cleaning tips, my bike runs great.... on to fine tuning now...well in the spring (STUPID SNOW!!) .....

    My bike had sat for 7 years, with gas in the carbs... there was more crap in there than I could imagine, took a week long soak in carb cleaner to free up the float needles, so don't let anyone tell you dirty carbs can't be brought back to life

    Listen to Rick and Chacal and you will have a very happy Seca... :)
     
  10. IkeO

    IkeO Member

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    tygor i had this exact same thing happen to me when i bought my 750 seca. i turned the idle screw down after riding with it at 2500 rpms for like a month. (becuase i didnt know better) after i turned the idle down it ran fine and i love it. its not a big deal. some PO's that dont know alot have the idle that high because when the bike is cold and started up its at a good rpm. so they dont know better. but then as soon as it warms up boom it idles up to a high unhealthy number.

    look at this way.... the po sold you the bike. so the PO was probably not riding it. Which means he probably just started it for 10 minutes every month or so ( you could only hope) since it probably sat around alot it probably didnt run the best. so he turns up the idle to get it to run better. he probably never ran it long enough to get it really warm and in optimal conditions. my theory anyways. like i said this same thing happened to me.

    obviouslly now though you realize that when you start the bike up cold its going to be a much lower idle since you adjusted the screw. so just use the choke to compensate till it gets warm.

    in conclusion if your bike runs better now after doing that. then you have no problem. and its certainly not gonna be bad for you bike to ride it with the idle corrected. good luck.
     
  11. RickCoMatic

    RickCoMatic Well-Known Member

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    When a PO does "Something" to get a Bike running for a Buyer ... generally what ever gets done is to make the Engine run good enough to let the prospect hear the Engine run ... not too very much more.

    If you can pull the rack and clean one Carb at a time ... you'll have the knack-of-it by the time you get to the forth one.

    Cleaning the Emulsion Tube and Main AIR Passage goes a long way to getting the Bike running real good. That, plus flushing the Pilot Fuel and Air Passage will allow you to do some real fine tuning once the Pilot System is clean and providing the right amount of Fuel up to the top-side of the Carbs.

    The process is time consuming. But, the reward is great when the Carbs are cleaned of any foreign matter that would hinder full performance.

    When you acquire a Bike from someone who is selling it for some reason ... a Main reason is "Not running in Tip-Top Shape."
    You are an afternoon away from Cleaning-out the trouble that prevented the Bike from running good.

    Learning to Clean and adjust the Carbs is a GIANT Step in being able to have the most enjoyable experience your Bike can provide. Once the Carbs are squeaky Clean and you advance to tweaking them for performance ... you'll be glad that you know how Clean the Carbs are and that its just the fine-tuning you need to do ... not something that is going to haunt you all riding season long.
     
  12. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Yes, we will keep you on the straight and narrow.

    Rick and I diverge a bit on the carb-cleaning theory, not a matter of right and wrong, mind you, I just feel that if you're going to go to all the time and trouble to remove and "rebuild" the carbs (which solves about 95% of all the performance problems with the bikes, PLUS sets a proper baseline for solving any other problems that might exist), then take the extra time (maybe 30-45 minutes extra out of a total of the 8-10 HOURS you're going to spend on this project) and the extra money (maybe an extra $25-50) to REALLY do it right.....and break the rack apart (mechanically, not very hard, just another 16 screws) and replace the 25+ year old throttle shaft seals (trust me, unless it's been done before, they're junk).

    Taking the rack apart requires no extra tools, and only requires you to take some extra care BEFORE you take the first screwdriver to the rack to notice how/where many of the brackets, etc. are positioned and oriented. You'll need a small, flat piece of glass or some other perfectly flat surface to set the carb throats down onto before re-bolting the upper and lower rack brackets on (to keep the carbs in absolute alignment with each other). And you'll want/probably need to replace the throttle shaft butterfly retaining screws, as the original ones can get their tiny little screw heads all buggered up during removal.

    By the way, almost every screw on these bikes are "JIS" standard/design screws, JIS standing for Japanese Industrial Standards, and both the depth and design on the phillips-head "slot" is different than typical US slots. In a nutshell, JIS screws (which can be easily identified by the small punched single "dot" on the screw head, in between two of the screw slots) have both deeper and "squarer" slots and thus can hold more torque than their rest-of-the-world counterparts. They also require a JIS screwdriver to take full advantage of, and to prevent rounding out the slots as typical phillips-slot screwdrivers will do. The more "rounded" edges of a standard phillips-head screwdriver cannot exert as much torque on the screw head (by design, actually) and will slide out of the slot, taking some of the slot material with it unfortunately!

    So it might be a good idea to also invest in a set of quality JIS screwdrivers, trust me, they make a difference (yes, they can be used on standard phillips head screws, too):

    HCP5904 JIS Standards SCREWDRIVER SET. Japanese phillips drive screws have sharper corners than regular phillips screwdrivers so they won't turn out under heavy torque. In order to take advantage of this feature, and to avoid stripping out the JIS screw heads by using US-standard phillips screwdrivers, it's a good idea to invest in a set of quality JIS-standard screwdrivers. This set of 4 contains one each of #1, #2, #3, and #4 sized-tip screwdrivers, and this range of sizes will handle everything down to an M3 sized screw (that's tiny, like the size of the petcock faceplate mounting screws) all the way up to screws bigger than anything I've seen used on these bikes. They all feature sturdy plastic handles, and come in a handy vinyl storage pouch.
    $ 34.00

    Okay, the following post will give you a list of my thoughts regarding proper carb rebuilding procedures and some things to watch out for if you've never attempted to do this before, or---if you're like me----have worked your entire life on automotive carbs and thus expect these carbs to be similar (which of course they are, they're carbs after all, but auto carbs have passages the size of canyons compared to these carbs, and thus the internal "cleaning" process takes on a sense of urgency and importance an order of magnitude greater than what you might expect).

    Do it once, do it right, and you're life will be good. Do it wrong the first time, and, well, I always suppose there's time to do it right again later.......
     
  13. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    INITIAL THOUGHTS:

    a) If you don't plan on checking and correcting (if needed) the valve shim clearances, don't bother cleaning and rebuilding the carbs.

    b) If you don't plan on synching the carbs when you're done, don't bother cleaning and rebuilding them.

    c) If you don't plan on using a colortune plug to tune the carbs when you're done, don't bother cleaning and rebuilding them.

    d) You will never, Ever find anyone who is willing to do as thorough a job in cleaning your carbs as you are.

    e) Probably a good 50% of the posts on this forum revolve around the subject of "My bike doesn't run right." or "idle correctly" or "it won't start when cold" or "it idles fast" or .......well, you get the picture. Almost all of these issues are carb-related issues, and their causes, although many and varied, all boil down to one thing:

    Your carbs are out of adjustment, dirty, or a combination of the above.

    That's actually the good news! Because you've isolated the problem down to one specific component.

    That's also the bad news. Because a proper rebuild and re-tuning of these carbs, while not mechanically difficult, can hold quite a few surprises for the un-experienced, the un-wary, the lazy or sloppy rebuilder, etc.

    My basic understanding and theory in regards to carb rebuilding (or any other project, for that matter) is this:

    Do it once, completely, thoroughly, and correctly.

    That's how you save yourself money, time, frustration, and aggravation.

    To that end, I offer you this short sermon titled CARB RACK GOTCH-YA'S in order to make your carb rebuilding experience easier, by making you more fully prepared to tackle the task at hand.

    Many people claim that dis-assembling the carbs from the rack during the rebuild process is NOT necessary. Although that statement may be true in a few specific instances, it is my opinion that such a course of action is "false economy"---in return for less effort now, you're going to be sitting on a ticking time-bomb of future problems just waiting to happen, and waiting to be mis-diagnosed ("hey, I already cleaned the carbs and still have these problems, what now?"), and thus additional time & expense.

    My experience has led me to the conclusion that not fully rebuilding these somewhat finicky carb sets while you have them off the bike----and lets face it, the removal and re-install process is one of the most time-consuming and tricky parts of the whole process, and has to occur no matter how much or how little "rebuilding" goes into the carbs while they're off the bike!----is not the correct way to proceed.

    So please, consider doing a Full and Complete Carb Rebuild procedure when you have the time. Given the age of the bikes, the lack of attention that the previous owner paid to them, and the sloppy level of work that dealership service departments do (and have done over the years past)----give your carbs the proper attention that they deserve. You'll learn alot, you'll solve most of the carb related problems with these bikes, and you'll have the pride, knowledge, and experience of having done it yourself.

    And your carbs will thank you.........

    NOTE: this guide is written specifically with the Hitachi HSC32/33 series carbs in mind, and certain specific aspects will not apply to the Mikuni series of carbs used on XJ550, XJ650 Turbo, XJ700-X, XJ900, and XJ1100 models. Generally, though, the same thoughts apply.


    BEFORE YOU BEGIN:

    Have all parts and supplies you can even imagine/consider replacing already ordered and received.

    - At the end of this guide there is a semi-complete list of parts that you'll need, besides any that you discover to be missing, damaged, or unusable.

    Have ALL of the tools, special or common, that you'll need. Stopping and starting not only wastes time and effort and is frustrating, but it leads to confusion or shortcuts, both of which are 4-letter words in the carb-rebuilding biz....

    - At the end of this guide there is a semi-complete list of tools that you'll need.

    Obtain (beg, borrow, or steal) a Factory Service Manual and/or an aftermarket Haynes or Clymer Owners Workshop Manual and read through it before you begin. Try to make sense of the pictures and procedures IN YOUR MIND before you even remove the carbs.

    Especially if this is the first time you've attempted a carb rebuild, this "pre-learning" will most likely be invaluable training for you.

    Have a pad of paper and a pencil and take at LEAST 5 pages of notes and sketches diagrams. That's five 8-1/2" x 11" pages. If you don't fill up five pages, you have either:

    a) done this at least 10 times before, or.....
    b) you're going to hate yourself in about 2 days time.

    Better yet, have a digital camera and a friend available for at least the entire 2 hours carb rack removal and dis-assembly steps. Count on taking at least 100 pictures.

    Best practice: have a video camera and film the whole thing.

    Think I'm joking? I'll place 10-to-1 odds that you'll be cursing like a drunken sailor AND THROWING THINGS within 36 hours if you DON'T take the above advice!

    NOTE: the following is NOT a complete, step-by-step guide to dis-assembly and re-assembly of your carbs! It is intended to be a "helpful assistant" guide to prevent you from making mistakes of the type that you will most likely make your first time in attempting this project! The complete step-by-step procedures can be found in other posts in these forums and in the factory and aftermarket service manuals. I would especially take the time to read, re-read, and print out a copy of RickOMatic's carb-cleaning step-by-step instructions (and his many other works on this topic) as his information, experience, and know-how are NOT to be ignored!



    DIS-ASSEMBLY:

    NOTE: the #1 carb is the left-most carb, as you're sitting on the bike (clutch lever side of the bike). #4 carb is the right-most carb (brake lever side of the bike).

    Carb bodies...mark them 1, 2, 3, 4, with an engraving pen or a point punch, they're all different.

    Mark the throttle arms with an engraving pen 1, 2, 3, 4....there are three different ones.

    Mark the throttle arm end brackets with an engraving pen 1, 2, 3, 4.......there are three different ones.

    Butterflies....mark them, 1, 2, 3, 4 on the side facing the airbox with an engraving pen. Scribe an arrow so that you'll know which way is pointing up or down (doesn't matter which, as long as you're consistent) so that the butterflies can go back into their proper carbs, and oriented the same way they came out. If you don't get this right, expect big troubles later!

    Carb bowls, there are LH (#1 or #2) and RH (#3 or #4) bowls. No need to number them, as it is obvious which is which, but just remember which are which when doing re-assembly.

    Mark one end and write it down (#1 end or #4 end) of the starter circuit rod (use a small saw mark or point punch one end).

    Throttle return springs....mark them or bag them individually, there's 3 different ones. Note where/how the spring end hooks are oriented in relation to the throttle arms and the carb body retaining tangs before taking them off the carbs!

    Brackets/clips on carb hats....make a diagram of which one goes where, and how it is oriented when installed.

    Carb hat screws.....there are different lengths in different positions. All positions that have a clip or bracket use the longer screws.

    Note position of "which-jet-where":

    LOWER END: Main FUEL jet uses the copper washer underneath, and is the higher numbered (larger opening) jet. Also check to make sure that all of the jets are of the correct and same size. The jet size is stamped into the top face "rim" of the jet:

    MAIN FUEL JETS:

    #106 is used on 1984 XJ750 Seca models.
    #107 is used on all XJ700 non-X models.
    #110 is used on all XJ650 models (except Turbo, except European).
    #112 is used on all XJ650 European models.
    #120 is used on all other XJ750 models.

    PILOT FUEL JETS:

    #36.5 is used on all XJ700 non-X models.
    #40 is used on all XJ650 (except Turbo) models, and all XJ750 models.
    #43 is used on XJ750 European/UK models, per Haynes manual.


    UPPER END: Main & Pilot AIR JETS are the same size bores up top. The main air jet is in the "center" hole and is the lower numbered (smaller opening) jet. The pilot air jet is in the hole closest to the "front" of the carbs, front meaning nearest the cylinder head. The rearmost hole is for the cover plate hold-down screw, if so equipped (some model carbs did not use the cover plate nor the hold-down screw). The Haynes shop manual for these bikes has the positions of the main and pilot AIR jets reversed in their photograph on page 123, picture 7.9b.......

    MAIN AIR JETS:

    #50 is used on all XJ650 models (except Turbo).
    #70 is used on all XJ700 non-X models and 1984 XJ750 Seca.
    #80 is used on all other XJ750 models.

    PILOT AIR JETS:

    #195 is used on 1980-81 all XJ650 models, 1982 XJ650 Seca, and XJ650 European models.
    #205 is used on 1982-83 XJ650 Maxim models.
    #210 is used on XJ700 non-X models.
    #225 is used on XJ750 models.


    NOTE: air compensator jets----on each side of the carb throat, facing the airbox----are always a #36 size for those models using them. Some models, such as XJ700 non-X models, do not use air compensator jets.


    Butterfly-to-throttle shaft retaining screws......they're self locking and the heads strip easily.

    All other---every last one----bolts, screws, and nuts: they're not self locking, but they strip even easier.

    Use HEAT and COLD to try to remove frozen fasteners rather than force. Penetrating oil works better if the part is heated. The differential expansion coefficients (hey, how's that for smarts?) of dissimilar material, seized-together metal parts is a natural law of God and the Universe and is free to everyone. By HEAT, we mean a heat gun or a pencil tip torch, used carefully (less is more). By COLD, we mean like 2-3 hours in the freezer or immersed in ice water.


    INSPECTION/CLEANING:

    Check the long, skinny jet needle to make sure it hasn't retracted from it's plastic top holder. Also check the very end of the tip for scratches, gouges, or deformation ("mushrooming") of the very bottom, pointed tip.

    Also check to make sure that all of the needles are of the correct and same size. The needle size is stamped into the needle barrel just below the plastic top holder:

    Y-10 Needle is used on XJ650 Maxim, Midnight Maxim, and Seca models.
    Y-11 Needle is used on European XJ650 models.
    Y-13 Needle is used on all XJ750 models.
    Y-14 Needle is used on 1983 XJ750 Maxim models (this might not be correct for US models).
    Y-18 Needle is used on 1984 XJ750RJ model.
    Y-20 Needle is used on all XJ700 non-X models (with Hitachi carbs).

    Check piston rubber diaphram for even the tiniest of air holes or tears. Hold it up to a strong light and if you can see light (pin holes) in the diaphram, it's toast. If any are located, replace the piston unit.

    Clean the emulsion tubes thoroughly. This means inside and out, and every one of those tiny little holes along the bore must be completely clean, and whatever you do, DON'T ENLARGE THE SIZE OF THOSE BORE HOLES WHEN CLEANING THEM!

    Remove every piece of rubber diaphram or o-ring and gasket material before soaking in carb dip, as it will eat them up and make a gunky mess of things.

    Clean all passages, both in the component parts and in the carb and bowl bodies, thoroughly: overnight carb dip, then ultrasonic, then wire brushes of various sizes and metal wire probes, then spray cleaners, then compressed air, then do it with spray and compressed air over and over again until you're DAMNED CERTAIN THAT THE PASSAGE IS CLEAN. Then it wouldn't hurt to do it once or twice more, just to be sure.

    How to be sure? If compressed carb cleaner blown into a passage does not exit the other end of the passageway FREELY and FORCEFULLY, it ain't clean.

    Clean the carb bowl starter jet and pickup tube thoroughly: overnight carb dip, then ultrasonic, then wire brushes of various sizes and metal wire probes, then spray cleaners, then compressed air, then do it spray and compressed air over and over again until you're DAMNED CERTAIN THAT THIS PASSAGE IS CLEAN. Then it wouldn't hurt to do it once or twice more, just to be sure. How do you know when your starter jet is really, truly, zestfully clean? One of two ways, and I recommend using BOTH:

    a) shine a strong penlight or mini flashlight into the bottom of the bowl, where this jet passage "intake" is located. Look through the top of the bowl down into the jet passage "outflow" passage (this is the passage that the brass suction tube in the bottom of the carb body actually fits down into). Focus your eye carefully on the jet opening and make sure it's clean. P.S. it helps to do all this while in a darkened area....

    b) put the spray tip (you may have to gently shape the end of it to a fine point) of a can of carb or brake cleaner into the intake opening of the starter jet and let rip a spray. A STEADY, FINE, POWERFUL STREAM OF FLUID WILL COME OUT OF THE OUTFLOW PASSAGE ON THE TOP OF THE CARB BOWL IF THE JET IS PERFECTLY CLEAN AND OPEN. I mean this stream will absolutely spit out a good 5-10 feet. If the stream isn't powerful and laser-like precise coming out of the jet, then the jet isn't zestfully clean.....

    BTW, when using the spray-stream method of checking the jet, don't even THINK of putting your eye or face anywhere even NEAR the jet outflow path, unless you'd like a painful and potentially serious trip to the emergency room.

    GENTLY polish the brass slide piston and it's bore in the carb with 400/600/then 800 or 1000 grit sandpaper until it's smooth as a babies bottom. KEEP YOUR SANDPAPER WET WITH WD40 (etc.) WHILE POLISHING!!

    You probably think I'm being anal---and you could have a point there---but you'll feel like kicking your own butt if you go to all this work, put the carbs back together, and then discover that it still doesn't run correctly because they're still dirty/clogged inside.


    OPTIONS FOR BOWLS AND BODIES BEFORE FINAL SPRAY/AIR CLEANING:

    The carb bodies are an aluminum alloy, while the carb bowls (most of them) seem to be a more pure aluminum. Carb dip and ultrasonic cleaner solutions may "stain" these metals and make it a dark grey color, perhaps even with some runny, ruddy "streaking". If you want them to look like new, here's what you do:

    a) glass bead blast them. This is has the unpleasant side-effect of REALLY clogging up all the tiny passages, so an unbelievably thorough cleaning is necessary afterwards. Better to plug up all the internal passages (screw a carb hat on top, and a bowl onto the bottom, and tape/plug up as many internal access openings as possible before doing this). However, they will be REALLY bright once done, and with a velvety finish.

    NOTE: do the carb dip and ultrasonic cleaning BEFORE you blast them, or they'll just turn dark grey again!

    After blasting, you'll be cleaning the carbs with carb or brake cleaner and compressed air ONLY, in order to prevent staining them again.

    b) metal shot tumble the bodies. In an industrial tumbler. Not a home version that you buy at Harbor Freight for $49.95. It will take 45 days of tumbling per carb body to do it that way. Find an industrial metal processing place in your town (or send them to me) and have them tumbled with the proper size metal shot and they'll come out looking almost like they've been chrome-plated after about an hour. Price vary, I get a complete set done for about $95 down here, less if multiple sets are done at the same time. P.S. by "industrial" I mean one that's about 12 feet in diameter and uses 440V 3-phase electrical service to run, and shakes the whole 10,000 square-foot warehouse room that it's in.

    P.S.S. I have custom-made passage block-off plates and rubber plugs of the appropriate sizes inserted into all screw and passage holes before tumbling, so that no metal shot can get up into such passages or holes, cause if they do, you'll basically never get them out, and you will hate yourself forever for allowing such a mistake to occur.

    NOTE: do the carb dip and ultrasonic cleaning BEFORE you tumble them, or they'll just turn dark grey again!

    If you want to PROTECT your blasted or tumbled carbs afterwards, use some fuel-resistant clear coat. Allow for three coats with dry time in-between. So plan on a day of spray time.

    If you're going this far, you might as well re-plate or powdercoat your chrome carb hats. And re-plate or spray "gold cad" paint on your brackets, throttle arm levers, etc. Zinc cad (silver) spray works great on upper and lower rack bars, starter circuit finger levers, etc.

    If you do all of the above your carbs will look so great upon re-assembly that you will probably want to go to an art supply store and get a shadow box and permanently mount them in there and display them on your mantle, etc. You can then buy another set of used carbs off eBay and rebuild them for daily use on your bike..........


    RE-ASSEMBLY:


    Rule #1: Never, EVER rush.

    Use anti-seize on all bolts during re-assembly, except for upper and lower rack bolts, which use permatex semi-permanent (purple) thread locking compound.

    Use anti-seize on all bolts, screws, etc. during re-assembly.

    Use anti-seize on all bolts, screws, etc. during re-assembly.

    USE ANTI-SEIZE ON ALL BOLTS, SCREWS, ETC. DURING RE-ASSEMBLY.

    USE ANTI-SEIZE ON ALL BOLTS, SCREWS, ETC. DURING RE-ASSEMBLY.

    USE ANTI-SEIZE ON ALL BOLTS, SCREWS, ETC. DURING RE-ASSEMBLY.

    Anti-seize compound was invented by one of the minor yet powerful ancient Gods, and if you don't use it during re-assembly on everything (except as noted above), you will be cursed by this God ruthlessly and forever.

    Use 100% silicone grease (NEVER, EVER PETROLEUM-BASED GREASE) to lubricate o-rings and hold the slide piston diaphram in place during re-assembly.

    Do not over-torque anything.

    One of the most important parts of reassembly:

    When reinstalling the butterflies, hold the carb up to light and look through it. The mounting holes are slotted ever-so-slightly so that the butterfly position can be fine-tuned. Assemble with the screws very lightly tightened, hold the carb up to the light so you are looking through the throat. Adjust the butterfly so it makes a light-proof seal all the way around it's circumference in the throat.

    If you can see light, then air will leak past at idle AND the the butterfly will probably bind in the throat when things get up to operating temperature. It cannot be stressed enough that the butterfly must seat fully when allowed to close gently under spring pressure without any additional force. (note: if in the bank, the #3 carb must have the idle stop screw fully backed off so it does not prevent closing).

    Tighten the screws fully and recheck to make sure they didn't move!

    Make sure you "bench-synch" the carbs after re-assembly.

    When it comes time to set the float levels, get all the proper tools and fixtures ready, and then invite someone who knows how to do it to come over and let them do it. It's not rocket science, but it sure is a messy, pain-in-the-butt, trial-and-error procedure!


    CARB FASTENER TORQUE VALUES:

    NOTE: upper & lower rack screws and butterfly-to-throttle shaft retaining screws use semi-permanent loctite; all others use anti-seize.

    HOWEVER:

    a) make sure anti-seize compoind doesn't get into a passage where it will undo all your careful attention to cleanliness, and....

    b) disregard the torque specifications of the fasteners. I draw your attention to Yamaha's standard passage regarding torque specs (included in every Yamaha service manual):

    "Unless otherwise specified, torque specifications call for clean, dry threads. Components should be at room temperature."

    If the spec is for lubed threads (and anti-seize grease is a lube) on a particular bolt, then the Yamaha torque chart will have a little oil can symbol beside it.

    c) Therefore, applying full (dry spec) torque to a lubed bolt may well strip the expensive casting or brass jet. As a rule of thumb, reduce the specified torque by at least 10% if you have applied anti-seize compound to the threads of the bolt.


    Hat Screws:
    none given, so use common sense and be gentle

    Plastic slide piston needle retaining nut:
    none given, so use common sense and be gentle

    Enrichment circuit brass fitting:
    40 ft-lbs (???---that's what the manual states, but it sure seems excessive!)

    Float seat:
    22 ft-lbs (???---that's what the manual states, but it sure seems excessive!)

    Jets:

    Pilot fuel jet:
    3.5 - 4.5 ft-lbs.

    Main fuel jet:
    3.5 - 4.5 ft-lbs.

    Air compensator jets:
    4.5 ft-lbs

    Pilot air:
    4.5 ft-lbs

    Main air:
    4.5 ft-lbs

    Air jet cover plate mtg:
    none given, so use common sense and be gentle

    Upper rack mtg.
    3.5 - 4.5 ft-lbs.

    Lower rack mtg.
    4.5 ft-lbs

    Bowl-to-carb:
    3.5 - 4.5 ft-lbs.

    Bowl drain screw:
    4.5 ft-lbs

    Throttle shaft nuts:
    none given, so use common sense and be gentle

    Fuel Tank:

    Petcock mounting screws to tank:
    4.5 ft-lbs

    Gas cap mounting screw to tank:
    3.5 - 4.5 ft-lbs.

    Sender unit to tank:
    4.5 ft-lbs

    Tank emblem screw:
    none given, so use common sense and be gentle


    Tools needed:

    * idle jet screwdrivers.
    * 100% silicone grease. any other type of grease will attack rubber.
    * anti-seize compound
    * semi-permanent (purple) Permatex thread locker compound.
    * brake or carb cleaner (and lots of it).
    * carb dip or access to it.
    * wire brushes, various sizes.
    * brass & steel wire toothbrushes
    * mini/man sized passage cleaning set
    * Flat & phillips head screwdrivers, various sizes. GOOD QUALITY flat blade and phillips head. DO NOT TRY TO USE THE WRONG SIZE SCREWDRIVERS, THAT'S A RECIPE FOR FAILURE, TIME DELAY, AND ADDITIONAL EXPENSES!
    * Engraving pen or punch to mark carb bodies, bowls, throttle shafts, etc. Ink won't do, even "sharpie" style permanent ink markers, since carb dip and spray cleaners will remove them.
    * Fine sandpaper, automotive paint grade, 400, 600, 800, 1000 grit.
    * Hammer.
    * METRIC open-end wrench and socket assortment
    * pry bar or soft mallet.
    * channel locks, vise grips, pliers---needlenose and otherwise.
    * dental picks.
    * flashlight.
    * magnifying glasses.
    * time.
    * paper/notebook
    * ZIP LOCK BAGGIES OF VARIOUS SIZES.
    * pen.
    * a clean, semi-uncluttered, well-lit and ventilated area to work in.
    * digi-cam.
    * haynes manual.
    * yamaha service manual
    * xjbikes.com threads already bookmarked.
    * paper towels/shop rags
    * access to ultrasonic cleaner
    * access to tumbler or glass-bead blaster.
    * resto paints/coatings, if you are so inclined to do detailing.
    * mini drill bits for carb bowl starter jet cleaning.
    * e-z outs and/or LH drill bits
    * small pencil torch and/or heat gun
    * vise
    * drill & drill bits
    * patience
    * synch sticks/tool
    * YICS block-off tool, if your bike is has a YICS passage.
    * YICS port passage cleaning tool, if your bike is has a YICS passage.
    * gun brushes or similar
    * gun cleaner or similar
    * colortune plug
    * a flat piece of glass, maybe 12" x 24", that you can set the carb rack onto (throats down onto the glass) as you re-assemble the individual carbs together and tighten the upper and lower rack bar screws. A piece of FLAT marble or smooth tile will work, also. It had better be perfectly flat though! The four carbs must be placed on a perfectly flat surface as the screws are tightened or mis-alignment will occur, and life gets really un-fun after that occurs.........

    Here is another thread that contains some better, more detailed info about carb rack assembly "alignment" procedures, since the factory service manual and Haynes manual cover these issues very briefly and without much info.....part of the reason why people are uneasy about doing the whole "break the rack" process. In reality, "aligning the rack" is pretty simple:

    http://www.xjbikes.com/Forums/viewtopic ... html#63236



    Parts needed, at a minimum:

    * throttle shaft v-seals.
    * float needle seat rebuild kit (seat, needle, clip, seat washer).
    * bowl gaskets.
    * idle mix washers & o-rings.
    * carb bowl drain screws.
    * new/replacement carb hardware (screws, etc.)---now is the time to upgrade to stainless steel and/or allen-head fasteners if so desired!



    Valve shim replacement parts/tools needed:

    For all except the XJ700X/750X models---they're a whole different animal!

    * shims as needed/determined.
    * shim bucket tool.
    * feeler gauges, range of .002" - .012" (inches!)
    * 19mm open end wrench.
    * telescoping magnet.
    * small flat-bladed screwdriver or pointed pick tool.
    * valve cover gasket/end caps seals as needed.
    * glue for valve cover gasket.
    * new washers (at least, or bolts and washers) for the valve covers.
    * crankcase cover gasket.
    * a decent set of calipers or a micrometer is useful to have for checking the REAL valve shim thickness.



    FINAL THOUGHTS:


    a) If you don't plan on checking and correcting (if needed) the valve shim clearances, don't bother cleaning and rebuilding the carbs.

    b) If you don't plan on synching the carbs when you're done, don't bother cleaning and rebuilding them.

    c) If you don't plan on using a colortune plug to tune the carbs when you're done, don't bother cleaning and rebuilding them.

    d) You will never, Ever find anyone who is willing to do as thorough a job in cleaning your carbs as you are.
     
  14. RickCoMatic

    RickCoMatic Well-Known Member

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    Therein is the difference between "Cleaning" and "Overhauling"

    Some Carbs only need to be Cleaned. You get "The Eye" for those after some time handling Carbs and you also "Get a feel" for how deep you need to go to Clean a rack of Carbs.

    Overhauling a Complete rack, taking-out the Butterflys and doing Shaft Seals might be a little ... "Out of reach" ... for the Novice Do-it-yourselfer.
    There is a good deal further to go Overhauling a rack than if you just do a thorough Cleaning.

    Once you separate the individual bodies and get right down to the nitty-gritty of stripping the rack clean; you need the experience of ... at least ... seeing it done once before heading down that road all alone.

    If this was a Classroom and the students could come forward to see what the Seals look like and how they are seated ... I wouldn't have the reservations about having people continue and do The Full Monte!

    But, I know, after doing a few sets of those Shaft Seals, that there are a few pitfalls that seem to catch you when you least expect it. And having to go back and re-do what seemed right the first time leaves you open for doing more harm than good if you ... if you ... > Don't have the right tool, the manual dexterity and the presence of mind to keep everything aligned, straight and free moving.

    I laud those who will do a replacement of the Butteryfly Shaft Seals to COMPLETELY Overhaul a set of Carbs.

    My opinion, for those who don't have the experience in removing Carb Butterfly Shaft Seals is:

    Buy a set of Parts Carbs and take as long as it takes you to go beyond a routine cleaning and strip the set down to bare castings.

    The Parts Carbs will be forgiving.
    Your Bike's Carbs will depend on you being perfect the first time.
    The first time I did them ...

    I was less than perfect and needed to do some backtracking.
    Backtracking too many times will make things go bad.
     
  15. schmuckaholic

    schmuckaholic Well-Known Member

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    All valid points, Rick. Some of us, however, don't have the luxury of seeing it done first before needing or wanting to do it ourselves. Unless you happen to have documented the process on video...?

    The good news is, I do have a spare set of carbs I bought for the express purpose of practicing on first.
     
  16. IkeO

    IkeO Member

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    the single most important thing i ever did to give me enough courage to start doing carb work was opening up a spare set of carbs. and they wernt even from an xj. they were a honda 550. but opening them and going ok this must do this and this must do that. it all started clicking. since then ive gotten 4 dead bikes running by cleaning the carbs.

    so definatly a spare set is the way to go. at least i think. better than any video or pictures. (as much as i wanted to see them too; theres some good ones on youtube)

    working on your one and "only" set of carbs seems so intimidating. i dont think i ever would have done it without studying the spare.
     
  17. RickCoMatic

    RickCoMatic Well-Known Member

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    There you go ...

    Mark everything to go back exactly wheere it came from ... especially the screws that secure the Butterflys to the Shaft.
    Use Permanent Locktite when you put the Butterflys back on the Shaft.

    The Shaft sometime withdraws with the Seal as the Seal catches on the Flat of the Butterfly cut-out. Don't lose it and pull the Shaft rotating it left and right if it resists coming out ... that way you won't rip the Shaft Seal taking-out the Shaft.
     
  18. schmuckaholic

    schmuckaholic Well-Known Member

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    Spent some quality time with the parts carbs tonight. It is, indeed, not that difficult to pull the whole thing apart. Rather straightforward, actually. Took lots of pictures. (Maybe I'll try and make a writeup out of this.) Since I had a Canon 5 megapixel camera fall into my lap (my benefactor upgraded to a Kodak 7.1 with 10x optical zoom), my 1.3 megapixel workhorse just got retired.

    Tomorrow: I start pulling butterflies. Glory!
     
  19. Robert

    Robert Active Member

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    Go for the throat! Guts and determination = Glory!
    Rip it up and let's see your photos!
     
  20. RickCoMatic

    RickCoMatic Well-Known Member

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    Ah kin feels howz yeh gots duh goot Mo-Jo woikin'

    Take it slow and deliberately.
    Your Master Carb Overhauling Merit Badge is waiting.
     

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