Already run out of ideas and loosing confidence on the bike.

Hi guys, I need serious help here, like I said I'm out of ideas. I own a 1985 xj700n, a month ago I took her to the shop, the guy there took the carbs apart, clean everything, change the jets size back to spec, sinc the cabs and everything you need to do and I don't know how. We ran into a problem with the carburators boots, it seems they are not the one for this bike, anyway he putted everything back got her running very good but with a vacum leak due the boots. In low she take a little to take of, but at high speed she's running like a dream. Winter time is almost here and I have the bike sitting for 4 days in my living room (very cold outside) with the battery disconected. Today I conected the battery fire up the bike and she was good, ride for about 100 meters at less than 20mph, and she started to sound like running in 3 or 2 cilinders, back at home checked the mufflers from the cilinder and one was not as hot as the other, spark plug black as carbon replace it and she is running good again so I take her to the road and about 5 miles later start to sputtering like running out of gas, stoped check the spark plugs 3 of the 4 were black again, clean them replace one of them with the only new I had in the tool kit and went back home with the bike sputtering al the way back. This is NOT the first time it happens, but is the first time it happens in about 5 miles. Now this is what I did when I got home. Checked for spark (cil.4 does not have any) change the spark and it works, clean the other spark plugs until I get the new from the shop now she's running good but I'm not so confident to take her for the long ride. What I can start doing from scratch??? I'm pretty sure carbs are ok...I installed an used ignition coil for 1 and 4 cil. when the carbs were out of the bike...so I don't know what or where to look now....Thanks

 

Check the TCI - another thread like this

 

I suspect you still have carb issues, float levels too high or not shutting off. Your plugs are black that means there is too much fuel either from floats or jetting. Did they wet set float levels while the carbs were out?

 

Definitely carb issue. You are flooding the engine. Plugs get ruined when they get soaked by gas. That would fit your symptom: Replace plugs -> runs fine short distance -> plugs are soaked and stop working.

 

Do you still have the non-original boots? There's a bit of mysterious magic with these boots, it's rather important to have the correct ones. It will definitely affect air flow and mixture, and could be related to your obvious mixture issue.

It's probably not the only issue, but... Not to be taken lightly, from what I read.

 

Re: Already run out of ideas and loosing confidence on the b

We've seen this happen with brand new NGKs for 6-8 years now but not with any other major brands. For "entry-level" conventional spark plugs we normally use Autolites. At the other end of the spectrum, Denso Iridiums are "the shit" as they say, IMO.

 

That's no reason not to use NGK's. If you don't saturate them, they last a good long time.

Back to the original problem: DO YOU WANT A SOLUTION, or do you want to get more frustrated than you already are?

Honest answer: you trusted a shop; they didn't get it right.

Not the first time.

You need to do the following to fix the problem once and for all:

-Get the proper intake boots (or verify that what you have on there are indeed correct, from the sound of it they may be but anything is possible.)

-Remove the carbs, and while they're off, do the following:

>get your valves in spec.
>do a compression test.
>go through the carbs yourself; be sure they're truly clean and correctly assembled.
>"wet set" the float levels.
>do a good solid bench sync.

-Return the carbs to the bike, and do a running vacuum sync. (With YICS blocked if you have a YICS motor.)

In order, and don't leave anything out.

Or you can fight with it some more. Your choice. The shop ain't gonna ever get it right.

 

Re: Already run out of ideas and loosing confidence on the b

Well, we're going to have to agree to disagree on the NGK situation. Just fixed a little Polaris 90 a few minutes ago with exactly the same problem. Why pay the same price for an inferior product??? NGKs were excellent plugs back in the 70s, the very best around IMO, but not now.

Do you own NGK stock??

 

They perform a whole lot better than Champions in my Norton; and I use a couple of sets a season in the 550s because the ground straps erode after about 3K miles; but they also only cost $1.99 at AutoZone.

And they're fine if you can manage to not flood the bike.

I use them because they're one of the two plugs recommended by Yamaha for my bikes, and I can't find the other one (ND) easily or I might try those.

 

Re: Already run out of ideas and loosing confidence on the b

I can't vouch for the conventional Densos, just the Iridiums. They are top notch. A buddy of mine here in Athens, AL who is the crew chief for Team Hammer turned me on to them several years ago.

 

GRRR. Now I'm going to have to track down a couple sets of ND X24ES-U's and compare them.

They're considerably more expensive at first glance; we'll have to see if they're worth it.

 

First ...Thanks to all...I'll like to make a separation here about this problems...1- The boots are not the ones for the bike wich cause a vacuum leak at less than 2000rpms, only way to fix it is to get the correct set of boots.
2. The carbs problems... I agree I trusted to the shop and the guy didn't do a good job, he WAS a kind of a friend of mine, I trusted him because he works with bikes and he made his own chopper out of a 1982 Kawasaki LTD 1100, also 4 cil. in line...I was expecting another kind of job, like more professional maybe...In addition to all this, parts are more than a few and far apart in this part of the globe for this bike or any big bike from the '80s or '90s. In Argentina we are suffering a huge invasion of chinese small bikes from 125cc to 250cc and the marketplace is reponding to the demans, hence, the market forgot about the big bikes and their parts, and to top de cake, for some stupid reazon the goverment close the imports to a number of countries including USA, Japan and China...as you see is no easy...even spark plugs is difficult to get for this bike now...
Ok.. back to the problems, problem #1 has no solution until I get the boots, for problem #2 here is the question There is any way to set the float level properly without taking the carbs apart or off the bike?? Like many in this forum, the idea of start messing with this kind of carbs is rather terrifying needless to say I never was a carb smart guy...
Again thanks to all for the help.

 

I'd get the valves in spec before messing with the carbs, you will be just chasing your tail. Like Fitz said, do the valves first, then a compression check to assess the health of the motor. You need to start at the bottom and work your way up eliminating variables.

 

Re: Already run out of ideas and loosing confidence on the b

When I got my bike I was going to get someone to do the carbs, but figured I may as well learn, so I did it myself. There are some great step by step write ups on here, and they are nothing to be scared of. Just take your time, take pics for reference, and don't be afraid to ask questions on here. BigFitz, Rickomatic, and a few others here seem to never get tired of walking us through and answering the same questions over and over again. And if ya feel dumb asking, use the search function to find what ya need. It takes time but if ya don't do it right you're gonna do it 4 or 5 times and then do it right. (not that MY carbs have been off 4x :lol: )

 

Rod 1 - the first time I took my carbs apart I had no previous experience but follow the instructions from the forum and you can't go wrong besides it will be something you will have to do at regular intervals - so go for it, do it yourself and then you will be one step closer to understanding your bike.

 

Re: Already run out of ideas and loosing confidence on the b

Hi guys... I'll do it myself, behold for more questions!!!...
Answering a little to everybody, the valves were ok and the compression test was ok too. I had the luck to work with this guy at his shop while he was working on my bike so I was checking what was going on. I've been riding for 18 years now, I cannot call myself a mechanic guy but i'm not an ignorat either I do all the small work that don't demand big and expensive tools. Like I said I'll give it a try and I let you know.
Thank you

 

as long as you did check the valve clearances and made sure that they are in spec, then we can successfully rule that out.

I'm glad to see that you are going to dive in and do the carbs again....yourself. READ through the "Church of Clean" procedure and then take your time. When done, bench sync, and then bench set the floats. NOW you're at the starting point. Put the carbs back on, do a wet float test, again, info here on the site. NOW it's time to do the carb balancing and fine tuning. You'll get there! Hang in here, and DON'T get frustrated.

Dave Fox

 

Ok...I'll start to checking the valves. When comes to carbs, this are the facts because I saw the mechanic doing it.
-He cleans all the carbs
-resized the pilots, were out of sepc. (I bought the new ones)
-He checked the valves gap and were right
-replaced the air filter and the fuel filter.
-changed sparkplugs
After this the bike run very good for about 2 weeks, then the problems with the spark plugs start to show up, that's why I do not want to do a rebuilt in the carbs but like somebody said here maybe the float levels are out of spec.
I search the forum, so far I dind't find nothing specific about floats...Is there a way to set the floats back to spec without taking the carbs out of the bike or have them open??

 

In addition to "Church of Clean", please note that there is one and ONLY one article in the FAQ Final area. ... It is a "must read".

 

I ckecked and I don't know what you mean...

 

Quick question, if the floats levels are too high o not shutting off, Should be a leak from the carb. bowl? specially when the petcock is in "pri" position. Because i have no leak at all with the bike running or not, and the petcock in "pri" pos.

 

Article: Clean your own carbs - the Whole 9 yards by Rick Massey is the only item in the XJ FAQ Final:

http://www.xjbikes.com/Forums/viewtopic/t=2908.html

 

Not necessarily. It could just be dumping down the intake throat.

While you can CHECK the float levels with the carbs on the bike, it isn't very easy to do. You need to ensure the bike is level from side to side and prop up the front so the carbs are level front to back.

And since any ADJUSTMENT will require pulling them off, it's just easier to have them off to begin with.

 

Re: Already run out of ideas and loosing confidence on the b

schmuckaholic has a write up on doing the float level adjustment at XJ4Ever.com

If he changed the pilot jets then your pilot mixture screws will also need to be adjusted.

 

Hi Tskaz, I don't know if he changed the pilot mixture screws what I know is he change the pilot jets back to spec. Before there were 120 and 50, so I found the closest ones... 107 and 40 (instead of 36.5).
He also did the test with a vacuumeter(I'm not sure that's the word!)

 

Manometer ...

 

Wow sounds like your mechanic has got you all turned around...
40s instead of 36.5?? Thats a big jump.... Now you gotta shim the needles, bigger main jet to accommodate. Fun
Try listening to these guys. Theyve been doing it forever.
Clean your own carbs. Talk to chacal. Get the right jets and double check diaphram needles. Set your float heights. Get new Mixture jets and set them to 2 1/2 turns out.
Bench sync
Colortune
Sync
Ride
-Chris

 

Sounds easy... #40's is the only ones I can get in this part of the globe. Thing is that is not that easy for me send a pm to chacal and get me the parts I need since I'm not living in the US no more! Anyway I'm pretty sure this guy made the adjustment needed since the bike run pretty darn good for about 3 weeks. That's why I'll focus in the valve gap first, then the floats levels, besides I don't know what a "colortune" is, and of course I don't know what you mean by 2 1/2 turns out (I didn't have the time to check on the manual about the mixture jets) but like I said I don't think that should be the problem because when those things are off they are off from the begining and not 3 weeks later (I guess!!) I let you know how I'm doing, since tonight I'm gonna download all the information collected, tomorrow I'll start working... thanks

 

Are new mixture jets available and is 2.5 turns out the best place to begin when tuning them?

 

Indeed. That puts you at an excellent "starting point"

Rob, you might want to consider an In line Fuel filter as well.
What could have happened after the 3 weeks of excellent running, something from the tank slipped past the float needle and into the carbs. Or B: your mechanic missed something. Look it up. Do it yourself. Save yourself money and learn a thing or two. You have all your resources right here at your fingertips on this site
-Chris

 

Thank you Chris... Sure he missed something...and sure I'll learn more than a thing or two a lot more. Let me ask you, What is that you call a In line fuel filter? I mean It has some special shape?. I had the original one, wich I replaced by a small car model because I wasn't sure about the flow, plus this one I got now is all clear so I can see the gas inside and also replaced the black fuel hoses as well for clear ones, so again I can see if there were any gas flowing to the carbs, but I never here a In line fuel filter.

 

You've completely ignored what more than one of us have told you more than once:

CHECK YOUR VALVE CLEARANCES.

If you ever get this bike running you'll need to do it again in 5000 miles anyway. Might as well learn how. http://xjbikes.com/Forums/viewtopic/t=14827.html As long as you didn't leave an "X" off your bike's model (assuming yours is aircooled) then this will apply to yours too.

You won't be able to adjust the carbs if they're out of spec anyway.

 

Indeed
+1 thanks fitz

 

Not that i didn't read you guys about the valves, I'll check them again before dive in the carbs, What I said is he checked on the valves, I was there when he did it...make no mistake I will do and check anything to avoid to put my hands in those four in-line aliens I mean carbs..
thanks

 

Ok.... checked the valves and were ok, pulled the carbs out, and I blow them with compressed air trough the top hole and I noticed than one of the pinton valves open but doen't close back, I'll dig deeper, I'm taking my time, but I'll keep you up to date...

 

You cant be serious

 

Hey is my first time with carbs ever...I'm serious, "the courtains" is what we call them here, 3 close and 1 remains open every time you blow them.

 

Update...jets size were wrong and since here is hard to find them I had to make new ones out of the big ones, so out of the 50's I got the new ones 37, can't make them 36.5 as per manual...yes, float levels were off too, I thing that's all tomorrow morning I'll put them in and see what happens...

 

Tell you what.....why don't you go back down to the shop (oops, I said the word "s%#$p" again) and tell them that we said they have no clue what they are doing . When they tell you that WE have no idea what we're doing, tell them that there several THOUSAND of us here that DO know what we're doing, and the thousand here are saying that the 'shop' doesn't know what they're doing. Numbers.........we win--we outnumber them, and we have a WHOLE lot more bikes that are running the RIGHT way. Primarily because we PAID ATTENTION to those on the list that KNOW how things should be done.

ENough of the rant:

Now, here's a serious question for you, and please answer it specifically.

"When you (or they) checked the valves.....
HOW and WHAT did you check? Be incredibly specific.
WHAT were your clearance measurements?
WHAT were the sizes of the shims that were in the buckets?
WHAT size shims did you replace them with?
WHERE did you get the shims from?

I find it hard to believe that after all the people that have said to check the valves, and all the times you said you checked the valves, that you did it the correct way. Somethings not right. We haven't seen any specific information on your valves. I hope you're valve check does not consist of "oh, look.....yup, they open and they close, so they must be good'.

I'm not trying to be a jerk (I don't even have to try--I'm quite good at that), I just want to make sure that you're doing it the right way.

Carbs--be careful with that compressed air in the front of the carbs.....you could rupture a diaphragm.

Jets:

Here are the sizes you should have:

Model: XJ700
Fuel main: 107
Fuel Pilot: 36.5
Air Main: 70
Air Pilot: 210

Boots:

Make sure that the airbox-to-carb boots are not leaking air and are tightly sealed to the carbs, and correctly seated in the airbox.

Make sure that the Carb-to-intake boots are not leaking at all, and have no cracks. Make sure they are correctly sealed to the intake, and snug to the carbs with no leaks.

Compression:

What, spedifically, were the compression numbers?

Dave Fox

 

In many cases just start with the valve clearance and super clean and adjust the carbs on the bench. Put them on the bike and sync. It's not that hard just burns up an afternoon.

MN

 

An afternoon of EXCITEMENT and ADVENTURE!
Seriously.
Learn it. Then you'll know it. A sense of satisfaction in knowing that YOU did the job right and YOU made it run and YOU get to reap the benefits is worth its mental weight in gold
Eff your shop. You dont learn anything that way. If YOU do it then YOU will know it was done right cause you have every SHRED of information on this website at your fingertips.
Otherwise. Quit wasting your time. And ours. And most importantly. Your money
-ChrisMFAllen

 

Exactly. However, here we SEEM to have an additional issue with incorrect jets. BUT you're right... The valve clearances should be checked the RIGHT WAY and the carbs cleaned the RIGHT WAY, and then be synced.........the RIGHT WAY. Thanks for the succinct way of putting it, MN!

 

Dave and the resto of you guys, thanks a lot... Like I said before, not that I didn't check the valves gap, I DID and were the correct gap, problems was in the fuel pilot size they were replace in this form: the one in 36.5 (very old and for some reazon off-size) were replaced for a 50.0, the probably excuse is that we don't get the 36.5 here anymore wich is correct.
The fuel main were 107 (the right ones) were replaced for 102 and the floats levels were off too.
So I get some help to re-do the fuel pilot to the correct size, kept the fuel mains in 102, correct the floats, clean, sync, install and fire it up and works... first trip to give them a good try was sunday 200 miles at 70 m/h with no problems at all. Fuel consumption is around 4.5 liters/100 km, depending on speed and weather conditions, or 1.5 gallons every 65 miles roughly...I think is pretty good.
Going back to that shop only land me on jail this time, last time I wreck the place!!
Again thanks to everyone who helped me to understand the magic of the carbs, I still don't fully understant it, but I least can take them off the bike, check the jets, clean them, same with the floats and install them back. There will be more questions about the bike, I just hope they will not be about carbs for a long time now.

 

Huh. I guess WE forgot elevation differences

 

Congrats! I'm standing up and applauding! BTW, the fuel mileage comes out to just about 43.5 mpg. .

God job

Dave Fox

 

Thanks Dave. Talking about mileage... mine is about right ? or need to be like 50 mpg...

 

I consistently stay between 43 and 45 mpg on my 700airhead.

dave

 

Ok I feel good now...