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1981 Yamaha XJ650 Maxim Valve clearance/ carb issues

Discussion in 'XJ Technical Chat' started by kcleft, Feb 11, 2014.

  1. kcleft

    kcleft Member

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    The description says it works with my bike so I might go that route! Is there any problem with his listings? If it's only going to cost 30-40 bucks then I'll just order them if you guys think that's a good idea :)
     
  2. FtUp

    FtUp Well-Known Member

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    I have ordered several from this guy, for both of our xj's the 29mm shims are a perfect fit.

    CN
     
  3. MiCarl

    MiCarl Active Member

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    There is nothing wrong with those shims. Price seems high though. Although free shipping is a big deal on a small order......

    What does Chacal get for shims?
     
  4. kcleft

    kcleft Member

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    Alright! I just ordered the new shims, so hopefully within a week I'll be able to start her up! :) thanks for all the help guys!!!
     
  5. Polock

    Polock Well-Known Member

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    your too quick on the trigger
    Z1
     
  6. kcleft

    kcleft Member

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    Ah, I see.. haha oh well. They're already being shipped and I just ordered them today. It probably wasn't worth an extra 10 bucks to skip a day or two of processing, but it doesn't matter at this point haha. Thanks for the website though! If I need new shims again I'll know where to look :)
     
  7. kcleft

    kcleft Member

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    Update!!! I got the shims Saturday, but I didn't have time or the light to replace them. Same for Sunday and Monday, but I finally had some time today and I managed to replace the shims and put everything back together!! The good new is that it runs. The better news is it sounds like it's running better than before! The bad news is it won't idle at all and it's developed a new symptom. You still have to use starter fluid to get it started and you have the hold the throttle open at least 1/5 of the way open (so around 4k. I didn't let it heat up long enough to see if the hanging idle was still there, but the throttle was very responsive when I revved it then backed off). However now if you let go of the throttle, or back it off too much, it will pretend to idle around 2k and even if you open the throttle all the way, it won't move from the 2k.. and in a matter of seconds it will die all together. I'm pretty sure It's just the carbs, but I don't know where to start. Also kind of on a side note, it's making an interesting sound, kind of like the sound when you pop bubble wrap only louder.. so.. hopefully someone on here knows what that is... haha. Thanks for all the input so far you guys. You've all been extremely helpful!!
     
  8. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Popping=lean.

    Quit running the poor thing. Yes, carb time.

    You've already achieved a milestone. Don't stop now. Good work (so far.) Don't get ahead of yourself. Proceed to Section 2 of the "Periodic Inspections and Adjustments" chapter in the manual.
     
  9. kcleft

    kcleft Member

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    Is that section in the haynes manual? I can't find it, all I could find on the carbs was how to synch non-yics carbs.
     
  10. kcleft

    kcleft Member

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    Also on one of my many XJbikes journeys I found this: http://xjbikes.com/Forums/viewtopic/p=215851.html would this be a good route to go to get my bike to idle? I know for the 'finer' tuning I'm going to need car sync gauges, as well as a colortune.
     
  11. MiCarl

    MiCarl Active Member

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    Did you ever re-do a compression test? If the numbers are really that low you've got more than carb problems.
     
  12. rmcrow

    rmcrow Member

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    Hi I am another new guy that just bought an xj and got it running right, it was ready to blow.
    You will not have to buy either a manometer nor a colortune if your willing to do a little extra work and save some money. With some 3\16 flexible tubing a couple of yard sticks 2 T joints and a board you can build a manometer. By doing plug chops you can set your mixture. And you won't have to mess with yics like most of us did either.

    The best advice I read on this site that I followed that let me avoid so much trouble was all the comments about cleaning the carbs. Really follow the whole nine yards and the church of clean. I spent about 45 minutes per carb and a full 12oz can of carb cleaner on each one. Following step by step TWICE before moving to the next one. Oh yeah and building a rack that held my carbs up at shoulder level out of PVC made the wet setting a real pita but probably saved me from having a 12 hour job setting them. It took me 4 working really slow and careful and just blowing on the float tangs and looking at them funny to bend them by super tiny increments. But they work and the first time and I haven't had to redo or adjust anything else on them.

    All my other problems after that have been electrical.

    Really really take your time.

    Since bigfitz is helping you look at how many posts he has had to make to people saying redo your carbs, you didn't do it right.

    There is also someone on here who made themselves some new intake boots out of flexible plumbing connectors. If you build a carb rack from PVC you will buy two anyway, why not buy five and make new boots. ( one to screw up)


    Good luck. These are sweet bikes and making them go braaammmm zoooomm really rocks.
     
  13. kcleft

    kcleft Member

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    MiCarl: no I haven't done another compression test yet. I don't actually have a tester, I used a friends. I'm probably going to try to go to autozone or somewhere like that tomorrow to rent one, so hopefully I should be able to give you guys some results!

    rmcrow: thanks for the advice! I ended up using 1 can on all the the carbs when I took them apart last time. The carbs were VERY clean though when I took them apart the first time. The previous owner had definitely taken them apart before. I did my best to completely disassemble each one, and ya I probably spent.... 20-30 minutes on each one. But I really cleaned the jets, bowls, and passageways as best as I could. I don't have access to compressed air unfortunately, but I still think they got pretty dang clean haha and I did add an inline fuel filter this time round so it should keep those jets clear :D
     
  14. rmcrow

    rmcrow Member

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    I don't have a tank compressor either so I bought some duster. Don't know as it actually did much good but I did use it to check everything was clear.

    Good luck on getting everything going.
     
  15. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Carb service is covered in the Haynes beginning on page 119. Be aware that pic 7.9b has the jets labeled incorrectly.

    Pay special attention to the emulsion tubes (pic 7.10a) they need to be clean inside and out and the tiny holes all clear.

    Make sure you pull the pilot screws, replace their tiny o-rings and be sure the washers are still there.

    Setting float levels is covered on pages 126 and 127, and explained even better here: http://www.xj4ever.com/setting%20fuel%20levels.pdf

    Be sure you do an uber-accurate bench sync, it will make the running vacuum sync much easier.
     
  16. kcleft

    kcleft Member

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    ok, so my question is how do I remove the emulsion tube? that is the only thing that I didn't manage to clean. The manual doesn't specifically tell me how to do that. can I use a small socket and kind of tap it out? And I did a bench sync last time using a cut up debit card and they are all pretty dang close. Also where can you get replacement O rings? the ones that were in there previously still look ok, but I guess replacing them couldn't hurt! And I still need to remove those seized screws in the bottom of the float bowls... I'll try an extractor, but last time I did, it just snapped on me...
     
  17. rmcrow

    rmcrow Member

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    Whenever you take off the jet right above it it should be free to slide out. If it doesn't just turn the carb upside down with your hand over it and knock it a few times with a screwdriver handle and it should fall into your hand.
     
  18. kcleft

    kcleft Member

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    Ok, it definitely doesn't slide out into my hand. I'll try using a screwdriver handle idea. thanks!!
     
  19. kcleft

    kcleft Member

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    that makes me think though, if it won't come free easily, then there is a good possibility it's never been removed. And it needs to be cleaned really bad haha
     
  20. quebecois59

    quebecois59 Well-Known Member

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    Remove the main fuel jet at the bottom end of the tube (the emusion tube is bolted to it), turn the carb upside down and use a wood dowell and a small mallet to tap the emulsion tube out. Don't try to turn it right or left, there's a tab that prevents any side movement.
     
  21. kcleft

    kcleft Member

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    ok, thanks for the tips! as soon as I get home, I'll take them apart again lol
     
  22. rmcrow

    rmcrow Member

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    It will come out through the top of the carb. Not the bottom where the jet is. Just to make sure you know.
     
  23. KrS14

    KrS14 Active Member

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    You can also partially screw the main jet back in (not all the way tight), and use a wood dowel on the main jet to knock it loose.
     
  24. kcleft

    kcleft Member

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    So I got them loose and everything looked extremely clean! I sprayed them with carb cleaner anyways. Now I'm getting things set up to run a compression test. Also when I removed one of my spark plugs I noticed the gap was EXTREMELY small... I though when I had them removed last time that they were close to the spec. could just be me of course, but is there anything that would cause the gap to close like that?
     
  25. kcleft

    kcleft Member

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    Nevermind, I just went outside to double check the gap and it's .025in, which I believe is in spec. It was just my eyes deceiving me haha
     
  26. kcleft

    kcleft Member

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    Had a chance to run a compression test (engine was cold) and they were all exactly 75psi! I know it should be more than that, but that's much better than 30-40psi I bet after it's warmed up it might be closer to 90 or so.
     
  27. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Try again with a different gauge. Make sure you use a fully charged battery, all plugs are out, and the throttles are blocked wide open.

    The fact that they all match tells us that the readings may be at fault; for all 4 to be equally horribly low it points to the gauge rather than the motor at this point.
     
  28. kcleft

    kcleft Member

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    ok, I'll see if I can find another gauge. I had all the spark plug removed and that battery I know is toast, so I did jump it to a running vehicle. And the throttle was wide open as well. Any idea what it could be if I get close to the same results with another tester?
     
  29. rmcrow

    rmcrow Member

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    With all four stopping right at 75 that's just a bad gauge, something was keeping it from registering at anything higher. And you should jump to a vehicle that is turned off even when you are just hot wiring directly to the starter to avoid damage. And don't get impatient or angry, you are making progress.
     
  30. kcleft

    kcleft Member

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    alright, So I'm still working on getting another compression test done. I just had a quick question. Where can I get replacement carb bowl level check screw?. If I'm lucky I'll be able to use an extractor to remove the plugs.. if not.. then I guess I'll have to drill them out :(
     
  31. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Dude. Parts: XJ4Ever. Anything you may ever need.

    Click the logo/link in the upper right of the site banner, PM member chacal, or send an email to "info AT XJ4Ever DOT com" and Len will hook you up.

    Virtually every one of us that rides our XJs with great regularity relies upon XJ4Ever to keep us on the road. If you need it, he's got it in stock and it will be correct, unlike a lot of eBay parts.
     
  32. kcleft

    kcleft Member

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    Hahaha you told me this before and I totally forgot. Thanks man, I'm definitly bookmaking XJ4ever. On a side note, do I actually need to remove the drain bowl screws to check the float hight? I noticed that in one of the pictures he shows in "checking float height" that the Hitatchi carbs have a drain nipple, and he shows a picture with a see though line attatched to the nipple measuring the float height. Can I just hook up a line to there, or is there something special I need to do?
     
  33. rmcrow

    rmcrow Member

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    You have to be able to open the drain screw to get gas to flow out of the drain nipple. If you have one that you can open you can swap it from carb too carb as you go.
     
  34. kcleft

    kcleft Member

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    Hahaha I didn't even think about that! I have two bowls that have a free moving drain screw and 2 that don't. So I don't remove the drain screw all the way right? just enough for the gas to drain out the nipple?
     
  35. quebecois59

    quebecois59 Well-Known Member

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    Yes, that's it. That's what the drain screw is made for.
     
  36. rocs82650

    rocs82650 Well-Known Member

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    kc,

    Quick question...Are you removing the air filter and dis-connecting the tci when you do the compression test? You will also need to be able to crack those bowl plugs after you set your fuel levels and re-attach the main line to the tank to bleed air out.

    Roc
     
  37. kcleft

    kcleft Member

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    I disabled the ignition (removed fuse), but I didn't remove the air filter, should I take it out?
     
  38. FtUp

    FtUp Well-Known Member

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    you don't have to remove the air filter for a compression test.

    CN
     
  39. rocs82650

    rocs82650 Well-Known Member

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    kc,

    Like cyclenoob said, you don't have to, but because you have such low numbers I am suggesting it. See Chacal's write-up on Compression Testing under the Information Overload Forum. (c) remove the air box lid and remove the air filter.

    Roc
     
  40. rmcrow

    rmcrow Member

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    Though if you are going to be working on your carbs removing them will free up the hand you are using to hold the throttle open.
     
  41. Polock

    Polock Well-Known Member

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    Has this engine run since the valves were done?
    Your sure the shims are seated right?
     
  42. Polock

    Polock Well-Known Member

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    Has this engine run since the valves were done?
    Your sure the shims are seated right?
     
  43. kcleft

    kcleft Member

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    Yes the engine does run, I'm pretty sure the shims are seated right. When I did kind of a final inspection after rotating the engine a few times with the valve cover off, I checked all the shims were seated right. It does sound quite a bit better! I know I've definitely got to get those carbs adjusted right. But first is the compression test. I've been working all day and haven't had the time nor the weather to run the test. I might remove the box and filter though if I'm still getting relatively low readings. Hopefully by Tuesday I'll have more for you guys! I'll post as I get more done. Also I was looking into ways of syncing the carbs, and I don't want to spend 50-100 bucks on a sync. So I was looking into building my own kind of manometer and I came across this: http://www.youtube.com/watch?v=GaTRyHxvneY what do you guys think?
     
  44. MiCarl

    MiCarl Active Member

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    That should work. By the time you chase up all the parts you'll have almost as much sunk into it as a gauge set. Plus any time you suck a bottle empty you'll have to refill/bleed/calibrate the thing.

    If you look on eBay you can find the 4 gauge set with the aux fuel bottle that you can have for under $90.

    But, I've pointed this out twice and won't again:

    You are wasting time and money until you find out if your compression is good. You can sync and tune until the cows come home and a 75PSI engine will NEVER run well.
     
  45. Polock

    Polock Well-Known Member

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    i did my valves and checked compression when i was done
    60 - 120 - 125 - 65
    started it and let it come off choke and checked again
    120 - 120 - 125 - 115...........? don't know why, really don't care.
    if you can adapt a compression tester hose to a compressor, you'll hear where your problem is.
    make a 2 bottle sync tool, they cost 1/2 as much and work better
     
  46. kcleft

    kcleft Member

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    Alright guys! I had just enough light to run a compression test! I removed all the spark plugs,hooked up the battery from my truck (engine was off) to the bike, removed the air filter and air filter cover, and opened the throttle wide open. here are my results:

    cylinder 1: 110psi
    cylinder 2: 105psi
    cylinder 3: 115psi
    cylinder 4: 120psi

    (give or take a psi or two ;) )

    Also I should note that the engine was completely cold, probably around 40 degrees and the bike hadn't been ran for about 2 or 3 days, so there probably wasn't a ton of oil on the rings either. These results are a TON better for sure!! Hopefully MiCarl you will approve of these results ;) Polock were you thinking of something like this? http://www.youtube.com/watch?v=GaTRyHxvneY
     
  47. rmcrow

    rmcrow Member

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    That's a good test then. Your valves are seating and you're rings are mating well with the cylinder walls. Now on to the dodgey electrical systems and the carbs.
     
  48. kcleft

    kcleft Member

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    I think for the most part all the electrical's work pretty well :) The only thing that bugs me is that starter button is intermittent haha and that's probably just cleaning up the contacts really good.
     
  49. MiCarl

    MiCarl Active Member

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    It's not a matter of me approving them, I just hate to see someone throw time and money at a shot engine.

    Now you know you have an engine that will run, and when it doesn't you'll know it's something external.
     
  50. Polock

    Polock Well-Known Member

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    KC, i'am thinking 1/2 of that, two bottles, one screw adjusts two bottles then move to the next set, then adjust the two sets with one screw.
    no deciding what screw which way.
    the weight of the screwdriver can change the readings and you should blip the throttle before you call each set done.
    four bottles makes me think too much, the more i think the more mistakes i make :)
     

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