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This Bike hates me - a tale of hateful carburetors.

Discussion in 'XJ Technical Chat' started by Trenchcoat, May 31, 2016.

  1. Trenchcoat

    Trenchcoat Member

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    Battery is tired again. Battery is likely going to get itself replaced very soon if it keeps this up. Bloody thing was fine a week and a half ago.
    I was able to get it to catch finally, was not easy at all, catches when I let go of the starter button instead of while I'm depressing it. Runs pretty terribly, I'm assuming due to the bench sync. I was trying to work with the idle speed and the choke, a bit less choke, listen, adjust idle, a bit less choke, listen, adjust, etc but even following that method once the choke was gone, the bike kept on poorly for a bit and then died on me. I'm going to have to give it a dynamic sync with partial choke or a high idle because it won't run without one or both yet.
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Once it's running wait for it to warm up before adjusting anything. The idle speed will come up as it warms. When it idels around 2,000 RPM, then you can ease off the choke and set the idle speed. You can then do a running synch, but you will have to keep adjusting the idle speed as you go, and will need to do a final idle speed adjustment during your first ride when the engine is at normal operating tempaerature.

    Not starrting until letting off the starter button is a clue to something, but I can't remember exactly what it is. @Polock? @hogfiddles?
     
  3. Trenchcoat

    Trenchcoat Member

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    When I have full choke the bike idles around 3-4k depending on the idle setting. Once I get get access to the neighbors electrical rig so I don't have to worry about killing the battery I'll get it running with as reasonable an idle as I can manage and I'll give it a running tune. Hopefully that will give it what it needs.
     
  4. Polock

    Polock Well-Known Member

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    low battery, starter stops drawing current and the TCI gets enough to fire the plugs.
    your mixture screws are 2.5 turns out?
    you can start a running sync at 3k, it's going to change as you get it dialed in but you have to start somewhere
    is your charger on the battery now? put it on and leave it there while you tune it
     
  5. cgutz

    cgutz Well-Known Member

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    One other thing I have noticed in starting - if you get a "pop" but not a start, your headlight will come on. Then it will still crank, but may not have enough voltage for TCI to fire.

    I find turning key off and on again, to shut off headlight, often helps it to start on the next attempt.
     
  6. Trenchcoat

    Trenchcoat Member

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    Alright, so with the neighbors machine to assist my aged battery, I was able to do running sync. Kind of Sort of. Turns out the single line of clear vinyl tubing doesn't exactly work very well, it's very (far too) sensitive and the fuel was getting sucked into one of the manifolds pretty much immediately so my friend and I had to experiment with kinking the line here there and everywhere to slow the transfer of fluid ((we used old gas) which I got a good mouth full of) to the point where we could actually follow the fluid with the screw, but with not being sure if everything was kinked evenly and other stuff I now know why the baby bottle device is better.
    In the end, the bike now runs. To me, it sounds a little funny, but for everyone else it seems fine. For now, I'm just very relieved because I can actually ride it, I was able to get a decent idle over 1k. The rolling, chugging hesitation on idle doesn't seem to be there anymore at all, I suppose it was those blasted throttle shaft seals. You have my thanks for recommending that.
    I think that all that the bike needs now is a better sync, and eventually I'll play with the air mixture screws, but naturally, ebay and amazon and I think everyone else seem to not have colortunes in stock, it's sounding a bit like they aren't being made anymore, so I'll have to wait til I can get my hands on the tool to do it justice. For the engine sync, I might break down and buy carbsticks, or see about a pair or two pair of vacuum gauges, or I might even make the baby bottle device if I can get parts for it.
    For now it runs, I'm no longer stuck walking across town for everything, so I'm pretty happy about things.
     
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  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The Gunson Colortune is still being made. Sometimes it's out of stock at several places due to demand. I'm pretty sure Chacal has some on hand. Start a converasation with him.

    I'd like to caution future readers (not you; what's done is done) against using gasoline to do a carb synch. The results of a backfire will not be pleasant. Automatic transmission fluid is much preferable, and not at all expensive.
     
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  8. Trenchcoat

    Trenchcoat Member

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    In hindsight, using fuel wasn't the best idea, I'll definitely agree to that. Stuff's far too thin anyway, I'd rather something that flowed slower, at least for the bare-bones line only approach I used. The potential for the line to go up in flames or worse doesn't sound too fun, though I'll admit it has that sense of danger I've missed since I've been unable to ride the last few weeks, heh.
    I'll see about finding the tools for the job of getting the bike tuned, the right way. We'll make a smooth runner of this bike.
     
  9. Polock

    Polock Well-Known Member

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    here ya go' save your money. read this thread. pay attention to the guy called "takingabreak".
    http://xlforum.net/vbportal/forums/showthread.php?t=31262
    when you get it to stumble going in and you start back out, go s l o w. three alligators between tweaks back out and a tweak is 1/8 of a revolution
     
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  10. Polock

    Polock Well-Known Member

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    two snapple bottles and some water work for me
     
  11. Trenchcoat

    Trenchcoat Member

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    What's being said in that thread definitely makes sense, sounds like it could very well work for me as long as I can correctly document exactly where my bike is set right now. I'd rather have those numbers just in case, since it's seemingly run pretty well, though a little lean and hot unsurprisingly. Sounds like getting the cylinders as close to perfectly synced as possible has to be the first step though if I'm going to use that method, since it relies on a slow, consistent, sure idle.
    Snapple bottles sound doable. More available to me than glass baby bottles seem to be. I imagine there's a range of vessel diameters where a good working tool can be made, larger diameters resulting in a slower moving fluid. I want it to be reactive, just not so much so that the tubes empty by the time I let go of the starter button to glance down at it as was the case with 3/16 ID clear line. There's also the matter of having to seal all of this up in a functional way, but I'm sure I'll get creative with it.
     
  12. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The key is restrictors in the line between the vacuum port and the bottle.
     
  13. Polock

    Polock Well-Known Member

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    only fill one bottle up half way, that way no water can get sucked up the line, then you can take your time and watch the bubbles :)
    to seal them just drill the hole a little small and force the hose through.
    plastic bottles can work but they may collapse, ignore that just keep working
     
  14. Trenchcoat

    Trenchcoat Member

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    Alright, So, a better manometer was built with a brace of mason jars and the same tubing I used for the rough tune. I was able to get it close, about as close as I think it was before all of this happened. I just took a quick 20 mile jaunt to feel how it's running, it's pretty much exactly as it was before, smooth idle, no real hesitation off of idle, smooth until around 4k, small vibration til 5k, by 6k it's smooth and continues that way until redline. I don't feel any real hangups at any point in the RPM range, needle tracked across the gauge without slowing down at any point in an idle to redline pull. It sounds as it always has.
    I'm thinking it's running a little hot, I'm still dealing with the situation where after a nice ride at full speed, the idle will hang at around 2k for a while before finally descending to 1.5 or somewhere in that area. I'm thinking the balance is good enough for a little bit of air mixture tuning, but I've had my fill of wrenching this month. That's a project for another day, and another thread. For now, I can get to work, I can ride out to Fitchburg with the friend with the now repaired Subaru, can cruise about with the neighbor on the 84 ironhead I've been helping him work on.
    Life can be good sometimes.
    Thank you all for your advice, your suggestions, your help. I'd be lost in the pits of despair without it.

    Good riding.
     
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  15. Jetfixer

    Jetfixer Well-Known Member

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    Sounds like synch still a little off...but at least it runs now....
     
  16. Polock

    Polock Well-Known Member

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    if it works for you, it's ok with me. remember, Aim small, Miss small
     
  17. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    ^ This is truly the voice of genius.
     
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  18. Trenchcoat

    Trenchcoat Member

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    I agree. I used the bottles, 1-2, 3-4, 2-3, and then I tweaked 1-2 and only had to check 2-3.
    I got it to the point for each pair where the levels will even out, the force of gravity balancing the water levels was greater than the force of unequal vacuum, so the fluid would flatten out and stay there. My only issue was that after so much time running, the sound would change a bit and then one of the cylinders would end up pulling just a little harder than the other, after 10 to 30 seconds of evenness, even with a couple of blips of throttle. I had a fan running to cool the bike, but that only does so much, so it's not like I could have the entire synchronisation done in one go while it was at perfect running temperature and no more, I would have to turn the bike off after so long, then start it up again and start making adjustments when I felt the bike was where it should be. I could see a better sync job being done, but I'd want an actual four carburetor tool of one type or another, enough fans to keep the bike running at perfect temperature more or less indefinitely, and most likely something to disable YICS with.
    I shouldn't have any air leaks at this point, I replaced all of the throttle shaft seals and I couldn't get any change in anything spraying the boots with WD40 or carburetor cleaner. I'll be tackling the air mixture as my next project, which will be after I've had some fun actually riding the bike for a few weeks.
     
  19. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Is your throttle tube clean and lubricated with graphite, or other dry-film lubricant?

    Why you wanna disable the YICS? It provides a fuel economy and power gain over the non-YICS engine ( a small one, but a free gain is a free gain).
     
  20. waldreps

    waldreps Active Member

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    I think he meant for when he does a better running synch. At least that's how I read it.
     

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