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valve clearance increasing??

Discussion in 'XJ Technical Chat' started by cg82, Oct 23, 2018.

  1. cg82

    cg82 Member

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    Hey Guys,

    So i've been working to get my valve clearances good. on the #1 exhaust clearance, It started tight at a .007 i believe (Don't have the exact numbers in front me me) after i changed shim to a 260, i measured the gap and it was .011 and I thought, this is wierd. Ok so i was going to change it again. it took me about 45min to get that little ring in the right orientation in order to be able to position the notice in the ideal spot. I had to tap and pry it around. Finally got it, figured I would throw a 270 in there and just check the gap, so I did. the clearance was now huge and I thought wtf is going on. I measured and it was .3! as large as my gauges go. What is going on?? I did notice that I must have scraped the side wall or something through the tapping and it looks like there is now some marking/gouging on the side wall of the hole, i'm wondering if i buggered something up and that is preventing the valve from not returning it its absolute top position which is causing the gap? help!
     
  2. Toomanybikes

    Toomanybikes Well-Known Member

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    After you swap a shim turn the engine a few turns to seat everything before you recheck clearance. And double check cam is pointing directly away from shim when doing so. And always that cylinder is at compression not valve overlap.
     
  3. cg82

    cg82 Member

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    done and done. still had the issue
     
  4. Toomanybikes

    Toomanybikes Well-Known Member

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    Don’t force the bucket. I just spin it when there is clearance and hold with chop stick until I rotate cam so it stays put
     
  5. Polock

    Polock Well-Known Member

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    the bucket should never need to be forced to spin
    if there were a nick in the bucket holding the shim up, the clearance will get smaller
    with the cam lobe up, try to tap the bucket down and see if it snaps up any farther, maybe the handle of a screwdriver on the bucket and tap the point
     
  6. mlew

    mlew Well-Known Member

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    I am curious on what method you used to hold the valve open to get the shim out. Zip tie or hold commercial hold down tool. Be aware if using zip ties under the valve that they can dislodge carbon and get on the valve seat keeping the valve from fully closing. When this happens to me I will spin the motor with the starter for up to 30 seconds and recheck.
     
  7. cg82

    cg82 Member

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    ok, let me clarify what ive done haha. i have the shim tool. I have changed all of the shims so am aware of the procedure. it works best when the little notch in the bucket is facing inwards so you can slip something under the shim to pop it out so while the cam is point away you spin the bucket, rotate the engine so the valve is depressed, instal the tool, rotate the lobe away from the tool, pry shim up, change shim and reverse. On the #1 exhaust, the bucket wasn't spinning so thats why i was tapping/prying to spin it. i have since spun the motor and the large gap is still there.
     
  8. jayrodoh

    jayrodoh YimYam Premium Member

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    I wonder if you bent the valve. These are interference motors meaning if the cable is open when the piston comes up to top it will hit the valve. If you had the tool holding the valve open and spun he motor around it may have hit. With the valve not closing now, that would explain the larger gap.

    I have no actual experience bending a valve on this motor but I have read from others on here that have reported this.
     
  9. cg82

    cg82 Member

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    i am not spinning the motor around, i am just rotating the cams back a bit as per standard procedure when changing shims. i looked at it more last night and i think that the bucket is binding up somehow. i'm wondering if the scarring in that, lets call it a bore, is preventing the bucket from moving up and down smoothly.
     
  10. jayrodoh

    jayrodoh YimYam Premium Member

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    Okay, you did say "rotate the engine" earlier which is why I mentioned it. I suppose it's possible that the bucket would be hung up on something but it would have to be a pretty good score in there to have the bucket hang up against the valve springs.
     
  11. cg82

    cg82 Member

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    Last night I was working on it more and what was happening is I would change the shim and then i would rotate the cams a fair amount of times using the starter and then i would get an accurate-ish measurement however I found that it would change. sometimes it would be tight, sometimes it would be in spec and others it would be a large gap. this bike has quite the gremlins!
     
  12. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    That sounds like a bent valve. Can you do either a compression test or a leakdown test on that cyl?
     
  13. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    If the tool is being used to hold the bucket down you can't turn the bucket at the time. That is exactly why I started using the zip tie method... you can rotate the bucket anytime since the valve is now held open from underneath
     
  14. Polock

    Polock Well-Known Member

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    is this how it's done? i'm not a tool kind of guy
     
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  15. a100man

    a100man Well-Known Member

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    Are the cam caps snugged down nicely?
     
  16. cg82

    cg82 Member

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    yup.
     
  17. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    If the bucket will not freely spin when it is NOT pressed down, something is jamming the bucket. If you use the zipties to hold the valve open, then y0u don't need the tool to hold the bucket down. It sh0uld freely slide down into the bore. If it does not, there's a problem. If it won't freely spin, there is a problem. If it moves up and down freely, and spins freely, there is no problem with the bucket. If the bucket does not come up far en0ugh, there is a problem with a valve sticking open, or a broken valve stem. If the bucket comes up to various heights, there is a valve that is bent and is hanging open depending on its orientation.

    A pressure test will confirm
     
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  18. cg82

    cg82 Member

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    i can't remember, is there somebody on this site that rebuilds heads or am i getting mixed up with the XS site?
     
  19. Toomanybikes

    Toomanybikes Well-Known Member

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    Have a head I stripped for parts due to piston Boom. Intake or exhaust valve?
    If you don’t have the tools you can send it down to me on the coast. And I can adjust shims off the bike.
     
  20. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Have you done any compression tests yet/
     

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