1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Need help fast valve shim

Discussion in 'XJ Technical Chat' started by Andrew.115, Mar 24, 2020.

  1. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    My 82 xj650 was running rather poor so I decided to check the valve clearance after I did I found out that cylinder 3 if you start from the left is measuring at (0.50mm) for the exhaust and (0.25mm) for the intake can they be that far off with out somthing breaking the reason I ask is because all the other valves are off but only by a little
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    11,156
    Likes Received:
    3,047
    Trophy Points:
    113
    Location:
    Great North Woods
    Valves having too much gap on them it's not as big of an issue as valves being too tight.
    Exhaust which is the front of the motor should be .16 to.2 mm
    Intake back of the motor should be . 11 to . 1 5 mm.
    So your valves are not opening as far as they should be which would have kept the valves from being pushed into the top of the piston and bending.
    It sounds like whoever adjusted them last mixed up the shims.
     
    Last edited: Mar 25, 2020
  3. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    11,156
    Likes Received:
    3,047
    Trophy Points:
    113
    Location:
    Great North Woods
    See the post in the do-it-yourself forms by big fitc 52 or the remake of that post by hog fiddles it explains how to do valve adjustments
     
  4. hogfiddles

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

    Messages:
    12,499
    Likes Received:
    3,791
    Trophy Points:
    113
    Location:
    near utica, new york
    If you wish, post all numbers here, and we’ll verify figures for you.

    also, I run a shim pool too—

    dfox
     
    Franz and XJ550H like this.
  5. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga

    Thank you so much I was just wanting to make sure nothing broke I've adjusted valves before but never on a motorcycle and never with shims
     
  6. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    I appreciate that I believe all the other cylinders are pretty much right but it goes as follows cylinder number 1 exhaust 0.18 mm intake 0.13 mm cylinder number 2 exhaust 0.18 mm intake 0.13 mm cylinder 3 exhaust 0.25 mm intake 0.50 mm cylinder 4 exhaust 0.18 mm intake 0.15 mm
     
  7. hogfiddles

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

    Messages:
    12,499
    Likes Received:
    3,791
    Trophy Points:
    113
    Location:
    near utica, new york
    So cyl3 is a mess. Pull those two shins out so we can find out what sizes they are. The size is stamped on the bottom side of the shim
     
  8. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    I also have another problem in cylinder 3 the Piston hit the spark plug and it's making a tapping noise now don't know if it's related to the valves or not could the valves being that far off be making a noise
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    11,156
    Likes Received:
    3,047
    Trophy Points:
    113
    Location:
    Great North Woods
    What spark plugs are you using that it would have hit the top of the piston? An XJ with correctly adjusted valves sounds like an old sewing machine. It should be tapping hi
     
  10. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    to answer a previous question cylinder 3 intake shim is 280 cylinder 3 exhaust shim is 270 and they were the correct spark plugs my throttle got stuck at 10000 RPMs and I had piston slap just not sure if the noise is the valves all because of the Pistons now
     
  11. SQLGuy

    SQLGuy Well-Known Member

    Messages:
    1,772
    Likes Received:
    90
    Trophy Points:
    48
    Location:
    Colorado Springs, Colorado USA
    10K isn't much over red line. I wouldn't expect valve contact at 10K. But at, say, 12K... Bent valves won't close correctly, and will have a lot of lash.

    I'd bet you get low compression on #3 as well.

    If you have a compressor, you can try setting the engine to #3 near TDC on compression and stick the air gun nozzle in the spark plug hole. If you hear a bunch of air blowing out the exhaust and/or out the carburetor, instead of pushing the piston down, then you can be sure you've got some bent valves.
     
  12. hogfiddles

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

    Messages:
    12,499
    Likes Received:
    3,791
    Trophy Points:
    113
    Location:
    near utica, new york
    I’d look close at a couple bent or stuck valves......there’s almost no way that a 270 and a 280 could have you THAT side open on clearances. If ANYTHING, you should be too narrow, and needing smaller ones.
     
  13. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    Well I appreciate it I was hoping it wouldn't be that but it was stuck in the back of my head
     
  14. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    yes it has zero pounds of compression on that cylinder do you know how the cam on those Motors time up or where the timing marks are I'm planning on taking the motor apart but wanted time before I do so
     
  15. hogfiddles

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

    Messages:
    12,499
    Likes Received:
    3,791
    Trophy Points:
    113
    Location:
    near utica, new york
    Setting the timing is with marks on the cams, and that’s all detailed in the factory manuals.
     
  16. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    Do you know of a place where I can view the factory manual
     
  17. hogfiddles

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

    Messages:
    12,499
    Likes Received:
    3,791
    Trophy Points:
    113
    Location:
    near utica, new york
    You should buy one for yourself on eBay—-

    otherwise, when you are ready to reassemble, we can show you the correct sections
     
  18. SQLGuy

    SQLGuy Well-Known Member

    Messages:
    1,772
    Likes Received:
    90
    Trophy Points:
    48
    Location:
    Colorado Springs, Colorado USA
    On the timing rotor, under the left side end cover, there's a T mark to line up with the pointer for 1/4 TDC. Turn the crank CCW to align this. #1 cam lobes should be pointing out, IIRC, at #1 TDC for compression. I think there are some markers on the cam sprockets that you can check for alignment, too. You'll need to remove the cam chain tensioner at the back of the block before loosening the cam cap bolts.
     
  19. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    11,156
    Likes Received:
    3,047
    Trophy Points:
    113
    Location:
    Great North Woods
  20. Andrew.115

    Andrew.115 New Member

    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Elberton ga
    Well thank you all so much for the help I really appreciated it I pulled the head of the motor off and found the problem that made me want to cry what's the best place to buy a motor seeing this world I don't want to pull the Pistons 20200328_160138.jpg
     

Share This Page