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Valve shim question - first post

Discussion in 'XJ Technical Chat' started by PaulCampbell, Feb 16, 2017.

  1. PaulCampbell

    PaulCampbell New Member

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    Good morning one and all

    I recently purchased a 1980 XJ650 4K1 here in Australia and I have been reading reading reading this forum. There is such a vast ammount of knowledge here and a very helpful crowd.

    I am new to road bikes and I am in the process of checking valve clearances and of course I have some questions.

    Here is what I have come up with so far with regards to the clearance and what shims I and what shims I may need.

    When I measured the Sims to check then I noticed that two of them were .01 millimetres shorter than they should be. Should I allow for this in the calculations that I make? As you can see on the chart it will mean either leaving the shim or replacing it.

    Any help would be greatly appreciated kind regards
    Paul

    BONUS pic of the valve shim tool I made
     

    Attached Files:

    Last edited: Feb 16, 2017
  2. hogfiddles

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

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    First-off... Either your measurements aren't right, or someone really screwed up.

    Exhaust 1 and exhaust 4 have shims that are too thin--your clearance is out of spec on the wide side.

    Your intake clearances are all took ode, except for #4 which is in spec

    Can you recheck?
     
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  3. Stumplifter

    Stumplifter Well-Known Member

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    Bob's your uncle! :D

    Thanks for the bonus pic!

    What Dave said, recheck the clearances and make sure your lobe is 180 degrees away from the shim when measuring. The 'oddball' shim thickness is what it is . . . bonus points to you for measuring the shims instead of relying on the stamped on size alone. Knowing exactly what is in there makes it easier when doing shim changes. Often times you can do the shim dosey-doh instead of acquiring a whole group of them.
     
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  4. k-moe

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

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    The following post contains irony. See if you can spot it.

    Here's the valve shim tool I made.

    [​IMG]

    As for the measured shim sizes, in-spec is in-spec. A 0.01 mm difference is not enough to put the valves out of adjustment.
    Quick Q. What did you measure the shims with? The 0.01 difference could be simply due to lack of resolution (going out two more decimal places may reveal that the shim is within manufacturing tolerance, and not actually worn).
     
    Last edited: Feb 17, 2017
  5. Polock

    Polock Well-Known Member

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    i mic all my shims and their never exact. just read the number and be happy
     
  6. PaulCampbell

    PaulCampbell New Member

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    You guys are great! I didnt expect such a quick reply.. and from the big guys on the forum too, so thank you :)

    hogfiddles - so that I understand better are you saying that the valve clearances should be reduced over time and usage, and the valve clearances at the moment are too large meaning a) either PO has used the wrong size shims b) my measurements were way out.
    If a) then 1 2 3 on the intake side are concerning too. Makes me think that the problem is with my measurements.

    Stumplifter - Welcome for the bonus pic ;) and thank you for the encouraging words, I was only measuring them to see if they actually wear down, and found that it was the circular strike area that was .01 less than the edge of the shim.

    k-moe - I can not see the picture that you posted for some reason but shall I assume that it is a pic of the shim removal tool you made? if it is I came across the pic of yours after I made mine.. you did a great job, made me want to tidy mine up a bit more ;) I checked the shims with Mitutoyo analogue micrometers. All measured up pretty well and was surprised to come across the short ones.. I was checking again with another mic then checking the mics against my feeler gauges to make sure it was actually the shims lol

    Polock - Im glad to hear this is not unusual but I will mic the new shims just so I know. Funny thing tho - the two shims that came up short did not have numbers zapped onto them.. not even a shadow where the number may have been. No evidence of grinding either so that leads me to believe someone has produced shims not incremented in .05 or the manufacturer of these ones had lousy quality control and poor stamping.

    I will recheck the clearances tonight and once I am finished swearing I'll post my findings
     
  7. hogfiddles

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

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    The reason for doing the regular shim clearance check---

    Over a period of time, the valves will slowly recede into the head through constant pounding. That makes the valve stem get closer to the cam, making the clearance gap get smaller. So, thinner shims get swapped in the create the correct clearance again. Til a some point it is adjusted again
     
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  8. PaulCampbell

    PaulCampbell New Member

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    20170218_000512.jpg 20170218_022900.jpg 20170218_022900.jpg 20170218_022900.jpg Most of this is new to me so thankyou hogfiddles for clarifying.

    I measured the valve clearance again with the help of my brother using a more gentle approach and this is the result.

    What I dont understand is why I am still seeing a larger than ideal reading on a few.. how does this happen?

    I have also attached the 'notes' that I found slipped into the haines book by the PO. This may help to understand what the po was up to..
     

    Attached Files:

    Last edited: Feb 17, 2017
  9. dkavanagh

    dkavanagh Well-Known Member Premium Member

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    It would be odd to go up in shim size. Only thing I can imagine is the PO messed up in a shim swap and went too small. That would lead to a valve not opening enough.
     
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  10. XJ550H

    XJ550H Well-Known Member Premium Member

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    in spec is in spec
    by your new numbers.
    ex 1 needs to be changed with 265 shim

    ex2 is in spec
    ex 3 in spec
    ex 4 inspec

    intake 1 ,2 ,3 need to be changed 240 235 260 respectivly
    intake 4 in spec
     
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  11. k-moe

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

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    Some people intentionally go a bit on the loose side, knowing that the clearances will tighten up. I am not one of those people, but I understand why it happens. Say that have shims on hand, and the valve cover is already off. The bike is new to you, and you find that the clearances are in spec, but nearing the tight side. May as well go haead and change the shims rather than guess at when they will need to be checked again.
     
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  12. PaulCampbell

    PaulCampbell New Member

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    Oops, sorry. I saw someone else here that made a tool similar to mine and just assumed it was you. Now I can see the picture lol.. totally different. I considered that method but wanted to have a crack at fabbing one ;)
     
  13. PaulCampbell

    PaulCampbell New Member

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    From reading through other stories I see one here previous owners have a lot to answer for. The bike was running, but they had messed up a few other things too.. float levels was one of them, they also had the mix screws backed out over 3 full turns. When I pulled the plugs there was enough soot build up to scare a chimney sweep. The carbs have the coarse threaded mix screw meaning 1.5 -1.45 turns out is a good starting point. Im waiting for a colortune plug to be delivered :) cant wait!
     
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  14. PaulCampbell

    PaulCampbell New Member

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    Thank you kindly for the information here, got the new shims in today and went back through with the feelers. Intake 2 ended up with 0.10 clearance so I stuck the other shim back in and its within tolerance now. Thanks again :)
     
  15. PaulCampbell

    PaulCampbell New Member

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    To me that is just lazy, not something you would catch me doing ;) I actually think the PO didnt really know what they were doing.
     
  16. PaulCampbell

    PaulCampbell New Member

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    Well with the valves all sorted I had a look at the cam chain..

    With a good tug I could lift it about 30mm off the guide between the two cam gears. Bloody hell I dont think it had been checked for ages as there were score marks inside the valve cover.

    I followed the instructions in the book and the ones listed here and got a nice positive click when I backed off the manual adjusment screw on the tensioner. Now there is about a 1/4" play when I lift the chain off the guide. Is this suitable ammount of play?

    The bike is not registered yet an I have only taken it up the street a couple of times to see how it runs. After I buttoned it up today I went for a quick couple of runs up and down the road. All I can say is WOW.. big difference. The bike pulls way harder than it did before and I pulled back into my driveway with a grin from ear to ear. I still have to set mixture screws once my colortune arrives and I have only bench balanced the carbs so far but Im excited to see how it goes once I get that sorted.

    20170129_010025.jpg 20170129_005406.jpg

    On a side note my cousin and a mate were using my garage today to rebuid some brake calipers. They watched me when I went for a ride and when I got back their exact comment was 'holy shit man, it sounds tough' and 'f*** it sounds like a sports bike'
     
    Last edited: Feb 18, 2017
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  17. Stumplifter

    Stumplifter Well-Known Member

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    Ahhh that XJ smile. :D

    Afore you go much further strongly recommend you go through the brakes (front and rear). Stainless steel lines up front, rebuild caliper, mastercylinder and replace the old shoes in back.

    Being able to stop when you need to is a lot more fun than the alternative . . . .
     
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  18. hogfiddles

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

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    Another possibility---the PO was using a manual with the wrong chart..... some manuals are printed wrong.

    Also---

    Possibility the PO was using the correct charts but got intake side and exhaust side mixed up when writing stuff down.... wouldnt be the first time I saw that---
     
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  19. PaulCampbell

    PaulCampbell New Member

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    Thank you for the heads up Stumplifter, I have a list of things to take care of before it gets registered and those things are on it :)
     
  20. k-moe

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

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    Not lazy, smart. If you don't know when the last valve clearance check was it makes sense to go a tad (and I do mean tad; as in one shim size) on the loose side so you can run to the next scheduled check (by mileage, with the current check being mile zero) without trouble. The valve clearances will tighten up. I don't do that myself, but I'm in a position where I can make free time to check things early if I need to.

    Having said that; assuming that the PO was ignorant is always the correct choice.
     
    Last edited: Feb 18, 2017
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