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Odd size shims

Discussion in 'XJ Technical Chat' started by KA1J, Jul 28, 2015.

  1. KA1J

    KA1J Member

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    Today I checked the shim sizes in the Maxim X and instead of getting values in multiples of five, I have seven shims with number 188 and I have one shim with 192.

    One exhaust measures .20mm and the shim is 188. The valve clearance adjustment tool doesn't account for that number and it looks like it would come out to 183 So I'm not sure if I should go for 180 or 185.

    One intake measures .12mm and the shim is 188. That's close to the tight end of tolerance (.11 ~ .20) so I'd like to get more gap, closer to .20 What shim would I need?

    Another example is the intake measures .6mm but the shim is 188 so would I be best with a 175 or 180?

    I'd really like to get the values to be closer to the wide end of the normal limits.

    First time I've seen odd size shims.
     
  2. hogfiddles

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

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    Those are normal numbers for the X shims
     
  3. KA1J

    KA1J Member

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    But the numbers don't show in the chart in the service manual..
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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  5. KA1J

    KA1J Member

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    With the assistance of a friend's Excel spreadsheet I was able to enter the measured gaps at TDC and the values of the shims at those locations and it gave me the minimum thickness of the needed shims to give the max allowable clearance. I contacted a local shop and they had the needed replacements so was able to get the cams re-installed today.

    Kind of a challenge at first, getting the cams in just right, but I found a neat trick that is obviously there for the purpose but I missed mention of it: There are holes in the cam that if you put a rod or Allen wrench the same size into, it fits into a notch in the cam cap of Cylinder 4 (both intake & exhaust sides have that hole and notch). It holds the cam in perfect alignment to match the pointers on the cams & Caps at cylinder 3. With the allen wrench in there held firm in that notch, I had no problem lining up both sprockets and with the engine at TDC, all went together fast and with no issues.

    Ran a leakdown test while the cams were out of the head and all cylinders were well into the green with minimal leakage.

    Now to read up on the best way to make the gasket for the cam tensioner ( the old one came off cleanly) and how to put the tensioner back together properly.

    Always something to read up on ;)
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    yup if we aint riding we reading :)
     
  7. iX.

    iX. Member

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    I had 188's and 182's in mine among the rest of the normal ones -- 190, 185, 180, etc.

    I ended up modifying the chart to show where the actual measurement would have been inside the tolerance zone. Then figuring out what a particular shim would exactly add or remove to my clearance, for example, if you had a 188 and you put in a 180 the difference would be .08mm. By doing the math on it you can see where difference sizes of shims (all of which would put you somewhere inside the spec) will actually land, and, you can deal with odd sizes like 188 that aren't on the chart. For most shims there are actually two that would land within the tolerance zone so this way you can pick where you want to be within this zone. This also gave me a clear answer as to what to do when my measured gap (with imperial feelers) actually landed between two metric measurements. Rather than doing a very course adjustment picking the next one up or the next one down, just apply the math and you pop out precisely with the projected final gap, no matter what gap you measured or what oddball shim you run into.

    All within specs now... spit out some 188's and actually re-used the 182 elsewhere as it turned out I shorted myself one 180 on the final tally --- still within spec by math and by observation after assembly on that one.

    Now if I only had a leakdown tester...
     
  8. KA1J

    KA1J Member

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    Well done.

    Not sure if you have a Harbor Freight around you but I paid $35 for the Chinese Junk leakdown tester but it seems to work well enough. Beware, the instructions are incomplete: You need to have your air supply hooked up, adjust the gauge to read 0 with the air you have (keep under 75 pounds pressure), max clockwise measurement to get to zero and then, connect to the extension in the cylinder to get your leakage values. I tried following the manual and it made no sense to me, they left out some steps. Once you know how to set it & read it, it's an OK tester.
     
  9. Toomanybikes

    Toomanybikes Well-Known Member

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    Those odd shims are factory original setup ones . Honda also had a few odd number shims and for some adjustments its great to have but don't plan on adjustments based on those odd shims. Once in a blue moon you can use one or two to get settings perfect, have one in my cb900 so all valves are in middle of range. Next service will be in 2020 by the time I put another 2500 Kms on the bike and that shim will end up in the kit for next bike
     
  10. iX.

    iX. Member

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    No Harbor Freight stores in Canada as far as I know -- anyone have any leads on inexpensive units from Canadian chains?

    I'm ok with Chinese Junk as long as it works... I can decode chinglish and won't use it more than a couple times a year so it doesn't need to be especially durable, just functional.

    We have a regulator on one of the compressor outlets where we can set any pressure we want so it shouldn't be too tough to accomplish if we have the right unit.
     
  11. iX.

    iX. Member

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    Actually I'm just booking a flight for a business trip right now to FL for the end of the month, I can pick one up while I'm down there. Would have been nice to have it right now while the motor is going back together but it will give me something to play with in the winter. :cool:
     
  12. KA1J

    KA1J Member

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    It's pretty basic but it does the job nicely. And it's cheap. If you look on their web page for coupons & sales, you might well find it on sale.
     
  13. iX.

    iX. Member

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    Will definitely drop in on one of the stores while I'm in Florida a couple weeks from now. Looks like there is a bunch of stuff I might want to get from there. My carryon bag may look a little odd though. :cool:
     
  14. KA1J

    KA1J Member

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    I just bought a 21 gal compressor from HF for $149 with a coupon. tough to get that on carry-on but it's worth a try! ;)
     
  15. XJ550H

    XJ550H Well-Known Member Premium Member

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    strip search for you on return:eek: :eek::eek:flight
     
  16. k-moe

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

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    Nothing to declare.
     
  17. MattiThundrrr

    MattiThundrrr Not a guru

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    When I flew back from florida, I left at 6am. Even though my bag was 30lbs overweight they didn't want to search it... customs agents were too sleepy!
     
  18. XJ550H

    XJ550H Well-Known Member Premium Member

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    when I drive into Canada (60 miles) I get to the crossing and a sign tells me to drive down a road to the boarder crossing building instead of just continuing down the road i'm on.
     
  19. MattiThundrrr

    MattiThundrrr Not a guru

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    Still some free spots left in N.America!
     
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