KLR Manual Valve Shim Calculation

The Jamie method.

Tool you'll need:
Pen / pencil

Clarification: I only did the left because both exhausts have the same spec and both the intakes have the same spec.
"Aren't ideal": they don't make them in as 251, 252, 253, 254. It's either 250 or 255.

The two boxes represent the clearance and the shim. The two added together is the total area you have to work with. Subtract the desired clearance, this is the space left to be taken up by the shim.

Exhasut Clearance Spec: .15 mm - .25 mm
Intake Clearance Spec: .1 mm - .2 mm
Also note that the shims are 29 mm in diameter. 29.5 mm shims are made for other bike. These will not fit, and you probably won't be able to tell the difference just by looking at them.

Because valves generally get tighter (clearance goes down) as they wear (not exactly sure why, but I do have a pretty good guess), it is recommened that they be set Price is Right style to the loose end of the spec, ie: as close as you can without going over.


Because I'm a reaaaallly nice guy, I even fashioned a spreadsheet for you. That will be available soon.



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Category:

Education

Tags:

• Valve
• Shim
• Clearance
• Computation
• Math

[hedlundk]

I wonder if it's possible to sand the shims using some very fine sand paper to bring it to the hundredths of a millimeter you would need? That's how you do Ducati valve adjustments. Sanding the existing shim to open it up a little is easier than buying a new one.

[ghotioutofh2o]

@hedlundk I don't see why you couldn't, except that you'd have to keep the surface flat and squared with the sides. i think it's easier to just get new shims.

[trav15106]

hey bro it would be nice t have sound on the vid.

[ghotioutofh2o]

@trav15106 There's sound. Turn your speakers on.... :-)

[guyNbluejeans]

Question: I'm due for my 12,000 mile valve check. However, my bike starts easily and seems to be running well. Sooooo do you think I'd be a fool to hold off on the valve check since money's a little tight?

Also, I was planning to do it myself ... but since via this video you've informed me that one needs to be a mathematician I suppose I'll save up the $400 smackers and let the experts go over the whole thing with a full service job.

Btw, thanks for being a sport and posting this vid!

[ghotioutofh2o]

Haha, funny you bring that up. I just perused one of my old computers and found an excel sheet I made that does the calculations for you and tells you what shims you need where. Give me your email address and I'll email it to you. Don't waste $400 on it. Go buy some feeler gauges for maybe $20 and do it yourself. :-)

To answer your original question: it doesn't hurt to check the clearances. My bike was running fine but were out of spec on the tight side.

[SnoozeXXX]

Thank you for posting this. Nice Work!

[britfin007]

I am sure this is a very informative video but for me personally I gave up the will to live at about 1.26 ;P

[Hot80s]

Thanks. now i have to do it to a 5-valve genesis block, uuggghh.