quick valve shim question

hi all

im doing my first valve shim and need a little help

so the exhaust specs are 0.17 to 0.22

its either be 0.18 or 0.23 what do you reckon?

So what your saying is with the shims you have available, your going to end up with a clearance of either 0.18 or 0.23


0.18 is inside the spec, and 0.23 is just barely outside of the specified window of operation, but either one would be fine in my book.

well turns out the feeler guagers i used wearnt accurate..

i tested them with a micrometer and what was supposed to be a 0.08 showed up as 0.20 on micrometer...

i recomend checking your feelers accuracy so you dont waste your time

Ok here's the deal. . 008 of an inch is equal to .20 mm normally both of these values would be marked on the blade but in most parts of the world inches don't exist so the blades would be marked in mm only. I've seen a lot of things but a miss marked feeler gauge is not one of them..... Most of the service information is listed in both values in the service manuals. Sounds like you have a metric mic and some inch marked blades

Figure out which marks are in inches and sand them off with steel wool so you don't get confused.  Use metric only as the bike is all metric.  I also take out the relevant blades and put the rest away.   Makes the process easier.  


Unfortunately Hotcams shim kits only come with shims every .05 mm.  2 boxes with a range of 120 to 240 x .01.  I've never opened the box with the thicker shims.


Yamahas come from factory with shims every .01 mm.  But when I've looked in the parts fiche they only show every .05.  Too bad.  It would be easy to get valves spot on centered up if we could get them every .01


.18 is in spec but since valves tighten up it will be too tight before shimming to .23 would. 

When I check my valves I work in inches, much easier than Millimeters in this case. intake clerances in inches is 0.039 to 0.065. I will run my clearances on the loose side rather than on the tight side. You are looking at a range of only 0.003 in adjustment. You can either measure the shims in a kit or use a inch millimeter conversion from the internet. As for your mike giving you a different reading than what was stamped on the feeler gauge I would look for the fault in the mike. As for a measuring instrument Harbor Freight sells great electronic digital calipers on sale for around $10.00, and they are accurate. You can order packs of five shims from your dealer from parts unlimited, most of the shims in the Hot Cam $80.00t you will never use

thanks for all the help guys

i ended up using different feelers that were in mm so its easier my clearences are out both exhaust by 0.01 so ill shim it next month cause im plannin on riding this weekend and dont wana wait for shims...

also 1 more question

what causes valves too tighten?

Edited by jackiefresh69

The valve face starts to wear, which allows them to sit closer & closer to the cam, reducing the clearance. And they might stretch too from usage.

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