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Ok so I decided to check my valves to see if they are in spec after 11 or so months owning the bike. Now I'm not too experienced with 4 strokes however, the exhaust valves are all ok but the inlet valves are too small. I don't get why the gap is getting smaller. The valves are getting closer to the cam shaft. I don't get why it's doing that? Shouldn't the gap be getting bigger? Then what do I do next? New shims using that formula?

The gap is getting smaller because the face of the valve is wearing down so the gap becomes LESS not more , as the valve wears the face sucks into the seat , as it does that , the gap to the shim becomes less , so now a THINNER shim is needed , the shim size stops at 1.20 , so if the gap is less than allowing a 1.20 shim , then you will need a valve job/new intake valves , with the shim you have in there , measure the clearance , the gap should be 0.006 +/- 0.001

If a 0.004 feeler gauge goes in , then either use the calculator , or try the next size smaller shim , , keep trying a smaller and smaller feeler gauge till you get a gap , take that number and note the difference from where you should be , that is how far the valves have moved , the shims come on 0.050 gaps , so 2.0 , 1.95 ,1.90 , etc, (in a HotCams Shim Kit) , they start in the 3.0's , but when choosing you have to compromise on the gap you should use Digital Calipers to check the shim size , if you don't have any , you can get a cheap one a Harbor Freight , its what most of us use

http://www.harborfreight.com/6-inch-dig ... 47257.html

You want it as close to 0.005 as you can get when your done , but as i mentioned , once you get to a 1.20 shim , then your on the last run of the valves , and its literally a matter of a few hours before it will zero out again , and the top end of the engine will have to be torn down , and no matter what , once the valves start moving , then its just a matter of time , part of the price paid for high performance dirt bikes , the valves are considered "Wear Parts" , just like your chain and sprockets

Hope that helped explain it some

JimDirt wrote:The gap is getting smaller because the face of the valve is wearing down so the gap becomes LESS not more , as the valve wears the face sucks into the seat , as it does that , the gap to the shim becomes less , so now a THINNER shim is needed , the shim size stops at 1.20 , so if the gap is less than allowing a 1.20 shim , then you will need a valve job/new intake valves , with the shim you have in there , measure the clearance , the gap should be 0.006 +/- 0.001

If a 0.004 feeler gauge goes in , then either use the calculator , or try the next size smaller shim , , keep trying a smaller and smaller feeler gauge till you get a gap , take that number and note the difference from where you should be , that is how far the valves have moved , the shims come on 0.050 gaps , so 2.0 , 1.95 ,1.90 , etc, (in a HotCams Shim Kit) , they start in the 3.0's , but when choosing you have to compromise on the gap you should use Digital Calipers to check the shim size , if you don't have any , you can get a cheap one a Harbor Freight , its what most of us use

http://www.harborfreight.com/6-inch-dig ... 47257.html

You want it as close to 0.005 as you can get when your done , but as i mentioned , once you get to a 1.20 shim , then your on the last run of the valves , and its literally a matter of a few hours before it will zero out again , and the top end of the engine will have to be torn down , and no matter what , once the valves start moving , then its just a matter of time , part of the price paid for high performance dirt bikes , the valves are considered "Wear Parts" , just like your chain and sprockets

Hope that helped explain it some

Wow that is the best answer, thanks. The left valve is the smallest, I measured it at 0.0035 and the right is 0.004. Now I just use the formula
A=(B-C)+D to get my shim size.

Correct , it will tell you what shim to use

I just use a micrometer and measure the existing shim, and replace it with a shim that is .002 thinner.

You can find our shim calculators and spreadsheets:

http://crfsonly.com/howto/index.php

There are how-tos as well on checking and adjusting your valves.

Ken