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crf 250 valves

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I have an 05 Crf 250 that only starts by pushing. I checked the clearances and i got

INTAKE

L-.005

R-.00

EXHAUST

L-.011

R-.011

Everything is fine except my right intake and it has a shim size of 145mm

I believe 130 is the smallest. Is it possible that if i put a 130mm my valves could hit the piston with 30min of riding or will it take longer. I plan on selling it running but letting them know it has a problem.

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Your intake clearance should be 0.005 (0.12mm) so you have to reshim your right valve with at least 0.12mm less. You can try the 130 but you have to measure the clearance after installing because it might still be 0 mm or 0 inche. If you rode around for some time with 0 clearance the valve is probably burned and damaged so it should be replaced. The costs are about $100 for a replacement + installing.

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i put in a 135mm on the right intake and it is now .005 like it should be but when i tighten the cam caps and use an allen wrench to spin the cam the cam chain comes off from the bottom sprocket. The marks are all lined up and the timing is correct. Maybe i never put chain on corectly in the bottom sprocket idk i think i did, or is my chain guide bent?

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Chain came off the bottom sprocket when you were playing around with the timing. It happens all the time. Make sure that it's on before you start turning the engine over and make sure you release the timing chain tensioner also.

Now for the bad news. Once the stock titanium intake valves start moving, they don't stop. After you re-shim the right intake valve, it's going to zero out again very quickly. You'll be lucky to get another ride or 2 out of it before the same thing happens. You need to replace the intake valves and springs. You will need to have the valve seats cut so they are concentric with the new valves. Not have the seats cut will shorten the life of the new valves and give you a bad valve to seat seal resulting in loss of compression and power. If you're not a high level A-class or B-class MX racer, consider some good quality stainless steel intake valves.

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Now i got the cam and chain on good with everything lined up. How can i make sure my piston and valves don't hit before i kick it? Also when i move the crank with the allen wrench on the right side, once the lobes are pushing the exhaust rocker arm it almost gets stuck there or maybe its just that I'm turning it over with an allen and its real hard?

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I ussually use the kickstarter to rotate the camshaft, with the allen wrench you need too much force, if all is lined up and the chain is on the gears nothing can go wrong.

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Pull the spark plug out and use your hand with the kick start to rotate the engine. It's still a little difficult to do it this way once the decompression pin hits the exhaust rocker arm. Use a little more ass!

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