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Valve Clearance

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Hello!

8 hours ago i checked, (0,12 & 0,09) and shimsed my INtakevalves. I also replaced the hotcamshaft with the orginal cam. Now, 8 hours of normal driving later i checked them again: 0,09 & not even 0,03 :thumbsup:.

Manual says; IN 0,16 +/- 0,03

Im very careful/accurate with the airfiltercleaning (denicol filterclean, then warmwater with some detergent. And ofcourse, between every ride normaly, and in the middle of a ride when its needed.

My bike is an CRF450 -04 with original valves (titan?). And as i told you ( if matters?), before i had the Hotcam, and now the original. Always easy to start the engine, in all conditions.

And yes my quastion; Is it normal, i mean 8 hours?

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Once the valves go to zero clearance, they will wear out very quickly if you shim them. At that point to need to order parts since replacing them is just around the corner.

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The same thing happened to me. I shimmed the left intake 3 or 4 times before I replaced the valves. I would lose 0,08mm about every 5 hours. When I finally took the head off, you could see the left intake valve was sitting lower in the head than the rest of the valves. I've had the bike for 4 years and I estimate around 200 hours so I can't complain.

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You said you changed the cam after you checked the clearances? Did you check the clearances again after changing the cam before you buttoned up the motor?

The shims for the Hotcam and the stock cam will be different. Try putting the Hotcam back in. Then see what you get for clearances.

ben

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The same thing happened to my '04 CRF450R. When my intake valves went out of spec, I reshimmed and they were out of spec again after 3 rides.

Time for new intake valves. I put in the Kibblewhite stainless steel intake valves and springs. Never had a problem again. I have read that the Ferrero valves are even better than the Kibblewhite.

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The same thing happened to my '04 CRF450R. When my intake valves went out of spec, I reshimmed and they were out of spec again after 3 rides.

Time for new intake valves. I put in the Kibblewhite stainless steel intake valves and springs. Never had a problem again. I have read that the Ferrero valves are even better than the Kibblewhite.

The key is to replace the valve springs with new springs rated for the material of the new valves...SS springs for SS valves, etc.

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You said you changed the cam after you checked the clearances? Did you check the clearances again after changing the cam before you buttoned up the motor?

The shims for the Hotcam and the stock cam will be different. Try putting the Hotcam back in. Then see what you get for clearances.

ben

Yes, i checked the clearance after i installed the original cam, and it was okey. Dunno what kinda valves it is now, but i think you got a point here. They maybe suited for the Hotcam.

However, i order some new aftermarket steelvalves today, but delivering first on monday. So one shims more for the weekend race.

Do i need any special tools to install new valves? In the manual there are a lot of them, eg. "spring compressor tool" .... dont have :thumbsup:

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You said you changed the cam after you checked the clearances? Did you check the clearances again after changing the cam before you buttoned up the motor?

The shims for the Hotcam and the stock cam will be different. Try putting the Hotcam back in. Then see what you get for clearances.

ben

you are correct. different cam is going to take different shims!

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