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02 crf450 valves...no clearance?? Help

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Does this make sense? I am checking valve clearences on 2002 crf450 I just bought. It ran ok...HARD to start...poor low end "putting" around. I figured valves were out of adjustment. I cannot get ANY feeler guage in the intake sides. The exhaust side is a tiny bit out, but not bad. I am sure I'm at tdc. marks line up, lobes point rearward, exhaust rocker lobe free wheels, etc. If they are this far off, where do I start to shim. What clearance number would I use for its present condition? Thanks.

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If the intake valve clearance is truly at zero clearance I think that you should just accept the fact that the valves are done and get on with the appropriate repair.It is my experience that any loss of intake clearance more than .003 means that the hardcoat has worn off the valve and recession of the valve face has happened.What this means in simple terms is that sealing surface of the intake valve is no longer straight but "cupped" and no longer has a hard coating on the surface,the valve will continue to loose clearance quickly after a reshim sometimes in as little as one hour.I'm sure that this is not what you want to hear but save some time and aggravation and at least have the valve seats recut,new intake valves and springs and seals installed. To really fix the root of this problem as I see it on an 02 you must purchase a complete air box assembly for an 03 or 04 to fix the air boot to air box sealing issue that the 02 has or at least a Pro Seal,MX Bones or Twin Air 02 sealing kit,but the 03/04 air box is really the best way.cheers

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I just finished a valve adjustment today. Basically, you've measured a zero tolerance. The proper clearances are...

INTAKE 0.006in +/- 0.001in or 0.16mm +/- 0.03mm

EXHAUST 0.011in +/- 0.001in or 0.28mm +/- 0.03mm

Measure all your valve clearances(write them down). Disassemble the cam assembly. Read your shims(write these down). Go to your honda dealer and buy new shims (bigger or smaller) to get to the tolerances indicated. If you don't have a manual and your not a crack mechanic, buy a manual or take it to a shop you trust.

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Thanks Guys,

I just got done pulling the head off. Is there a "trick" to getting the stupid valves out so I can inspect things? I am taking to the dealer in the morning, but I wanted to get it naked so I could look at myself and save some labor time for the dealer.

Thanks again for your help.

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To remove the valves... put a deep well socket over the valve spring retainer and tap it with a hammer. Bingo, keepers pop out. Again TAP don't beat the valve retainer.

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same thing happened to my 02 450R, you need to replace the valves. I opted for the kibblewhites SS valve kit. Unless you are going to lap in the new valves yourself, who ever you take the job too will need the head anyway, so just take the head to someone who knows how to install valves. Most auto shops are stocked with motor heads used to lapping valves in cars, and will usually help you out. If you find a performance shop specializing in small cars (the foreign 4-cyl cars) or motorcycles usually have all the hi-tech machinery and can do a professional job.

-Chuck

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The same thing happened to my son's '02 CRF. One intake had no clearance. Hard to start, etc.

Bite the bullet, get the Kibblewhites (valves and springs). I just got them last week from Thumper Talk Online shop, best prices! :banghead::banghead:

I am waiting for the seals to show up so I can take the head to my local motoheads (they are good) to put them in. I am also putting in a new top end.

So far I've spent about $458 just in parts ($302 for valves/springs, $156 for top end/gaskets). You can go with the OEM valve route and save, but if you plan to keep the bike for a while I'd get the Kibblewhites.

Cheers,

David

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Can you please tell me valve clearances for an '04 CRF450 and fork oil capacity and oil height? Thanks

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