4 hour re-ship 05 crf450r

I checked the valve clearences on my 05 crf450r and was shocked to find how far out they were after 4 hours use.The exhaust and decompressor were fine but the intakes were tight and required shims two sizes smaller to get them in tolerence.The bike is used for supermoto and has had the oil changed every hour.The first two oil changes with semi synthetic then to fully synthetic .The is standard with no exhaust or engine mod's but was running rich when i picked it up. Has anyone had the same with their bike , and how often would you recomend checking the clearences. I would be very greatful for any help ,as this is the first bike i have had with this type of valve setup.

Oil change every hour??? WOW ! I thought I was bad. I would have to change while riding if that was the case. They may be tight due to the little amount of time you have on the bike. Just my .02 I am sure some of the 450 wizards on here will know for sure.

My completely non scientific observation is that the longer you hold the thing close to the rev limiter the quicker your valves will go with oil having very little to do with it. I've got to believe that Super Motard has the bike close to the rev limiter a lot. Just my opinion and based on hear say.

my 05 had 20 hours of supermoto on it and 400+ dyno runs.the valves never budged.

5 hours in i went to a RHC cam wich is easier on the valve train.

Some move a little with break in... some don't. Some keep movin... and some don't. Some move after a few tens of hours.... some don't. Some last for 100s of hours... some dont.

The "distribution" of valve life is all over the map. So its almost impossible to say what the norm is. Seems like ya gets what ya gets and thats about it.

A wide and seemingly random distribution suggest that there is more than one factor involved. Possibly many.

So if and when yours go out make sure you get someone who truely knows how to cut seats on M/C heads to do the job. Put in good valves (SS is tougher) and springs and then hope for the best. Thats about all you can do.

Going to SS valves seems to move the distribution to the right (increasing time).

Now these are just my observations from watching CRF450 forum since 2002.

Maybe we should get a statistics database started here on TT. You'd have to make sure people only contributed if they had accurate data and not guesses. It would be nearly impossible to weed out the jokers though. To get decent statistics you'd need at least a few 100 accurate data points.

IT's very likely they were out of tolerance from the factory. Mine were, not by much, but enough that I reshimmed them after breakin.

i haven't had any problems on my 05 250F and i ride it pinned alot, my 04 tightens up sometimes (20 hrs minimum between shimming's) but i ride it even harder.

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