Top End Rebuild

I have an 08 wr with about 5000 no so gentle miles on it. I raced a National Hare and Hound this weekend with quite a bit of flogging being done to the the old girl and now she's talking back. I'm getting a ton of oil out the valve cover breather into the air box. The valves were recently adjusted, some tight but nothing major. I knew this day was coming and I was just wondering what I was getting my self into. Still starts and runs fine just probably some ring seal issues and I'm not too sure about any valve leakege.

Curious, who else has done a top end and when it was all said and done what did you have into it $ ?


I found his post after searching. I got it all torn down and of course the Pro X piston kit is on back order from everybody. Looks like it will be a week or so.

Here's a thread from my 07 rebuild last year

This year I did the valves as well.

At a minimum you'll want to change your cam chain with that piston.

Spray brake clean in the ports and see if any leaks out the valves. Tell you wether you need to go in there anyways.

Turns out to be a bit more wounded than I had hoped...3 valves were pitted and the other two were hammered. New piston, ring and nickel sil (cylinder had two pretty bad grooves at the top). It's also getting a new cam chain and clutch. Needles to say, bike will be down for a few more weeks, just shipped the cyclinder today.

Edited by dez4ever

Maybe look at replacing your cam chain tensioner as well if it's done that much work.

From what I've heard they're not that expensive, but could cost you a whole heap if they fail.

I had my old 426 rebuilt after losing 5th gear and didn't replace the tensioner when the motor was torn down.

The bike ran fine for a 1000ks or so then dropped three inlet valves and took out many other things...

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