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03 CRF450, New topend. Few ??

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Hi, new to these forums. I bought a used 03 CRF450 last summer and I'm looking to rebuild it before this season since I dont know how many hours are on it. What would be the best piston to put in? I was thinking of the 04 since its a little higher compression, then I read that the Wisecos were the way to go. What do you guys recommend? This will be the first time taking it apart, do I need anything special for the valve adjustment? Shims? Is there any know problems or areas I should look closely at? Thanks for your time, Ryan

:)

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can you buy stainless intake valve springs only or do you have to buy both intake and exhaust , if so where

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I'd put new valve springs in the thing regardless of it needing a valve job or not. When they're brand new the springs are just barely adequate. When I do the topend on mine, Im putting RHC springs in it (with the stock valves)

As far as shims go, you just have to measure the thing and find out where it is. If theyre fine, theyre fine. If your getting close to zero...well, it may be time for a valve job. Cross that bridge when you come to it...

An 04' piston is supposed to be 12.1:1. When I do mine, Im going to put a 12.5:1 JE or Wiesco in.

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I just got my head back from RHC today. Here's my new top end:

new SS valves both sides

new springs both sides

new '04 OEM piston

new OEM everything else (gastkets, etc.)

There really no special tools if you're handy. I'm an idiot so I've purchased every purpose-built tool I could find to do the job and they all worked great.

MP valve spring compressor

MP multivalve tool

MP piston puller (didn't need it on my red 450, but did on one of my blue 450s)

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Thanks for the help guys. I'm thinking I'll go with the Wiseco 12.5:1 Piston kit, OEM Gasket set, Valve shims(now that I'm a 4 stroke owner, I should have theese in the tool box) and new springs. Hopefully thats all she'll need. I'll give everything a good looking over when its apart. :)

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One more question, Will going with the 12.5:1 affect the jetting at all? I'm decent at jetting 2 strokes, but I'm clueless on the 4 strokes.

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One more question, Will going with the 12.5:1 affect the jetting at all? I'm decent at jetting 2 strokes, but I'm clueless on the 4 strokes.

It should not.....

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