4 stroke life span

I have an '04 yz 450 and LOVE IT!!!! I've put a lot of time and money into mods on it - PWR low boy radiators, Storm Cycle link, Factory Connection revalve, Triple clamps, exhaust and so on. I keep reading about how rebuilds consist of new case halves and new cylinders and new heads and how it's about $2000. I would think that with proper maintenance, oil and filter changes, along with top end and valve jobs the cylinders and heads and cases should last a long time. I realize if you let your motor go bad things happen but are the new thumpers destined to have the motors "grenade" and need to be completely replaced? Acording to MXA nothing over about 5 years old will last. I would like to keep my '04 and someday race it in a vintage class. Is this realistic?

The short answer is, that will depend on you as much as the bike.

riding style, maintnence, etc. Me and my main riding buddy have been riding "modern" four strokes for 5 years now. (03yz450,04rmz250,05crf250,08yz250f,08yz450) Never a single "catstrophic" failure. Just the appropriate maintnence at the appropriate times.

There's something to be said for grabbing a case of beer and spending the weekend in the garage wrenching on 2-3 bikes with freinds. It gets done quicker too.:smirk:

Ive never heard of modern 4stroke cases being "Worn out". Seen lots broken, never wore out

I rode a 2002 CFR450R for 2 years and sold it to a guy who rides twice as much as me and maintains his bike like a mechanic in solitary confinement; that's all he does when not riding.

Thing starts on the first or second kick and runs like a fine watch. And if a CRF can do that a YZF most certainly can!

So whats the standard with most of you guys? On a very well maintained bike ridden moderate to hard, whats the intervals you like to change components? piston, cam chain, bottom end, ??

On a very well maintained YZ450 you should get 80hrs. on fresh top-end assuming riding bike moderate and nothing else is wrong.I believe racing vintage class with well maintained YZ450 is very realistic.


Edited by motox1160

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