Replace or re-use

A guy asked me to have a look at his YZ450 -03. He told me that he had run it hot and that the oil was like rubber?? He had striped it apart him self and now want help. After a quick look today I can see that the timing chain are crap, also the sprockets have small marks after the chain. Top end looks ok.

Cylinder and piston have very small, but still vertical scratches. He also told me that the 4: th gear is jumping from time to time.

I know it would be best to replace all these parts, but it would cost around 20 000SEK = 2800 USD for only the parts. :lol: So any suggestions? Maybe he could use the cams with only a new chain, but can we do something about the cylinder? Can we hone it (not sure about the name in English:confused: ) and use a new piston? If he can use the cylinders and cams it would save him over 1200 USD

Gears and fork needs to be replaced so I can’t see any savings there.

Or shall I suggest that he put it out on eBay?

The value for a -03 in good condition her in Sweden is around 4000 USD :confused::crazy: .

Thanks for any advise


Oh yes, now you are asking your self, what does a new 450 cost :lol:

?????? 11 000 USD (inkl. all tax and a service kit)

I would suggest that you try running a "bottle brush", or spring ball, hone through the cylinder before you decide it's bad. If that cleans it up, use it. The cam sprockets are probably OK (I can't see them, of course), but the bigger concern is the crankshaft sprocket. That wears faster due to it's smaller size and heavier load, and since it's cut directly on the left crank axle, when it's worn out, it means you need a crank.

For the 4th gear problem, you need the 3rd gear pinion, the 4th gear pinion, and the #2 shift fork.

OK, thanks.


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