Bought a EU -01 YZ 125 with broken big end bearing, need help deciding if it as 2001 or earlier

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Hi guys, I'm new here and bought a have 2001 a month ago and the engine is almost down in pieces, need the flywheel puller that's ordered and the parts needed for the rebound of the engine. I'm also ordering Haynes YZ manual as I think it will be a good buy for me.

Anyway, the VIN strarts with CE08CE I think... on the back of my cylinder there where some mechanic had written with a marker pen -01 125. It seems like there have been a major failure before, as the head has small dents in it, and the cases are clearly not the same as the one with the VIN is much much smoother in the inlet and crank case. 

Engine VIN is E111E I think, or something very similar to that.

It has a white Airbox and floating front brake, I've read on other threads here that that was a new thing for -01, is it?


Fast help would be much appreciated so that I can order parts as soon as possible.

BTW, here a rebuild with wiseco crank, all seals, new main bearings, new ring and all new  gaskets cost about 500$. Just the crank at Yamaha was 1,200$ at the local Yamaha centre so you all should count yourself as very lucky! ;)


Thanks for help! I'll post other threads soon as I'm at the beginning is going to post the cases for a smoother flow and have complete HGS system. I really would love to have a 144 but I guess that will cost me insane money as everything is more expensive here, and I also guess sending head n cylinder to the U.S. would cost way to much too... So I'll, be doing what I can on my own and that's the cases for better flow and matchporting it to the cylinder. 


I much appreciate any help! Thanks!

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Thanks! MV00 is printed on the cylinder. He sold it to me as a -02, I was just searching for any cheap 125, I was lucky to find this one so cheap, as all other out for sale were 90 something bikes, with different problems, I paid ~500$ for it, bikes are more expensive here so it was a good deal as i will be having a nice mechanically fit bike for half the price similiar yz 125 goes for, just a bit more work but working with 2T is fun. I also have a 69cc race scooter i ported and built that puts out 23,5hp on the wheel with variomatic transmission, made a 7,63@121km/h at 150m drag strip, so its a feisty little machine!


I have owned a yz 125 -97 back when I was competing, so it's nice to have something similar but with different upgrades. This bike won't see much track time, I'm going to use it as woods/fun/asphalt bike :) I probably need to gear it a bit, to get some more top speed out of it, and some new more off-road like tires as mx tires on asphalt is no fun at all. I am thinking of bore it out to a 134, that's possible without messing with the case? I need it to be able to restore to a 125. 

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*Swedish sorry thumpertalk*

En OEM vev kostar kanske 10 loppor hos en Yamaha återförsäljare. Men går köpa betydligt billigare inom EU. Betalde runt 350 euro för min OEM till yz250. Just saying. 

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3 hours ago, MathiasJK said:

use it as woods/fun/asphalt bike :) I probably need to gear it a bit, to get some more top speed out of it

Careful if you plan periods of sustained wide open throttle.     These aren't road racers...



Edited by mlatour
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Yes, I know, been there, done that in my youth. The asphalt part of it is more to get to the fun trails and roads. A mx is far to soft and the tires aren't worth shit on asphalt anyway. For that, I got my 69cc road racer :) A complete replica of the scooter's they race in the Malossi cup down in Italy and Spain. 


Veven kostar 8k från Yamaha i Sverige, vilket inte är ett alternativ alls när det går köpa Wiseco för 2,100 i Sverige, har för mig Packningar etc även följde med då. Det blir wiseco för min del, kanske OEM är lite bättre, men med rätt underhåll bör ju även Wiseco hålla, hojjen kommer inte att tävlas med eller plågas på liknande sätt. Några varv på bana blir det säkert, men det är mestadels en lek hojj. Euron är dessutom uppe i 10kr så OEM i EU är ändå 1,5ggr dyrare. Men tack ändå! 

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