Best version of YZ250?? (pre 2002+)

[Iandork]

I'm on CL contsantly looking for a yz to swap into my 05 frame... there are 3 located locally within my price range. Choices are an '86, '93, and '96..

My plan was to transplant, work out the bugs, then rip it down to make it pretty.. At that time i'd look to do a big bore, trouble is i don't see a lot of choices for these years readily available.. And the ones i have found are from some dark corner of the country.

Is newer always best??

 

[dksix]

I had this conversation with a long time Yamaha mechanic yesterday. He said the 93 was a good year for the YZ.

 

[toytech]

I think the 96 is the newer style motor with more hp than the other 2, check into it. easier to get parts for also.

 

[YZ Otis]

I'd pass on the 86 ... the early 90's motors where good motors for the money in my opinion ... I think they changed from cast iron sleeve to nikasil in 92 ... the only big bore kit I know of for the older motors (late 80's to early 90's) was the Ohlins/Noleen 360 kit ... used a Ohlins nikasil cylinder & head with a small power valve, a YZ400 piston and a YZ465/490 rod ... The cylinder & head are very hard to find, one is hiding in my Blaster ... I looked into this years ago and ended up having a cylinder resleeved for a Kawasaki snowmobile piston and stroking the yz250 crank to get around 310cc for our Outlaw Kart.
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Good Luck & please share lotsa pix & videos of your build!

 

[J Llamahead]

I have a line on a 92 yz 250. Engine. I hear the top end will fit on the Tri-z250 engine I think I want the power valve system? The Tri-z transmission has 6 forward gears and I suspect more favorable gearing for the blaster than yz engine .
Any advice on this subject will be much appreciated .
YZ Otis ya out there ?