TriZ piston in a 250r?

[Ryah]

Can a TriZ or Yz piston fit in a 250r atc with a spacer plate? I've heard that you can fit some type of yamaha piston into a 250r with a spacer plate, if that's the case I may be able to get a few more bores out of my cylinder as the TriZ piston comes in larger sizes. Any info on this possible mod would be greatly appreciated.

[crackshot]

Yeah why bother with expense and hassle. Just get cylinder resleeved.

[Bryan Raffa]

the only problem i see with that is that the cylinder skirts would be extreamly thin and and run the chance of breaking one off and damageing the bottom end.other than that I have heard nothing on that.

[Billy Golightly]

Talk to Yamahondaman (Ronnie) He's done it before and word has it they run like a bat out of hell.

[TimSr]

You didnt mention what year 250R, but the liquid cooled R's go up to 3.5mm overbore (.140") when most max at 2.0mm (.080") overbore, and I cant imagine there being enough cylinder wall left for another bore after that, even if you did find a larger piston that "fit".

[Yamahondaman]

Paul Turner "Duncan Racing" has bored them out to a BIGGER Size like TimSr Stated instead of re-sleeving !!! i don't like the "re-sleeved" Cyl's because no matter how much you "Match Port" the NEW Sleeve .... it NEVER Seem's Right !! as far as .............. (SLOWER) ... And Like Billy Said .... .08 Over ATC,TRX Motor's are the same bore as the TRI-Z 68mm ... what i found out was like "Curtis Spark's" was that with an 1/8" spacer plate along with the "YZ" or "TRI-Z" Piston , the Motor is a 265 as long as you run the "LONG" Rod from the "88-89" TRX Motor's ...i have done "Short-Rod" Motor's with the "YZ" Piston and they GO !!!!
The only thing is that i take off .07 from the bottom of the Cyl. and the Bottom of the Piston... i have ALL of the Cometic Gasket No's and the "PRO-X" Piston No's
DON'T THROW AWAY YOUR .08 OVER HONDA CYL'S !!!!!!!

[Ryah]

Fill me in with the "short rod" details. I'm sure others as well as myself would love the details (ie what needs to be done as well as part numbers in detail). Heck a write up on it would be great. Maybe it could be made a sticky. Surely the increase in sales of TriZ pistons can only help the piston makers to keep producing them a little longer (I've got a TriZ too so this is of importance to me)

[x.system]

I have PT top end that uses a yz piston and 3mm spacer plate on a long rod motor. I've had this top end for over 10 years, got it way back when it was the hot setup. Its outdated now but still doable and a very strong pulling motor.