what year YZ piston?

[honda380]

looking to go with a yz piston top end, anyone know which year(s) to use? also, are they flat top pistons? also, what special requirements are required to run the piston other than a spacer plate? Corey

[Honda 250r 001]

its not really a good idea. get a differ cylinder or a new sleeve. cobbled up **** is not the way to go.

[C-LEIGH RACING]

Originally posted by honda380
looking to go with a yz piston top end, anyone know which year(s) to use? also, are they flat top pistons? also, what special requirements are required to run the piston other than a spacer plate? Corey


86 model YZ250.
That YZ pistons not flat top though.
Spacer plate for the YZ piston set up & under a stock TRX Honda cylinder, 2.5mm

Your top end, is it set up flat top right now, because if it is, the pistons probably a 97 year or up CR250R piston.

Neil

[regg187]

Originally posted by Honda 250r 001
its not really a good idea. get a differ cylinder or a new sleeve. cobbled up **** is not the way to go. I totally disagree I have known many people with the yz piston set up and they run great, or else how could this have gotten around. If you need a reference 001 call Billy Pointer the owner of QUAD TECH and ask him his thoughts on this set up when I used to ride with him he had this set up on one of his Quads, more than 1 if I remember correctly. Many other guys in the ATV racing industry also had this set up including test riders for 3&4 wheel action and a couple of supercross riders, granted motor work for them is all free , but they still ran it and, it ran well. If you have a 1 off cylinder that could never be replaced than maybe rethink this but if it is just a stocker waiting to be moddified definetly consider this as a great option. just use a shop that is familiar with doing this mod!
as soon as my setup needs a rebuild I will be going this route, money for nothing I can't afford right now, since it ain't broke, I'm not gonna fix it. But when it is time fix it ,a yz piston will be inside!!!!!
I'm sure C-leigh must know the how tos on this mod !!!!!!

[regg187]

C-leigh you must typ[e faster than me LOL

[C-LEIGH RACING]

Originally posted by regg187
C-leigh you must typ[e faster than me LOL :D

:D :D :p lol,,, no, look at the time the replys went in.

Anybody can type faster than me.
I make enough mistakes with one finger, lord knows what it would be like using both hands.

That ol 86 YZ piston set ups been around many years.
I know since the mid 80s its been used. If you were lucky enough to of had a Curtis Sparks 265 engine along that time, for sure it had the YZ piston.
Later on, some went to the 97 year & up CR250R piston, but the build had to change because of the flat top piston design.

One thing about the YZ piston, that made it a choise of most builders, it went up to a 70mm size, which would make the engine over the 265cc size, but you could slip it in & unless your engine was protested, nobody ever knew it was to big.

You use that 70mm piston, good midrange port, a high compression domed cool head, say around 220 lbs or higher compression & some real good race gas & can hurt quite a few big bore guys feelings. Got to know how to work that left foot though, shifting those gears where the meat of the power is produced.
Neil

[honda380]

thanks for the replies. i think ill get the yz piston and try it out. ive heard of the sparks engines running it and heard good things from other people as well. again, thanks for the replies. Corey