What year yz 250 pistons work on the tri z?

[Darius1502]

Does anyone know what year yz 250 pistons work on the tri z. I am trying to find a cast piston like oem, not a wiseco.

[tecat-z]

83-87 are the ones.

[Darius1502]

I've heard the YZ piston does not have the ports cut into it? While the Tri Z piston does? Does the Yz piston need to be modified or it is install and go?

Who is running a YZ piston their Tri Z?

[tecat-z]

If it concerns you, lower the floor a "bit," otherwise run them out of the box. Tri-z pistons draw a bit more at low rpm's. Nothing to be concerned about whatsoever. When Wiseco stops producing Tri-z pistons, everyone will eventually run YZ style anyhow. Similar to Tecates in a sence, cuz Tecate pistons are no longer made by Wiseco, and haven't been in a long time. KX's work the same, so one style fits both.

[Darius1502]

Cool thanks...when you say lower the floor a 'bit' what do you mean? Are you running one in your Tri Z? Any noticeable performance differences?

I've done some searches here and others have said you need to run the YZ sleeve.... just trying to make sure I do the right thing.

[El Camexican]

If you are concerned about this there are still NOS pistons on ebay for Tri-Z once in a while. You may have to wait, but you should find one eventualy.

[Darius1502]

Well I found some NOS Tri z stuff...but heard the YZ pistons make it scream. Just curious find out.

[El Camexican]

Well I found some NOS Tri z stuff...but heard the YZ pistons make it scream. Just curious find out.

I won't argue with you, but I did a lot of reading before I concluded what I was going to do to my engine, and I never came across anything about a YZ piston. If you want a screaming Z look into the Wrench Reports mods. There is a guy called Mosh on here that seems to have a lot of Tri-Z knowledge. You may want to ask him about that.

[Darius1502]

Good point. I think I am settling on the Tri Z piston anyway. Thanks man!

[Mosh]

Ronnie, who was the power squeezer of the Z engine, talked to me at depth about the YZ piston.
I dont recall the exact specifics, as Ronnie often inidated me with so much info, i forgot the specifics by now, but the window designs between the stocker and the YZ piston do make a difference.
Tecate-Z advice seams to be right in line with what Ronnie talked with me about.

http://www.3wheelerworld.com/showthr...ri-z+yz+piston