tr-z / yz pistons the same??

[garyn]

Hi , just joined , all the way from sunny scotland ,anyway , ive just stripped down my 85 tri-z250 , someone has snapped off the bottom half of the piston ,ie it has no skirt ,is it ok to run it like this ?? or would i be able to put in a yz piston ,any help please

[Swamp trike]

I always use yz pistons for my tri-z, and you should'nt run it with a broken piston

[Youngrasher]

Which year yz piston do you use?

[garyn]

so the yz piston is ok to use ? without the need to change sleeve etc ??

[Blown 331]

I will most likely be buying a piston for my TRI-Z as well. Some more info on this would be great. Any benefits?

[Swamp trike]

Yz 250 has the same piston between 83-87 and that's the one I've been using
You can also use the top end gasket kit within those years, the only difference is the gasket for the powervalve-cover wich you can throw away!!

[3WW Star-Yamahondaman]

I will most likely be buying a piston for my TRI-Z as well. Some more info on this would be great. Any benefits?

Yes the 83-87 YZ Piston seems to have a tad more umph in the TRI-Z .. i use the PRO-X Brand .. they last longer than the FRI-CO's ..

[Blown 331]

Yz 250 has the same piston between 83-87 and that's the one I've been using
You can also use the top end gasket kit within those years, the only difference is the gasket for the powervalve-cover wich you can throw away!!

Since the YZ has a powervalve is is possible to use the whole top end?
I think I read the YZ also has a thinner head gasket.

Yes the 83-87 YZ Piston seems to have a tad more umph in the TRI-Z .. i use the PRO-X Brand .. they last longer than the FRI-CO's ..

I did a search before you replied and some people say you have to use the YZ sleeve, any truth to that? And I read that the YZ pistons don't have the "windows" in the skirt. What is their function and does it matter going to a piston that does not have them?
My jug is already 1mm over. So are you saying I can just get the next size up 83-87 YZ piston and it will go right in with out any other issues or problems?

[DeePa]

running a yz prox piston in my tri z now...

no special sleeves or any of that stuff.

you can swap whole yz cylinders and heads but you need to have the linkage in the clutch cover. there is a thread on here how someone modded the cases and installed the powervalve linkage in the bottom end, and put a yz top end on.

only one year of the yz top end has the same intake angle as the tri-z...think its the 83 year.

[garyn]

just found and ordered a wiseco tri-z piston for it on evilbay ,got my bore checked ,all fine , surely though it couldnt have been doing the bike much good running it with half a piston ,didnt have anything below the pin .Bike went not too bad though , had a wee bit of a flat spot but once it cleared it seemed fine .

[3WW Star-Yamahondaman]

Since the YZ has a powervalve is is possible to use the whole top end?
I think I read the YZ also has a thinner head gasket.




I did a search before you replied and some people say you have to use the YZ sleeve, any truth to that? And I read that the YZ pistons don't have the "windows" in the skirt. What is their function and does it matter going to a piston that does not have them?
My jug is already 1mm over. So are you saying I can just get the next size up 83-87 YZ piston and it will go right in with out any other issues or problems?

the TRI-Z piston "de-tunes" the motor for the "ATV" .. i even got better results when i used "RD-400" Piston's in the Banshee i used to have.. just like TRI-Z-YZ .. there the same size .. just the Windows are diff. ..
like said ... the "83" YZ cyl. will fit .. you can ax 03orangeshee "Nathan "about it .. he has one

[SYKO]

in the same note... Yamahondaman can attest to ... the first time he met me my 85 R ran like a maniac... found out when I tore it done (first after I bought it) it had a CR piston in it... like the YZ it has no windows in it either... my R ran hard with it.. even though it had a leaking head gasket and a troublesome carb on it that weekend.

[brrcuda]

Very informative - thanks. I know what i will get for my next Tri-z piston now...

[garyn]

so how long should i run in the new piston for before giving it the beans .

[MTS]

The holes in the piston aid cooling, and sometimes act as a transfer for your boost port above the intake.