yz 250 big bore kits to a tri z?

[pcs]

are the newer yz 250 top ends much different from the tri z versions? ESR is finishing up some BB cylinder for the yz 250 in 325 and 345cc versions. maybe slap this cylinder to a tri z lower would make for a fun tri z to ride!
http://www.eddie-sanders-racing.com/product_p/yz%20345%20kit.htm

[volfan537240]

That would be awesome

[sx250heath]

The ESR kits are for more modern powervalved YZ motors

[christph]

Yeah, I'm pretty sure the ESR cylinder is for the current YZ motor, which is quite different. Now, you might be able to swap the entire Z engine for a new YZ. The rearward kicker would be an issue and probably other things you wouldn't know about until you tried it.

[volfan537240]

The op wanted to know if the newer yz jug would fit on a tri z bottom

[christph]

The op wanted to know if the newer yz jug would fit on a tri z bottom

The 80s YZ powervalve cylinder (not sure which years) could be fitted to the Z with some difficulty. The Z bottom end is actually the YZ bottom end so the missing parts can be fitted. There are threads on here about how to do it. The major problem with the YZ cylinder (aside from the challenge of finding the parts now) is that the intake is at an angle whereas the Z is straight back. I'm sure the modern YZ jug would be harder if not impossible to fit to the Z bottom end.

[pcs]

i thought the esr power valve kits for the honda 250r isnt mechanically driven and it looks like the same set up as the yz kit so i dont think that should be an issue or just run a non powerevalve set up. its not like a power valve kit makes any more hp.
also i wouldnt say its impossible to fit. ive seen ers honda kits on a lt250r lower end and cr500 liger cylinder on an lt500r lower end so i would say its more work to be done vs impossible.

[christph]

I just took a look at the ESR YZ cylinder and how the power valve is actuated is a little unclear. They have their pressure activated gate but then it looks like their casting preserves the option for the OEM mechanical gate. Yeah, if the pressure activated gate is an option then it might be possible. A 325 big bore kit for the Z would be cool. The intake looks to be straight back so that is not a hurdle. There are a lot of other issues of course. Do the studs match up? Would a Z exhaust bolt on or need major reworking? Would the stock Z crank work and if not, what would? It would be nice to get a hold of one just to check out the feasibility but at 800 bucks it would be a potentially costly experiment. I guest you could get a trashed YZ cylinder off ebay and check. I wonder if Eddie would be interested in looking into it? I imagine there are more than a few Z owners that would buy one if it didn't require too many major mods.

[volfan537240]

I'd be all over it

[pcs]

i agree with you on the as well chrisph. i would jump on a bb cylinder too if it was sold!