yz piston.

[number5]

I seen a auction on ebay that reads yz piston 83-87 for Curtis Sparks or Paul Turner TRX 250R motor setup. This for a special decked cylinder?

[C-LEIGH RACING]

It might could be if that was the type of mod on the cylinder. Normally though, that piston is used on a 250r long rod crank & then a 2.5mm spacer plate under the cylinder so the piston will come up flat with the deck.

I've seen some weard Sparks stuff though, had a stock R cylinder one time, had so much metal removed from the base & then the ports cut so high couldnt anything else be done to the cylinder, porting couldnt be changed. Cylinder was ported for just a little above bottom end output & that was it. Talk about something being made into one off, that was one.
Neil

[number5]

I guess that would keep you at 265 then. I think it was a 68.5 or 68.2mm

[x.system]

Originally posted by number5
I guess that would keep you at 265 then. I think it was a 68.5 or 68.2mm

I've got 5 or 6 paul turner motors that are all setup for the yz piston and 2.5 spacer. We ran these before they came out with the thicker spacer plate so you could use honda pistons. Most of these were also nikasil sleeved and pt also took them right to 265 so we were still legal at the ice nationals. Anyone remeber pt's names for these? most of mine have hyperdyne and a couple have max overdrive national hyperdyne on them.

[number5]

So this makes it a bottom end motor or top end. I would think if your ice racing your motor is screaming.

[CorvetteZ06]

Originally posted by x.system
I've got 5 or 6 paul turner motors that are all setup for the yz piston and 2.5 spacer. We ran these before they came out with the thicker spacer plate so you could use honda pistons. Most of these were also nikasil sleeved and pt also took them right to 265 so we were still legal at the ice nationals. Anyone remeber pt's names for these? most of mine have hyperdyne and a couple have max overdrive national hyperdyne on them.

I had one of them hyperdyne motors, i remmeber it screamed!! do you still have any?

[x.system]

Originally posted by number5
So this makes it a bottom end motor or top end. I would think if your ice racing your motor is screaming.

All of ours were ported for top end wide open throttle. I started out racing b class but all my friends I used to race against raced A so I jumped up to A the next year and we all pretty much ran the same setups. The only things we were trying different were different pipes back then. I settled on a ct high rev but we tried them all.

[x.system]

Originally posted by CorvetteZ06
I had one of them hyperdyne motors, i remmeber it screamed!! do you still have any?

Yes, I have 5 or 6 top ends yet, all hyperdyne, just different levels of port work. The last one I was running about 3 years ago was the national hi rev max overdrive. I blew that one up due to a waterpump in a one hour race. After I pulled that motor I had RB Racing build me a new 250 and will never go back to PT. My RB motor being a 250 put out just as much if not more HP than my last 265. We used to run these cylinders till they would blow then send them back to PT for more work so we always had a few on hand. The ones I have left over now all need work, either new coating or new sleeves. You gotta remember, back then you could call up PT and get a cylinder and everything you needed for under $500 shipped plus you could pick up bottom ends right from the dealer for cheap. Our local dealer used to keep half a dozen motors on hand at all times ready to go, they also used to build complete race bikes, at least my dealer did but then again he was also a racer. I just noticed our old dealer just listed one of his leftover race bikes that was last run in 96 at the nationals. I also know where theres one that hasn't been ran since around 89 and you should see all his extras. I've been wanting to buy him out for a couple years now.