89 CR250 Cylinder Fits On 250R

[NINJA]

Somebody gave me a blown up 89 CR250 engine and just for kicks I wanted to see if the cylinder would fit on 250R cases, it does! All you'd have to do is use the base studs from the CR and the piston. The ATC head fits no problem. Of course the powervalve doesn't work, but you could have an adjustable cylinder with this setup. Any thoughts or input on this?

[tecat-z]

Many things to consider..... Is bore and stroke the same? Pin to crown height, exhaust fitment etc. Think red rider did a functional PV cr topend. But required lots of intelligent creativity. Making PV inoperative would probably stifle any kind of low rpm torque output. The Pro-x cylinders are superior for most of us i believe as a big power producer.

[x.system]

Its an easy mod, PT has been doing it for years before the pro-x cylinders came out. I wouldn't just slap one on though, theres more to it than fitting.

What do you mean by adjustable?

http://i42.tinypic.com/2jg854z.jpg

[Red Rider]

Many things to consider..... Is bore and stroke the same? Pin to crown height, exhaust fitment etc. Think red rider did a functional PV cr topend. But required lots of intelligent creativity. Making PV inoperative would probably stifle any kind of low rpm torque output. The Pro-x cylinders are superior for most of us i believe as a big power producer.You are correct sir! Bore is different, but the stroke is the same.

[NOS_350X]

I got 4 of them cylinders,

Been waiting till i get a R that i want to put it on.

ESR makes a PV blockoff kit. that will solve that problem

Your exhaust flange is much smaller so you got to weld on a smaller one to your pipe.

And i belive you need a 3MM spacerplate.

[NINJA]

Cool info on all this guys. I didn't know PT had done this, so I take it he has the powervalve blocked off also. When I said adjustable, I meant you could play with setting the powervalve where you wanted it at. Yes, bore is different at 66.4mm as compared to the R at 66mm. Stroke is the same though. I'm not actually going to do it. I was just curious as to whether it had been done before and what all it would actually take to make it work. Red Rider, please elaborate on the drawbacks of this setup. Thanks for that pic X-system.

[Red Rider]

Red Rider, please elaborate on the drawbacks of this setup.When the powervalves are fully automated, and working as designed, there are no drawbacks, other than the in-depth work involved to automate them. I tried the cylinder with the powervalves locked in place, but still adjustable for different conditions, and I hated it. I found the powerband to be very "peaky" & narrow. If you want to check out my website, I explain the various phases I went through with the CR cylinder.