Everything2Stroke Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter #1
Hey guys, well my brothers finally going to have a big CP Power Valve Sphinx build for his 89 TRX-250R and I'm a Banshee guy (Trail/Dune Ported 535cc Power Valve Cheetah) and I'm not real familiar with the Big Bore and Stroker Setup's for the 250R so I was hoping I could get some input from the guys that know.

He's going with a stroked Power Valve Sphinx for sure. We both recreationally trail ride and play around with the 4-Chokes mostly and we both run the KOI 200ft/300ft 2-Stroke Trail Quad Class at a lot of the local county fairs. I'm having a 10 mil Trail Ported 535cc Power Valve Cheetah thats has a Crank Work's Billet Stroker Crank with custom machined 115mm Billet Rods that's set up for 100LL Av-Gas built by K a N Powersport's as we speak with all the best parts and my brother's wanting to build a similar Trail Ported Power Valved Sphinx for his 250R. Both Quads have the Clutch/Transmission Upgrades and Suspension Upgrades needed to handle these bigger motors.

So can you guys tell me the biggest stroke that can be used with a set of stock machined 250R center cases and still be reliable? I know that OEM Cranks and Hot Rod's are the two most popular cranks used on the 250R but IMO a Crank Work's Stroker Crank would be the best choice if they build them for the 250R.

Secondly what bore would you suggest? From my own experience I have found motors that are kept as close to "square" as possible usually perform best for the all around type of riding and racing we do. Would a 370cc PV Sphinx be a good reliable power plant? We both want big ass reliable motors with gobs of usable power and torque. If you guys could give me your opinions and input it would be greatly appreciated.
 

·
Registered
Joined
·
49 Posts
Discussion Starter #2
Nobody?

Surly somebody can tell me how big of a stroke you can use on the 250R without getting into reliability issues.
 

·
Registered
Joined
·
104 Posts
What did crank works say?

If you build it and the bottom does fall out, you would be on the phone with them. I'd go with what they say if your having them make it.
 

·
Vendor
Joined
·
1,500 Posts
How thick is the crankcase? You can measure & answer your question.
Trenching; the machinist term is counter boring. The people who do this kind of work are the one’s who have done the job & know.
 

·
Registered
Joined
·
205 Posts
One phone call is all you need. Pete knows more about these CP cylinders and engine builds, then everyone else combined.
Make the call, you will be sold!

Pete Schemberger
Hybrid Engineering
2715 NW 6TH PL
Cama, WA
98607
360-281-2274
 
1 - 5 of 5 Posts
Top