550 engine questions

[MRA 927]

Hello all! I need some info from the experts. I currently roadrace in Colorado (MRA) with a hybrid race bike. I took a Honda RS 125 GP chassis and inserted a CRF 450X motor. It is very fast and out corners anything on the track, I still can't beat the 250GP bikes. So I have purchased a slightly larger Honda RS 250 GP chassis and plan on putting in the SXV 550 motor.

Here are my questions:
1. What kind of hp and torque #'s can the engine produce?
2. Can or is there anyone who makes a 600cc kit?
3. Will the mx and sx internal tranny gears interchange?
4. For motard racing are the cranks getting lightened?
5. Any air box changes or aftermarket air boxes?
6. Who makes the best aftermarket exhaust and ECU?
7. STM makes a slipper clutch, is there any other brands?

The engine is tiny and extremely light, and is no bigger or heavier than a stock 250 GP twin. The guys I race against say a well tuned 250 GP will be around 75 hp. That is my goal I think 75 hp with the torque advantage will be competetive.

Thanks, Jeff Winter

MRA expert # 927

[PhilG]

Nobody does a 600 kit, there isnt enough stock in the liners to do it.

nobody has tried yet as the MX bike is too new

Alice Racing has GWR lightened cranks to good effect

Pipercross Filter from Alice Racing is a must.

Silmoto are good and crash proof.
ECU needs tuneboy to get the best out of it

Adler do one , STM seems to be favourite, i prefer the Adler

Your HP expectations are achieveable , we are working on a similar project here, but until its finished , we wont be saying as its not ours, we are just offering support for the motor.