powervalves

[Project300EX]

I've been having a hard time finding powervalves for my project motor. I know you can plug the holes and run without power valves. My question is how would this affect the performance of the motor? I'm guessing I will have a little less low end torque. If so would it be horribly bad? And anything else? I will trail it a bit, but mostly just road and field riding. I would still like some pretty good torque though. Also any tips or guides on how to plug everything? Thanks.

[GPracer2500]

What engine/cylinder?

[400exrider707]

I'm guessing 88 RM250 since thats the motor in his frankenstein...

[Project300EX]

Yeah. I like to have never found a cylinder and the one I found didn't have the powervalves. It sucks when I bought the bottom end I saw all kinds of parts for them, but now I can't.

[Project300EX]

Anybody?

[Project300EX]

Any insight?

[GPracer2500]

The only insight I can offer is the experiences I've had with riding bikes with non-functioning (or not functioning properly) PV mechanisms.

One was a 1988 CR250R. The valves (there were two on this engine) were not connected properly and bounced around (open/closed) out of sync with how they should have been. If kinda felt like it was jetted all wrong. But it did have plenty of power up top. I think at high rpm the valves where being held open in the position they should be in. At medium and low rpm the valves were all over the place. It was rideable but definitely didn't feel right.

The other was a 1995 CR250R which uses a single flapper valve to control exaust port timing and a pair of sub-exhaust valves to change the exhaust system volume. In this case the mechanisms were stuck in the shut or low rpm postion. This bike actually ran ok like that. If you didn't really know how much power the engine should be making you might not have even known anything was wrong. But it did feel flat and slow reving. Perfectly rideable--just a little soft. I bought this bike like that and I don't think the previous owner had any idea the PV mech wasn't hooked up right.

Not sure how that helps, but it's all I've got!

[2muchquad]

Keep looking on ebay,you'll have some come up eventually.The powervalves make the motor think the exhaust headpipe is longer than it really is,therefore producing more torque.You will want to have operating powervalves though for the best performance of your engine.If you ran without them you would compromise the powerband(where you want it) of your motor.You can get lowend without powervalves to a point but then your motor wouldnt rev out as strong up top due to it being built for lowend.The magic of powervalves;)

[Project300EX]

I'll keep looking, but so far it's not looking good. I know I'm going to have to run a longer pipe to fit the quad anyway. So if I can't find anything maybe that will help a bit. I've heard from a lot of people that the Suzuki pvs of that time suck anyway. I guess I'll just have to play around with gearing if I can't find anything.