Somebody told me that in 1989 TRX250r's came with power vavles stock from the factory. Is that right?

Could someone also please explain how a power vavle works, and what kind of gains you get with it.

Thanks

 

NO Honda didnt have a PV in 1989 on TRX. late,zubbeyboy

 

Lateralus is correct, TRX's did not come from the factory with a power valve. Although thanks to the aftermarket we can have them now.

The purpose of a powervalve is to provide more bottom end power like a four stroke. If you have ever ridden a two stroke you may know that when you slowly accelerate (lightly applying the throttle after releasing the clutch) there is very little power until the motor hits the RPM it was tuned for. Most of the time its the midrange.

The powervalve is actually a valve which stays closed at low RPMs to provide more power, then when the motor hits it's tuned spot the valve opens up and lets you experience the joys of two stroking[img]i/expressions/face-icon-small-smile.gif[/img].

By the way there are two types of powervalves that I know of. The first is a vacuum operated valve which opens and closes with the pressure inside the cylinder and cases. The other is a mechanical valve which has a linkage that opens and closes it.

The vacuum operated valve is what you see on the TRX's because there isn't anything in the bottom end to operated the linkage. The mechanical valve is what you see on most dirt bikes and the ever popular Suzuki 500 quadracer.

 

i think the 89 CR250's had PV's , the only quad i know that had them was the Tecate,kawi put them on those which what made those things scream or at least helped

 

the quadzilla had a "powervalve", but my understanding is that it wasnt a powervalve to the sense that it didnt adjust the exhaust port hieght like traditional powervalved do but rather in some way adjusted the harmonics of teh pipe

 

The 87 to 92 250 quadracers had powervalves also.

 

Your friend needs to do more research.[img]i/expressions/face-icon-small-wink.gif[/img]

 

Thanks guys. I just bought my first 250R last night. It's pretty much stock, except for the FMF pipe and silencer. It's in great shape, except the frame needs to be painted of powder coated.

My friend was telling me it had a powervalve. I was looking at & thinking, there is no way there is a PV on it. I just wanted to make sure before we argued about it. PV's are on the exaust manifold ( the flange that the pipe bolts to) right?

Anyway power valve or no power valve this thing hauls, and it handles so much better than my banshee. I'm really happy I found it.


THanks Again