The bike in this link is the one they got the engine for the Banshee from. http://www.stannakajak.com/skalmanmc/rd350/

 

Do you think a stock RD350 makes 75HP? That's a pro built bike!
A moded Shee can do over 75HP.

 

I think he may have been talking about the Stock 47-50 rear wheel horsepower it says it originally has? [img]i/expressions/face-icon-small-confused.gif[/img]

 

THEMOOSE
I’m talking about the 47-50 stock HP and the power valves.

 

Banshee ports are almost identical to the RD/RZ350. The only thing the RD got was the YPVS (Yamaha power valve system). The powervalve doesn't help peak power. The YPVS is very primitive and as was said, they stuck very often. Yamaha realized this and is why the didn't powervalve the shee. I believe this system was pressure operated instead of centrifugal, but I have never looked closely at the powervalve system.

 

And just to stoke the '01 Raptor tranny fire, notice the following sentence:
"SRW:s race engine produce +75 bhp (that is almost 90 hp on the crank!) using almost only modified original parts - original clutch, original gearbox, original crankshaft, original cylinder head, etc."

Now how come the street bike tranny the '01 raptor has can't handle half that HP in the dirt without exploding? I think we got robbed!

 

More links:
"electrically operated power valves"
Port maps.

 

The bike engine that the Raptor uses made 48-50 horses.
SRZ660 1999

<a target=new href="http://www.custombike.org/bike_yam.htm">YAMAHA SZR660'96 on, 659cc w/c DOHC single
50hp</a>

OV-16

 

Banshee ports are almost identical to the RD/RZ350. The only thing the RD got was the YPVS (Yamaha power valve system). The powervalve doesn't help peak power. The YPVS is very primitive and as was said, they stuck very often. Yamaha realized this and is why the didn't powervalve the shee. I believe this system was pressure operated instead of centrifugal, but I have never looked closely at the powervalve system.


what a load of bull.....................

The stock RZ exhaust is 2.5 to 3mm higher than a stock banshee, ask your tuner what plus 3mm exhaust port timing does for peak HP............

Having ridden a powervalved banhsee with RZ top end you will not believe how torquey they are as the exhaust port timing is retarded compared to a stock banshee at lower revs this also increases the effective compression ratio also helping torque. The power delivery is miles smoother yet has about another 1000 rpm on top over the shee.......

Not only does an RZ kick a Banshees butt for peak HP, it cleans it up for both peak torque and torque spread.

Stuck valves, only on high mileage engines running cheap mineral oils..........

The reason Yam didn't use it on the Banshee was they where to CHEAP............

See my web site for RZ shee info.......

Kiwi