rz350 topend on banshee...

[bradyray]

I just bought an 87 banshee that has a YPVS rz350 top end on it. Got it home took off the head cause I didn't think it was running right. The right piston has metal melted on top of it. But the bore is perfect....no scores scatches or gouges at all. Smooth as a baby's a**. So I thought sweet ill just get a new piston. I buy a digital micrometer and go to gauge the cylinders and they are different sizes. By 1.25mm! What should I do? One is 64.25 and the other is 65.50. Should i re sleeve the 65.50 jug? If so how much would that run? If it makes a difference I live in Iowa.

[Coupelx]

I just bought an 87 banshee that has a YPVS rz350 top end on it. Got it home took off the head cause I didn't think it was running right. The right piston has metal melted on top of it. But the bore is perfect....no scores scatches or gouges at all. Smooth as a baby's a**. So I thought sweet ill just get a new piston. I buy a digital micrometer and go to gauge the cylinders and they are different sizes. By 1.25mm! What should I do? One is 64.25 and the other is 65.50. Should i re sleeve the 65.50 jug? If so how much would that run? If it makes a difference I live in Iowa.

 

pull them off and give them to me.

[bradyray]

Yea that would be good for you huh......lol

[blowit]

Yea that would be good for you huh......lol

 

 

If your 65.50mm bore is still good, I would recommend boring the other to match and run 65.50mm pistons. No sense in resleeving unless you really have to.

[volvo63']

I just bought an 87 banshee that has a YPVS rz350 top end on it.

 

 

 

You need to throw up some pics.

[Nightmare]

can u run those without using the pv's just like non pv cyl's????? i only ask cause i got a ypvs top end also??????????????

[bradyray]

You can run them either with the pvs locked open or locked closed. Opinions vary on wich way to go I heard closed was better so I'm gonna try that way. And wouldn't it be better to resleeve the one that only has one more overbore left rather than bore the one that is only on its 2nd overbore??

[Nightmare]

im with blowit on that one, not unless u have to.

[Starwriter]

You can run them either with the pvs locked open or locked closed. Opinions vary on wich way to go I heard closed was better so I'm gonna try that way. And wouldn't it be better to resleeve the one that only has one more overbore left rather than bore the one that is only on its 2nd overbore??

There is no "open or closed". It's a rotating spool that raises and lowers the exhaust port height. If you lock it in the lower position, your upper RPM power is going to suffer drastically. If you lock it in the upper position, it will kill your low end power. The following RZ350 parts are necessary to make the power valves work properly.

 

Servo motor

Servo controller

Stator

Flywheel

CDI

Voltage regulator

Battery or battery eliminator

Associated wiring

 

If you don't have all this stuff, you would be better off to sell the RZ350 cylinders and buy some Banshee cylinders.

[mike0chek]

that cant be good for the crank havin different size pistons lol

[zach45]

y not... they do it on jet skis alot.

[mike0chek]

y not... they do it on jet skis alot.

 

i learn something new every day lol

[2strokenit]

Is there any way of removing the rotating spool from the RZ cylinders so the port timing is fixed, just asking because I also have a RZ engine and looking at my options.

Thanks.

[Coupelx]

I cant say 100% but usually the port layout is such that its designed for when the power valve is completely open and its a compromise in any other position.

[Starwriter]

Is there any way of removing the rotating spool from the RZ cylinders so the port timing is fixed, just asking because I also have a RZ engine and looking at my options.

Thanks.

 

If you removed the spool, there would be a very large chunk of the port missing. As Coupe mentioned, when the spool is in the up position, everything is one with the universe. When the spool is rotated down, the port is kinda funky, but it makes the motor think the top of the exhaust port is lower, to improve low rpm power.