pv engine vs non-pv engine

[rich.allen]

is there any difference in performance between a pv engine compared to a non-pv engine. are there any performance gains by having the power valves. i used to have a suzuki rm dirt bike that i think had that pv tech on it and while riding,once the engine reached a certain rpm that sob would take off like a bullet. i have a 1200gpr with the pv engine and while riding i don't notice that difference in take-off. i checked the power valves while working on the motor and they are in good shape and the servo motor is working also.

[Almost]

The PV's should open at 5,000 RPM, if you ride it with the seat off when you hit 5K you should see the PV's turn over. The PV motors have better low end performance apparently. 03-04 motors are best of both worlds EFI and PV's. After 05 they switched to a non PV motor.

[mikegp]

non pv for me. i got rid of the my pv engine long time ago, and i don't miss it a bit.

[JetEd73]

Skip the PV BS

I think the general consensus is that they are the most unreliable engine yamaha ever built...particularly the early models of the 66V

[Almost]

You should install wave eaters if they are not installed already. That will stop the PV pin from coming out and prevent your PV's from falling in to the cylinder. A must have for the PV motors.

[mikegp]

You should install wave eaters if they are not installed already. That will stop the PV pin from coming out and prevent your PV's from falling in to the cylinder. A must have for the PV motors.

i don't know what is the deal with the clips. i have seen two major damages , a big chunk of the valve break down and find its way into the cylinder, i have not see one pin fall out yet.

[Almost]

http://www.greenhulk.net/showthread.php?t=177749

If you ran without them more power to you, but it's a known fact that they help. If you have a PV motor you would silly not to have them. Yeah PV motors have problems, but it usually happens after wear and needing to be re adjusted. PV's don't just magically fall into the cylinder or come in contact with the piston there is a reason for it and it can be prevented. If you have wave eaters and make sure your PV's are clean and properly adjusted I'm sure you will have many trouble free hours.

[nunnink23]

Skip the PV BS

I think the general consensus is that they are the most unreliable engine yamaha ever built...particularly the early models of the 66V

Thats interesting that you say that. I always wondered the same thing. I am finishing up a total overhaul of a 1200pv engine, and for some reason I still don't feel like it will be reliable.

I didn't know that they switched to a EFI non powervalve in 05 like Almost posted above. That is interesting as well. What was the reasoning behind that?

I did ride a gp1200 and it was pretty quick, and in my opinion had more bottom end, but that's not a fair comparison because the gp1200 is tiny compared to the gp1200r.

[ctct2118]

Skip the PV BS

I think the general consensus is that they are the most unreliable engine yamaha ever built...particularly the early models of the 66V

I don't know where you get that from. After you put the pv clips they are very reliable.