Rave valve adjustment

[finatic@aol.com]

I have a 1997 GTX with the 787. I was told improperly adjusted rave valves will cause issues either at low end or wide open. My ski seems to run good but it seems to be missing a few RPM at the top. It will only hit about 6400 RPM. What I found when inspecting the rave valves was that the red adjuster was screwed all the way in. I backed them out until they were even with the top of the black cover they are located in. Was that the correct thing to do?

 

[kmarts]

I have a 1997 GTX with the 787. I was told improperly adjusted rave valves will cause issues either at low end or wide open. My ski seems to run good but it seems to be missing a few RPM at the top. It will only hit about 6400 RPM. What I found when inspecting the rave valves was that the red adjuster was screwed all the way in. I backed them out until they were even with the top of the black cover they are located in. Was that the correct thing to do?

That's the factory setting so yes technically it's 'correct'.

All the adjustment does is change at what point in the RPM range your raves open. I believe the tighter in they are turned the higher RPM they open at, with the opposite being true for turning them out looser.

I don't know about what 'performance' affects this has, i think the adjustment is more to suit the riders style to where they like the power band shifted, Top RPM will stay the same regardless of the adjustment.

 

[GGuillot]

Check that water valve on top the muffler, according to the service manual that explains the function of it, you can loose some RPM's on the top end if doesn't work properly. Has something to do with dumping less water into the exhaust system at the top of the powerband, therefore extending a few more RPM on the 787.

 

[kmarts]

For the water regulator.

Turn it in all the way and then turn it three turns out. This is the factory setting and with the rave caps flush, is where it should be set.

If you want to screw with the rave tuning, I've read you can turn the water regulator adjustment in the OPPOSITE direction you adjust the raves.

 

[mikidymac]

The water regulator adjustment should not be messed with. The RAVE caps on the engine can be messed with all you want and it is fun to see how they change when the power hits, just make sure they are adjusted the same on both cylinders.

Your loss of 500 rpm on top end suggests a bad water regulator.

 

[kmarts]

The water regulator adjustment should not be messed with. The RAVE caps on the engine can be messed with all you want and it is fun to see how they change when the power hits, just make sure they are adjusted the same on both cylinders.

Your loss of 500 rpm on top end suggests a bad water regulator.

Out of curiosity can you explain why you shouldn't mess with the regulator?

I've read on other pwc sites where people have replaced the WR with a fixed jet, or have talked about adjusting the regulator like I had mentioned.

I know what the manual says, I just don't understand why it's adjustable if it shouldn't be adjusted.

 

[etemplet]

So my having the water regular adjusted flush at the top is not the correct setting. Hmmmmm..... The effect would be that the regulator shuts off the water a bit prematurely? I'm guessing this isn't going to have much of an effect on performance specifically top end performance which is for me... I'm looking for RPM anywhere I can get it.

 

[mikidymac]

I don’t think anyone has figured out why the regulator is adjustable other than maybe it’s for fine tuning of different models.
Yes you can hard jet it but that was mostly for racing where you really are only concerned with top end performance as the regulator provides good top and bottom performance.