what keeps rave valves from hitting the piston/rings?

[foulmouthfool]

The reason that I ask is that my gtx was running bad after I replaced some rave parts....bad bellow and melted cap. It had horrible midrange and it was hard to get the rpm's over 5000, felt like it was dragging an anchor. If you hit a wake and the rpms spun up it would take off like a rocket though.

I was just about to go back through the carbs when I decided to check my rave valves because I didn't do a very thorough job of cleaning the ports that the valves ride in. What I found was that the new cap that I bought, when screwed all the way down on the rave valve stem, basically pulled the valve into the open position and made it stick there. You could not work it up and down at all. I unscrewed it a few turns so that it would work up and down like the other side and went riding. It ran great.

I haven't ordered another cap yet and wanted to make sure that I wasn't going to drop a rave valve into the rings by having that cap screwed out too far. I just tried to eyeball and mimic the movement of the other one.

Thanks

 

[Dr Honda]

You could....


If the the valve isn't threaded in... the RAVE could hang down, and contact the piston/rings. It's not pretty when the Rave crashes into the engine while it's spinning.

 

[foulmouthfool]

so it IS the cap that actually controls where the valve stops? I better screw it down a little bit just to be on the safe side until I can get the correct cap. I really don't know how I got the wrong one.......

 

[Dr Honda]

It's not the cap... it's the bellows under the cap. The red adjustment screw only set's the spring pressure.

(I may have miss read/understood your original post)

 

[foulmouthfool]

I'm using the wrong terminology when I say cap, I mean the black plastic thing that the bellows attach to that also have threads the screw onto the valves. One of them, its like its too long and when I screw it all the way down, it tightens the valve up against the housing so its basically stuck in the up/open position. In order for it to drop down at all I have to unscrew the "cap" a few revolutions in order for it to move as much (up and down) as the other valve assembly. I know, my descriptions are about as clear as mud.

 

[spx800]

yes, tighten that black cap that the bellows are attached too by hand as tight as you can. i know from the factory, on both valves those caps were tight. they are not in the open position because if you pull up on the cap, simulating when exhaust pressure opens the valve you will notice it will still pull up farther.

 

[foulmouthfool]

thats what I'm trying to say, that when tightened down it will NOT allow ANY movement. I can take the whole assembly off the head and try to work the rave valve, there is absolutely NO movement unless I start to unscrew it. NONE

 

[spx800]

ok yes that should not happen. like i said, when i cleaned mine i tightened them down by hand as best i could, then used a socket for a 1/16 of a turn and i still have movement. did you re-install your valves correctly? the guillotine should face downward towards the exhaust.

 

[Chester]

There is a collar on the shaft of the valve that rests against the cylinder to prevent it from hitting the piston. The cap that screws on should be tightened snug on the valve. Take it all apart and see what's wrong.

Chester

 

[DnE1800twin]

If properly installed a rave valve should never hit the piston. thats why they are cupped and shaved in a direction that follows the contour of the cylinder wall.
chester is correct, there is a collar on the valve that keeps it from falling into the piston.
it doesnt make sense that ur "cap"(sometimes called a rave valve piston) does not allow any movement when screwed down.
check for proper installation. make sure the bellows is seated correctly.
good luck.

 

[silver z]

im not great with the terms but i just went through mine and i have somthing for you to try.
When i was putting my valves in after cleaning everything they slid up and down fine. then when i put the aluminum piece that bolt to the cylinder on, one side was fine and one side was hard to move up and down and would stick up. I loosened the allen heads and it moved fine... it was pulled a little to the side when tight and was binding. I held it centered then tightened it. works great now