Removal of Rave Valves on 96 XP??........

[Banditsteve]

Hi All,
Just wondered if anyone has ever removed the rave valves on a 1996 XP and blanked off the hole with a metal plate and what sort of difference to the power and general running this made to the engine?
I know what they do and how they work in theory but just wondered how much ACTUAL difference they make?
I know it should have them in an ideal world but they are chucking oil out and sometimes blowing the bellows off and need replacing but I have just had a £900 bill for a new starter and some gaskets and seals and loose baffle removed from exhaust and and and and so I dont want to spend any more on it!!
Thanks Guys,
Steve :cheers:

(Btw - Sorry but I put this in the general discussion forum as well by mistake - Sorry)

 

[Bills86e]

When the raves open at appr. 4400 rpm it changes the horsepower band to increase.

If the RAVE valves are dirty it will not rev up correctly and could be causing your problem. On 787 engines the red adjuster knob should be flush with the top of the cover, for 951 engines it should be fully tightened in the cover bore. at that setting the pipe is dried out somewhat allowing the engine to rev higher.Changing the adjustment will only change the amount of water that is injected into the headpipe. Having said that, if you were to actually completely pinch off the water line from the regulator to the headpipe, the exhaust chamber would overheat and melt the hoses. That's about as catastrophic as it would get. The engine itself (or the cooling to the engine) would not be affected at all.
pressure line runs from....... pulse fitting under carbs to check valve to rave solenoid, rave solenoid actuates raves around 4500ish rpm by opening pressure to diaphragm. closes by solenoid opening to atmosphere on most all 951's. remove, it should move freely in housing. if not inspect and clean. the shop manual has some spew about no parts wearing, but diaphragm can tear, piston shaft can wear and not seal on oring causing leak/black oily goo..... it takes very little pressure to actuate valves, pull line and pressurize with pop off or blow hard. Clean any accumulation of sand out of the small hose going to pipe belly & make sure there is no blockage in the fitting with A wire or pointed tool.
The rubber parts are cheap and well worth the time & small investment. Bills86e

 

[Banditsteve]

Thanx Bills86e but I think I may have described my fault wrongly. I meant the 2 exhaust rave valves on the engine and not the exhaust rave valve thing on the exhaust muffler. And I have got the 787 engine which as far as I am aware have no solenoids or whatever. I thought they just worked on exhaust pressure but correct me if I am wrong!! And my valves are clean they just chuck oil out due to worn stems and guides but I dont want to buy any more cos I have spent far too much on it already, hence the question as th whether I can just remove them completely and what difference it would make? Hope this makes sense now? Thanx again, Steve

 

[seadooya]

you'll have no bottom end.

 

[Banditsteve]

No bottom end...........

No bottom end or just a bit less bottom end?
Just to confuse the issue I took the top off the rave valves today to clean some of the oil up after yesterdays run and the bellows had blown off but what I can't understand is that it was pullin harder at the end of the day than it has ever done, both bottom end and top end and that was obviously without the rave valves working!!?? Am I being dumb here? I was under the impression that as you went faster and the engine revved higher the rave valves overcome the spring pressure and opened to effectively give you a bigger exhaust port but obviously in my case yesterday it went better with the rave valves closed, I assume giving a smaller exhaust port? Is this because it was creating more back pressure? Can somebody explain this to me cos if I am right I am thinking I could maybe turn the rave valve bodies by 180 degrees so the airway is blocked and the rave valves stay closed and I could get away with not replacing them? I appreciate that in an ideal world I should replace them but this thing is a bloody money pit at the moment!! Thanks Guys. Steve :cheers:

 

[flip6]

Ok i was curious so did this recently on a 98 xp.

If i deactivated raves then ski wont go top speed

If raves fully open all the time then bottom end is really flat till about 4000 rpm then is fine till top speed.

 

[Banditsteve]

Thanks Guys, I will give it a whirl sometime. Steve :cheers: