Fail. Rave Fail.

[DSchmidt54]

So i was wondering why i had a micro mist of oil accumulating on my exhaust header on my 787, the thing ran like a champ so i wasnt really concerned and i figured it was because i had it tuned rich (i figure it will last longer that way) well while reading a how to on tuning raves i noticed they said watch out for the spring when you release the cap.........and i was like "spring? mine has no spring?!?" <insert picture of cat here> and then i realized..........its spraying a micro mist because the raves are always open, also explains the semi-hard starts i have been having.

So i ordered some from tonka, anybody have any suggestions on where to set the caps (depth wise? ) what does turning them in do ?

thanks
Drew

 

[Strizzo]

you can set them where you want depending on your own preference, the "spec" in the manual is flush with the top of the caps, and i think 1 turn in from flush on the water valve. when i got my xp, they were all basically turned all the way in. at that setting, on my ski, it had good bottom and mid range power, and the last 20% of throttle from about 40 you can feel the raves open up and the ski jumps from 40-50 or so, then climbs slower up to 55. i tried them set flush, and while it still hit the same top speed, it took longer to get there and didn't have the same "punch" on the top end.

since you have a leak, i would also order a couple RAVE rebuild kits, with new gaskets, o-rings, and bellows to be safe.

 

[DSchmidt54]

yeah, i took care of the leak .........now im just waiting on my springs........so if i turn them in i will get better bottom end? alright, i can do that haha

 

[SabrToothSqrl]

nope. the rave's cant generate more power, they can only move the power band...

 

[Strizzo]

Dr. Honda had a good post a couple weeks ago on what the exhaust valve and the rave valves do, and how they each affect the power band. basically the RAVEs when closed effectively make the exhaust port smaller and open later, which improves bottom end, but costs power on the top end. that is why they open. when they are open, they allow more exhaust flow and better top end. the water valve controls the amount of water that is injected into the tuned pipe, which alters the velocity of the sound waves in the pipe. basically, wet pipe = slower wave, better bottom end, but reduced top end, drier pipe = higher velocity wave, and shifts the powerband towards the top end.

these two systems work in concert with the purpose of creating a smooth and broad powerband. if you've ever ridden a dirtbike with a tuned pipe on it, you know the 2-stroke feeling, kinda doggy, then when it comes on the pipe you have to be careful you don't flip over backwards. that sort of light switch powerband is what the RAVE and exhaust water valve are trying to reduce. if you get a smooth water day, you can go up and down through the powerband and kinda feel when the exhaust valve closes and when the RAVEs are opening. if you invest a bit of tuning time you can get them just how you want them.

 

[DSchmidt54]

Soo the more I turn in the screw on the pipe equals more water too it? Or less?

 

[Strizzo]

not more or less, when open, it flows x amount, then when it closes it shuts the valve to dry out the pipe. i'm not sure exactly if it closes completely or drops to a small amount just to keep the couplers from melting, but it is at least less.

you have to think of what a tuned pipe does for a 2-stroke, the exhaust pulse travels down the pipe, and reflects back toward the exhaust port. when the motor comes on the pipe, the reflected pulse is hitting the exhaust port right before it is closing, pushing some fuel/air mix that had come in the intake side and back out the exhaust side back into the chamber just before the port closes. more fuel/air, more power. the water in the pipe (actually the temperature) alters the speed of that exhaust pulse inside the tuned pipe. since at lower rpm the time between the exhaust port opening and closing is longer, the pulse has to be slowed down so that it comes back to the exhaust port just before it closes.

this is sorta similar to the variable cam timing that is now pretty common on most cars. by varying the overlap between intake/exhaust, and timing of both relative to the crank and ignition, the powerband can be shifted around, with the overall goal of making it broader than it would be with a static camshaft timing.

 

[summer]

The repair manuel will give you your stock settings for the caps.

 

[Dr Honda]

Dr. Honda had a good post a couple weeks ago on what the exhaust valve and the rave valves do, and how they each affect the power band. basically the RAVEs when closed effectively make the exhaust port smaller and open later, which improves bottom end, but costs power on the top end. that is why they open. when they are open, they allow more exhaust flow and better top end. the water valve controls the amount of water that is injected into the tuned pipe, which alters the velocity of the sound waves in the pipe. basically, wet pipe = slower wave, better bottom end, but reduced top end, drier pipe = higher velocity wave, and shifts the powerband towards the top end.

these two systems work in concert with the purpose of creating a smooth and broad powerband. if you've ever ridden a dirtbike with a tuned pipe on it, you know the 2-stroke feeling, kinda doggy, then when it comes on the pipe you have to be careful you don't flip over backwards. that sort of light switch powerband is what the RAVE and exhaust water valve are trying to reduce. if you get a smooth water day, you can go up and down through the powerband and kinda feel when the exhaust valve closes and when the RAVEs are opening. if you invest a bit of tuning time you can get them just how you want them.

Wow... I didn't know I was that smart. :lol:


Anyway... that's all correct. And... as an FYI... on my 96 XP... I run my RAVES all the way in... and my water reg at 3 turns out. This gives a nice, controllable low speed ride... but it is a little snappy up top. (right around 5500~6000 RPM's)

 

[LouDoo]

I run with my rave valves turned in from flush about two turns. I find that any less the ski doesn't run well at 40-50mph which is usually the speed at which I cruise. The water valve I leave flush, I really can't tell much difference by adjusting the water valve.

I hope you guys noticed that I used proper grammar above and I didn't say "the speed I cruise at".

Lou

 

[summer]

I hope you guys noticed that I used proper grammar above and I didn't say "the speed I cruise at".

Lou

So what do you want a cookie or something? :hurray:

 

[Strizzo]

So what do you want a cookie or something? :hurray:

its a big step for any kentuckyan, especially Lou.

 

[KyleB]

its a big step for any kentuckyan, especially Lou.

Hey Strizzo hows about leaving my fellow southerner along. He can't help he's from KY...the jelly state... ;-) :cheers:

 

[summer]

I have a neighbor who is originally from Kentucky...her license plate actually reads

KY FAMLY

Dont think I would have told that one. :lols:

 

[KyleB]

I have a neighbor who is originally from Kentucky...her license plate actually reads

KY FAMLY

Dont think I would have told that one. :lols:

:lol: well there ya go....

 

[LouDoo]

Question: Do you know what a Buckeye is?

Answer: A Kentuckian that ran out of gas on his way to Detroit.

Lou

 

[KyleB]

Question: Do you know what a Buckeye is?

Answer: A Kentuckian that ran out of gas on his way to Detroit.

Lou

Good one Lou. :thumbsup: Hey how's that '95XP 800 running? Did you ever make a deal on those two you went to look at a few weeks ago?

 

[LouDoo]

The 95XP 800, is running great, I did bring it home, it really doesn't need much except a good cleaning and a cover for the handlebars.

I had to let the 2 96XP's go, I really didn't want the hassle with the titles and besides I think I might be better of with one good ski rather than 2 crap ski's. I have found a 96XP in northern KY I may go look at. 96XP's are not in short supply, at least not around here.

Lou

 

[KyleB]

The 95XP 800, is running great, I did bring it home, it really doesn't need much except a good cleaning and a cover for the handlebars.

I had to let the 2 96XP's go, I really didn't want the hassle with the titles and besides I think I might be better of with one good ski rather than 2 crap ski's. I have found a 96XP in northern KY I may go look at. 96XP's are not in short supply, at least not around here.



Lou

I'd like to pick up another '96XP so I'll have a matching set but with all the other projects I have lined up this Winter I'll probably wait until next Fall. Unless I can get a really great deal and then just let it sit until I have time. :cheers: