View Full Version : Broken Raves
05-20-08, 11:28 AM
Hello everyone. I'm brand new to the forum but it looks like there's a great bunch of people here.
I have a few concerns that perhaps some of you could help with.
I own two 1997 GTX Seadoos. While cleaning the raves this spring I noticed on one machine both rave guilotines are broken. This isn't the first time. Where does the broken piece go? Sucked out the exhaust? Why do they break?
I clean them once per season and they are always black and sticky. (Our season here just outside Toronto Canada is short. June to Sept.) I use Amsoil synthetic and I thought synthetic would help with sticky raves. Also, I always eventually get oil blow-by from the raves as sooner or later one of the belows will come partly off its mount. Do I have the red plastics screws down too far on the spring? The shop manual says even with the top of the black housing but the dealer has it screwed down farther and they said leave it alone.
05-20-08, 11:37 AM
Welcome to the seadoo forum Keith. This is a friendly place with lots of active members very eager to help out. I personally use only seadoo oil. I don't ever have any problems with rave valves...well they do need cleaning annually. Usually if the rave valve breaks it will go out the exhaust valve. I would get new RAVE valves and switch to the recomended seadoo oil. I bet it solves your problem.
Use High quality low ASH API TC Injector oil.
Do Not use NMMA TC-W, TC-W2 or TC-W3 outboard motor oils or other ash less type 2 cycle oil. Avoid mixing different brands of API TC oil as resulting chemical reaction will cause severe engine damage. Never mix Mineral or synthetics oil together.
Never use fuel containing more than 10 % alcohol,( Methanol or Ethanol) as severe damage will occur. The minimum of 87 octane is recommended for most engines.
I hope this helps out.
05-20-08, 11:48 AM
Any thoughts on the reason they break or why the bellows come partly off?
Thoughts on if the red screws are screwed down too far?
05-20-08, 12:04 PM
well the bellows might have a weak spring that rapes around the bellows bottom. I would replace them. It is possible that they got stretched out while cleaning them.
The red knob is just an adjustment for the pressure to raise or lower the valve. I would start with the adjustment even and adjust it a little till it seems to rev at a regulated pace...not to abrupt.
05-20-08, 02:23 PM
Thanks Karl. I'll buy new springs and put it back together.
05-20-08, 02:29 PM
Keep us posted on the progress.
05-22-08, 03:19 PM
The only progress I have to report is there won't be any progress to report for a while. $500.00 for a small bag of parts and have to pick up at 4 different dealers to get all that I need.
05-22-08, 05:17 PM
Man, I hope I don't have to get my parts from the same source as you. Those guys sound like they are robbing you!......:ack:
You can get a RAVE rebuild kit for about $25 bucks from http://www.sbtontheweb.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=S&Category_Code=1997sxp. Then, go to www.babbittsonline.com, click on the tab for parts. When the page opens, on the right, you'll see a parts list search. Put in your RAVE part #, which is 290854352, and click search. You'll find the valves for about $81 dollars a piece.
Your RAVE problems......if this is a recurring problem, there has got to be other issues outside the bellows. There is a small hole, which is used for the combustion pressure of the cylinder to push up on the bellows to open your rave as needed to increase your exhaust gas flow, which is what makes your ski efficient. I'm wondering if your getting an excess amount of oil (and you know oil and rubber aren't a really good mix) in the bellows that's causing it to deteriate. If this IS happening, then I'd ask you how much oil your using from your injection tank on a normal day. Your rotary shaft chamber seals could be going out, causing excess oil into your bellows cavity via your crankshaft and pistons. If the carbon build up is really bad after such a short period of use, then like Karl says, look at the type of oil your using also.
The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performace, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.
One last thing. If your raves guillotine valves have broken and you don't see them. Again, like Karl said, they have problem gone out the exhaust. But now, if they didn't make it all the way out, they could be partially blocking your exhaust system, increasing the back pressure, blowing out the RAVE bellows. Especially if both are affected. This is a very likely cause to the bad carbon build up and oil residue in the bellows.
But to replace both your RAVE's and two rebuild kits is but $212 dollars.
Keep us informed as to what you find.
05-27-08, 04:01 PM
Thanks Seadoosnipe for the information. Sorry I took so long to reply, I've been away on business.
You're probably correct with $212.00. My $500.00 was for two machines. Even if I was to order from your source at $212.00 X 2 for $424.00 I'd be $500.00 by time I shipped it up and paid Canadian duty, taxes and brokerage. However, it would save me running around to different sources.
06-26-08, 01:51 PM
Finally have all the parts to do all four raves on both machines.
I think I've figured out why the guilotine valves keep breaking on one machine. This is hard to tell until you have the new parts sitting side by side with the old parts.
The threaded shaft of the guilotine fits up through a cast housing. This is the housing that bolts to the engine with the gasket underneath. If the hole in the cast housing is worn too much, combined with a worn shaft on the guilotine, the guilotine will wobble way too much inside the engine causing it to vibrate against the side of the exhaust port thus breaking pieces off.
Also, the shaft of the guilotine is screwed into a plastic piece called the piston. The bellow is connected between the piston and the cast housing. When the guilotine vibrates side to side too much is causes the piston to move side to side which allows the bellows to pull off of the piston or the cast housing. Now you've got an oil mess inside the engine compartment. Not to mention a rave that is now not working properly.
When you slide a new guilotine into a new cast housing it becomes instantly apparant that the other parts are worn beyond what you should use.
The mechanic said there's usually no problem if a piece of the guilotine breaks off as it will be sucked out the exhaust before any damage occurs. However....... if the guilotine breaks off below the shoulder (this shoulder prevents the guilotine from hitting the engine piston) the guilotine will fall down against the piston and cause scrapes on the the piston. In the worst case it could now break off and slide on top of the piston......... and you know what will happen to your motor now.......... CRUNCH!
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