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Rave Valves

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jam38dd

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Thanks for the link!

I am female and have 1996 xp 787cc rotax engine. I thought i was getting a good deal $600. ski with trailer. $2,500 and two years later finally enjoying it a little. Discovered it needed a new/rebuilt motor. Im pretty intelligent and mechanically inclined. Orginally had stepson working on ski. He removed old motor and parts that the shop did not want left on engine for the core replacement. When the new engine arrived he hurried putting it together and didn't bother to go through the rest of the engine, i.e. carbs were dirty, didn't clean Rave valves and several other things I can't recall. I am now the mechanic. Proud to say that it is running pretty good. Followed the break in procedure last year myself to be sure it was done correctly. I'm confident I did it right. Last year it ran ok but still needed fine tuning and oil started seaping out of the pto (vavle closest to the rear of ski) rave valve. Starter solenoid went out at the end of the season last year. The ski was very hard to start and had to use starting fluid 95% of the time before it would start. Discovered it had the wrong sprak plugs, (bpr8es) not (br8es). Starts much easier 98% of the time. It had a hesitation at 3/4 throttle. I kept reading about the rave valves, how easy they are to clean and it should be done annually. When I would push the valves while still in ski it seemed the rear one might not be opening. I cleaned and inspected both. The rear valve I did first, with the intention of doing one at a time.Not being famaliar with what the should look like or the parts inside, I took the other one out to compare. Good thing, the first, didn't have an o-ring on valve shaft. Both bellows & retaining spring looked to be in good shape. Put them back together and tested ski on lake. Rear valve leaked immediately and when I pushed on them it didn't spring back like the other one. I now believe the bellow is no good. Have rebuild kit on order. Before the valve cleaning and changing to the correct spark plug the ski ran good. Only a slight hesitation at 3/4 throttle and when the gas dropped below 1/2 tank. Now it has hesitation at all throttle positions and doesn't have as much power. I have not replaced gray fuel lines yet. The fuel filter is clean and inspected a few lines and didn't see the gummy substance that they should have. the carbs might need some tuning but I don't feel it is the problem. Dont know if Im comfortable doing that myself. Do you think the rave valves are still causing the hesitation, if one of the bellows aren't functioning? and it was harder to start with the wrong plugs but ran much better. I think it runs a little better each time I take it out.

Thanks jm
 
My Goodness! what a great description of your work done.
Replace the fuel lines.ONE AT A TIME.No stuff-up then.Get the dig. camera out before you start and take a heap of shots.It costs nothing to do and may save heaps later.My lines seemed great but cost me a full rebuild.Read and listen to the guys on this site.Sometimes it gets a bit high tech,but ask for laymen/basic terms.This is only because they love and want to help others.They helped me.Your questions are great and all relate to the perfomance of the ski.
I would answer but there is a lot more people with a more exacting answer
All the best
 
Jam, Before you do any more work on the engine or carbs you really need to do what crisso said and replace the grey fuel lines. After that you will most likely need to rebuild the carbs.It is fairly straight forward just take your time and don't get in a hurry. Make sure you use a Mikuni rebuild kit not some after market cheap kit. The best suggestion I can tell you is to do one thing at a time and test. But right now the fuel lines need replacing. Hope this helps you.

Kyle
 
One thing on the RAVE valve is to be sure the bellows are connected on the main plate that you had to use the hex wrence to remove. I just cleaned mine yesterday and noticed that it was easier to connect the bellows to the plate in my hands BEFORE i put them back on the ski...

Just a thought!
 
Thank you all for your comments. I know the grey fuel lines need replacing but i also would like to play on ski this season too. I planned on doing them later, but everyone says Now. I will soon. In the meantime i was going to try to set the idle on the carb. It has a hard time idling after its started. Or it could be the throttle adjustment is off. Are the rave valves the same for all rotax engines? What about the bellows-r they interchangeable? Would a bad bellow allow valve to leak? now it seems to be leaking more since I cleaned it and put the missing o-ring on. P.S. I put the bellow on the main plate while out of the ski too. wasn't sur if that would be ok, but I knew it would be much easier to attach zip tie out of engine.
 
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Jam, Your low speed screws on your carbs should be 1- 1 1/4 turns out and your high speed screws on your carbs should be set to 0 turns out. Some have said, that know a lot about these things, that the MAG high speed screw is set to 0 while the PTO screw is set to 1/8 turns out. Either way I think you will be in pretty good shape. After do you verify these settings then you can adjust your idle screw which is located on the MAG carb on the side toward the front of the carb.

The bellow is the same size for all 787 engines. Make sure you attach the bellow securely to the plate and use the spring loop but you have to be careful not to stretch the spring too much. I suggest that you book mark the X4 thread on this forum and refer to what others have said. You start at the first and read through the posts. You will gain a world of info from that for sure. In addition, there are a great bunch of guys with many more years of experience than I have who work on these things all the time. Where in Cali do you mostly ride? Hope this helps.

Kyle
 
ok first thing is first, change those lines and clean anb rebuild those carb before you melt that new motor down! the grey fuel lines rot inside plug the inturnal carb filters and make the ski run lean, which makes it run hot and you could blow the motor. second, when installing the new rave valve gaskets, put a little bit of black gasket make on them, now when i say a little i mean very little, just a light coating.

you should start with changing the lines, cleaning the fuel selctor and clean/rebuiling your carbs, then we'll go from there.
 
what kind of oil are u running in the ski ive been told that cheap non-synthetic oil does that to the raves but im unsure.im switching to the mystic full synthetic thats available at academy for 20 bux a gallon.ive ran my skis empty so i can start with new oil but as im leaving for kuwait on fri i wont have a chance to test it.my priority now is winterizing
 
Thank you all for your comments. I know the grey fuel lines need replacing but i also would like to play on ski this season too. I planned on doing them later, but everyone says Now. I will soon. In the meantime i was going to try to set the idle on the carb. It has a hard time idling after its started. Or it could be the throttle adjustment is off. Are the rave valves the same for all rotax engines? What about the bellows-r they interchangeable? Would a bad bellow allow valve to leak? now it seems to be leaking more since I cleaned it and put the missing o-ring on. P.S. I put the bellow on the main plate while out of the ski too. wasn't sur if that would be ok, but I knew it would be much easier to attach zip tie out of engine.

if a RAVE is spitting oil right after you cleaned them take the black cap off and check something didn't come apart. Also, you have to be careful with zipties on the bellows, the little nub on the zip tie could wear a hole in the bellows. you have to use really narrow ties to fit in the groove and try to trim the sharp corners off the nub. you might be better in the long run to get replacement spring clamp to use instead of the zipties because that little piece of rubber is like $34.
 
1 year with a 2 week r&r after 6 months. Possibly longer if I decide to stay. Mostly goin to get a nice downpayment on a house tired of renting
 
Jam, Your low speed screws on your carbs should be 1- 1 1/4 turns out and your high speed screws on your carbs should be set to 0 turns out. Some have said, that know a lot about these things, that the MAG high speed screw is set to 0 while the PTO screw is set to 1/8 turns out. Either way I think you will be in pretty good shape. After do you verify these settings then you can adjust your idle screw which is located on the MAG carb on the side toward the front of the carb.

The bellow is the same size for all 787 engines. Make sure you attach the bellow securely to the plate and use the spring loop but you have to be careful not to stretch the spring too much. I suggest that you book mark the X4 thread on this forum and refer to what others have said. You start at the first and read through the posts. You will gain a world of info from that for sure. In addition, there are a great bunch of guys with many more years of experience than I have who work on these things all the time. Where in Cali do you mostly ride? Hope this helps.

Kyle

Thanks Kyle, I installed the new bellow with spring loop. Works much better. Tested the ski. It ran much better. And I will changed the fuel lines next. Will start working on that tomorrow.
 
I know-change the fuel lines now. I will start on that tomorrow. Installed the new bellow with spring and it doesn't leak. It ran much better today. When u say clean the fuel selector- is that the dial to turn fuel on/off/reserve? If so, earlier this year when I was exploring things that were possibly wrong with the ski. I read somewhere to switch to res and if it worked then my problem was something else. That sdoesnt matter. What happened when I switch to reserve-was the ski starting cutting out and ran worse. Now when my fuel is low reserve wont pick it up nor the main tank. It is like it is out of gas. Will cleaning the selector fix this? I will have to look up the how to clean selector switch. I read about it breifly somewhere. Didn't use black gasket make. but when I take them apart next time i will.
 
Runnign Non synthetic oil now. I will use syntheic. Can I add it to current oil. If not, how do I syphon the oil out?
 
I know-change the fuel lines now. I will start on that tomorrow. Installed the new bellow with spring and it doesn't leak. It ran much better today. When u say clean the fuel selector- is that the dial to turn fuel on/off/reserve? If so, earlier this year when I was exploring things that were possibly wrong with the ski. I read somewhere to switch to res and if it worked then my problem was something else. That sdoesnt matter. What happened when I switch to reserve-was the ski starting cutting out and ran worse. Now when my fuel is low reserve wont pick it up nor the main tank. It is like it is out of gas. Will cleaning the selector fix this? I will have to look up the how to clean selector switch. I read about it breifly somewhere. Didn't use black gasket make. but when I take them apart next time i will.

You can buy a new one from Parker Yamaha for this ski for $24... Well worth it if you ask me... http://www.parkeryamaha.com/seadoofuelvalve275500098.aspx
 
Runnign Non synthetic oil now. I will use syntheic. Can I add it to current oil. If not, how do I syphon the oil out?

i would drain the oil. you can disconnect one of large the gravity feed lines from the bottom of the engine and drain the tank into an empty bottle then some disconnect then blow thru the lne to force the oil out the bottom end, or use a shop vac to suck it out the hose. this way is pretty messy.

when I drained mine I bought this little oil pump from cabella's and just stuck the hose down each of the gravity fed lines, it's takes awhile but alot less messy. It's showing the price as $36 but I'm sure I only paid like $24. you can't let it run mvery long w/out oil pumping thru or it will burn up the motor.

http://www.cabelas.com/product/Seas...Ntt=oil+pump&WTz_l=Header;Search-All+Products
 
I know-change the fuel lines now. I will start on that tomorrow. Installed the new bellow with spring and it doesn't leak. It ran much better today. When u say clean the fuel selector- is that the dial to turn fuel on/off/reserve? If so, earlier this year when I was exploring things that were possibly wrong with the ski. I read somewhere to switch to res and if it worked then my problem was something else. That sdoesnt matter. What happened when I switch to reserve-was the ski starting cutting out and ran worse. Now when my fuel is low reserve wont pick it up nor the main tank. It is like it is out of gas. Will cleaning the selector fix this? I will have to look up the how to clean selector switch. I read about it breifly somewhere. Didn't use black gasket make. but when I take them apart next time i will.

Jam, When you change out the fuel lines you may want to take a few extra minutes while you're in there and check the filters on the crabs especially if the fuel lines are gunked up like I would suspect they are. It's a fairly easy process and I can step you through it if you don't know how. Without these little filters being clean your engine will be staved for fuel and will run like crap if it runs at all. Take care and good luck.

Kyle
 
My carbs were so full of crap, I had to take them to a friend and have them vatted before I could rebuild them... That Green goo is tough to get out of all the little nooks and crannies...

Where in AL Kyle? Bham here!
 
My carbs were so full of crap, I had to take them to a friend and have them vatted before I could rebuild them... That Green goo is tough to get out of all the little nooks and crannies...

Where in AL Kyle? Bham here!

Bham also pitguy3. I ride and boat up on Smith. Where do you ride?
 
Logan Martin... We live in Leeds so it's not that far... I will PM you the name and number of a GREAT ski mechanic if you want it... He's in Hayden..
 
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