What's the trick to remove the MAG RAVE valve?

[jimmaki]

According to the shop manual on the 787 engine in a 1998 SPX, to remove the RAVE valves, just remove the top plastic cover then loosen the two allen screws and pull the RAVE valve out. That works fine on the PTO RAVE, but on the MAG RAVE, the top of the assembly hits the exhaust pipe before the paddle clears the hole it's in. I didn't find anything in the shop manual about how to get around this snag. I think it assumes the engine is out of the ski? Tell me is isn't so. Can I take the RAVE assembly apart, i.e., unscrew the piston from the paddle and remove the bellows. My fear is the paddle will fall down into the cylinder or I'll damage the paddle or exhaust port torqueing off the piston retaining nut. Is there a simple trick? This is an annual suggested maintenance so I'm hoping it doesn't involve taking the exhaust pipe off or something like that.

PS: The PTO RAVE is not that bad but there is some encrusted carbon on it on the top side so tempted as I am to just button up the MAG RAVE and pretend I didn't try to get it out, I probably need to clean it or have problems down the road.

 

[WhiskeyD]

Just unscrew the cap/bellow and it will all slide right out. The rave wont fall into the engine or anything like you are worried about.

 

[MPower]

You have to completely disassemble the MAG side RAVE so it clears the exhaust. Leave the housing bolted down until its just the valve left. PTO side just unscrew the housing and pull the whole enchilada out.

 

[jimmaki]

Thanks, I was hoping that was the answer. I looked at the PTO RAVE which I had completely out as an assembly and finally realized the nut on the paddle stem was part of that plastic shell which pretty much unscrews just with finger pressure. Removing the bellows retaining spring and bellows wasn't as hard as it looked.

Glad I took those suckers out because they look like they need cleaning to me (even though they move up and down freely) .... although this is the first time they have been out in 18 years running on XPS mineral so not as bad as it could have been. In 18 years I think I've only run 2 or 3 gallons of oil though the machine so it's pretty cherry if you don't count what 18 years of sitting out in the Florida sun can do.





What do you recommend I clean the gunk off with? Chemical clean with carb cleaner or mechanical removal with wire brush? Has anyone used a spray on oven cleaner like EasyOff? I use it on my BBQ grills and it gets even the burned on carbon off easily.

 

[jimmaki]

Yea, I was looking at the PTO RAVE which I had all the way out as an assembly and did finally notice that round boss that stops the paddle from falling into the cylinder. Thanks for your help! It's out.

 

[MPower]

Those don't look bad at all. You wouldn't believe some of the ones I have seen.

But still a good idea to clean them. I use a bench grinder with wire wheel. Super fast and they come out looking brand new.

 

[Sportster-2001-951C-Stock]

The RAVES of my 951 were stuck pretty good when I got it, took a while to free them up and had to clean them again within a couple weeks, it was filled with the wrong, outboard oil. So far it seems like I need to clean twice/season and I consider my usage light, maybe it takes awhile to get the heavy carbon out of there....

I also last time, left a few squirts of 2-stroke XPS2 inside the bellows to hopefully provide some extra lube for the shaft bore, not sure if it really helps but made me feel better.....

 

[WhiskeyD]

You don't have to take the bellows off the caps unless you just wanted to, sorry didn't make that clear. Looks like you have the newer slotted style raves, I need to upgrade mine sometime .

 

[jimmaki]

Those don't look bad at all. You wouldn't believe some of the ones I have seen.

But still a good idea to clean them. I use a bench grinder with wire wheel. Super fast and they come out looking brand new.

That's probably the way I'll end up cleaning them, but it would be even easier to douse them with EasyOff and wait an hour or so and rinse them off. That's assuming they're made out of stainless steel or at least not aluminum. They feel too heavy to be aluminum. My only concern keeping me from starting with your suggestion is that the wire wheel on my grinder is steel bristles. Since I don't know what the paddle is made out of, I'm concerned the wheel could remove more than carbon, especially around the track grooves and the angled sharp edge where most of the carbon is.

 

[jimmaki]

The RAVES of my 951 were stuck pretty good when I got it, took a while to free them up and had to clean them again within a couple weeks, it was filled with the wrong, outboard oil. So far it seems like I need to clean twice/season and I consider my usage light, maybe it takes awhile to get the heavy carbon out of there....

I also last time, left a few squirts of 2-stroke XPS2 inside the bellows to hopefully provide some extra lube for the shaft bore, not sure if it really helps but made me feel better.....

You bring up a good point ... it seems a little self defeating to stick a nice squeaky clean RAVE paddle down into a black dirty oily hole which who knows how much crap in it. But I don't want to clean the hole send all that crap down into the ring lands.

 

[jimmaki]

By slotted style do you mean those two grooves that look like tracks? The old ones were just flat on both sides? As close as the RAVE paddles can come to the piston some kind of indexing would seem like a very good idea so they don't get cocked at an angle letting one side down deeper into the cylinder.

 

[WhiskeyD]

By slotted style do you mean those two grooves that look like tracks?

Yup. The original flat ones were prone to breaking I've heard. I cant remember the number stamped on them but I checked mine last season and I definitely have them :ack: