720 Rave Cylinders

[falklandsx]

I have a lead on a set of 720 cylinders that are set up with rave valves. I haven't seen them yet, but i'm told that Rotax built them for the factory race team before the 787 was developed, and that they were used on the XP and HX.

Anyone out there know anything about running these? Worth picking up? If so, any idea in terms of value? We haven't talked price yet, but I've done business with the seller in the past and he is offering to throw them in as part of a larger deal... only problem is that I'm not sure if the larger deal is going to happen yet. In either case, I love rare race stuff and want to grab these if running them is still feasible.

Any input would be appreciated.

 

[Matt Braley]

Yes I have and know about these. The "upright rave" engines were race3d before the 787 came out as the guy said, however many earlier one were based on the 670 Rotax sled engines and may not fit the 720.

Rotax Racing would turn down the 670 case to accept the 720 front flywheel cover. These cases were stronger but the engines were winning so other racers complained because the skis were supposed to be based on a production model. After that they started putting the raves on 720 based engines. Many had longer rods and a spacer between the jugs and case(stroker) to bring the cc up to 785 without going over.

The problem I have with this super cool old stuff is that it was made too aggressive for everyday use. Racing fuel is required to run the upright rave engines I have so they sit on the shelf waiting for a race.

 

[falklandsx]

Thanks Matt, great information! Might you be able to share a photo or two of one of these motors?

On the 670 vs 720 point, what's the best way to tell what application these jugs are?

Disclaimer: I have zero experience with sleds, but I'll read up on the 670.

:cheers: