Brand new guy looking for advice

[wmshay6]

Going to look at a 96XP this weekend. In doing some homework, seems to be a pretty well regarded PWC, might be a bit wild for a novice like me, but whatever . . . . Owner says it's "not getting fuel" so doesn't run. I've looked at a lot of Yamaha skis, but not really any Seadoo's. What are the RAVE valves people are talking about? What else might I look for on a 96 XP? I'll be taking my compression tester first and foremost, but what else? Is the standard 120-150 PSI Compression applicable here?

I've focused mostly on Yamaha since I'm familiar with their dirt bike, atv stuff. But open to other types as well.

 

[benjilafouine]

no run = no value. Buy it for the price of the trailer.

 

[mikidymac]

Correct oil, if it's blue or green it's wrong.
Does it have spark?
Perfect compression is 150 at 120 it's time for a rebuild.

At most a non running ski is $500.

 

[jts32]

When looking at a non running ski I always remove the plugs and PTO cover and turn it over by hand to see if everything feels smooth. Then a compression test, and check for spark.

If the compression and spark are good, and it is truly a fuel issue, a little premix should pop it off for a few seconds. I usually bring some premix with, but feel out the owner before trying to pop it off with a little down the plug holes. Have dealt with owners that want more $ because they heard it run.

 

[AKnarrowback]

Not running is not running even if the pre-mix kicks it over. If they want to charge more after they hear it fire then tell them to go get it fixed before you put anymore than the first asking price down on the barrel head.

So many things to consider on a non runner. Even if it fires on premix down a plug hole that is not proof it is going to work well on the water under a real load.

Non running is not valuable. As it sits it is only spare parts and has little value unless it is in clean condition.

 

[AKnarrowback]

Rave valves are exhaust valves.

History - The idea has been around for a long time but really came to be in the two stroke toy market on the 1989 skidoo mach 1 583. It made it's way into the seadoo line with the 787 motor, anyone correct me, with the 96 XP 800.

It stands for Rotax Automatic Variable Exhaust. It is a simple system working off of exhaust pressure into a bellows that expands and pulls a guillotine type slide into and out of the exhaust port based on exhaust pressure and engine rpm. It gives you a lower exhaust port at lower rpm's and a higher exhaust port at higher rpm's. The power curves of the two motors are different and the rave valve operates where the two curves "cross" giving you more torque at lower rpm's and more power at higher rpm's. The idea was how can they get a higher powered motor to produce good low end torque and the rave valve was one answer that was trouble free and simple in design. It gives you the "best of both both worlds" with low port torque and high port power, although "port" in this instance is a generic term.

It works because skidoo offered multiple "types" of the 580 motor in snowmobiles, with and without the rave. The non rave had good low end power but did not rev higher and was not as powerful as the rave type. The rave type pulled hard down low and transformed into a higher reving, higher hp motor on the top end. I never liked the non rave 580, too mellow.

It originated in moyorcycle racing, transformed to sleds and now most of the major sled manufacturers use some form of exhaust valve on their performance motors. Skidoo has used the rave, in bellows and computer controlled versions, since it was introduced in 89. Matched with the rotary valve it made rotax the best motor in the 80's and early 90's for sleds while everyone else was relying on "peaky" motors to make good power at the cost of them being finicky to tune for temp and altittude.

We used to mess with a guy in the shop and block one of his raves shut by cramming paper towels under the cap on one cylinder. He would cuss and fight trying to figure out why his motor wasn't running right.