I have 1800 miles on my 02 MXZ 600 and for some reason I don't have near the power that I did the first year I bought it. Guys that I was beating a year ago are kicking my butt now. And it is not even close. I haven't checked the exhaust valves yet, but would 10-15% power loss be a symptom of sticking valves? I cleaned the valves at the beginning of this season. They weren't even really dirty, though they only had 500 miles on them. I did change to a new belt. Top end seems to be affected also. I put new plugs in. The sled is running fine, not sputtering or anything. Gas mileage seems to be normal. I use Amsoil synthetic for oil. Where should I start? Could my reeds be going bad?

Thanks for your help.

to see if your raves are working you drill a hole in your plastic rave caps. the directions where i will take you say to use a 7/8 inch hole, i think i used the biggest drillbit i could in my drill and it is a 3/8 inch hole i drilled.

anyways go to www.off-road.com (http://www.off-road.com) then click on the enter, then click on snowmobile on line, then on the left click on info and tech center, then last click on rave maintenance.

i forgot to say after you are finished lift the back of the sled and see if they are working once you have the caps put back on.

A major symptom is going to be loss of rpm. Is your sled still hitting the peak rpm that it is supposed to? Another place to look is your clutches: when was the last time you cleaned them and made sure your springs weren't pooched?clean the clutch faces?

We have an article on RAVE maintenance in out technical area for reference.

Don't forget the compression check.

RAVE's are so easy to clean you may want to do it a couple of times a year just to make sure you're running at peak performance. Sticking RAVE's will not effect your bottom end and will your fuel milage will not suffer greatly. However the top end tends to really drop. You should notice this on your tach and speedo. Since you have an 02 you already have the springs on the bellows so cleaning is a snap.

If you also changed the belt that might be the reason if it is an aftermarket belt.I've seen a loss in speed using an aftermarket belt and when switched back to an OEM belt the performance came back.

Just to reiterate what paul yarek said about drilling inspection holes in the RAVE caps -- DO IT!

It works really well, and you always know that the valves are working properly,and in synch.

since it is almost the end of the riding season you might want to chedk your reeds and make sure they are closing properly, not cracked or flaking. This will afect the performance of the sled also..just a thought.....
:)