I have a 1996 670 Summit that is bone stock with about 2,600 miles on it. The sled runs great, but at 3/4 to full throttle it begins to cut-out, especially when it is pulling hard in deep snow or on the hill. I've checked everything I know out, but thought that I'd ask the experts.

We were on the trail the other day and opened it up. It immediately jumped to about 8,000 RPM and took off, then started to back off as I held it wide open to about 6,000 RPM.

Here's where the motors at:

Compression: 153 both cylinders

Plugs: Like tan color like they should be, both same color

I was wondering if you guys thought that it would be clutch problems, and if it is, which clutch? I serviced the secondary apart and cleaned it last year, but have never had the primary apart. Although I keep them blown out with an air hose.

Any help would be appreciated!

Rave valves sticking??? have you ever cleaned them?

Rave valves sticking??? have you ever cleaned them?
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I cleaned them the beginning of last year, only 300 miles since cleaning. They move very easily in and out, so I don't think that that is the problem. Thanks for the advise though!

Sounds like my problem.

Click (http://www.snowmobileworld.com/forum/index.php?showtopic=60471)

I cleaned them the beginning of last year, only 300 miles since cleaning. They move very easily in and out, so I don't think that that is the problem. Thanks for the advise though!
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Check your spark plug caps, they may be burnt up inside causing a high RPM miss fire. As said before check or replace your primary spring it may be sacked out.

You're hitting 8000 but it drops off under load? Sounds like a clutch problem. Time to check the primary

Check your spark plug caps, they may be burnt up inside causing a high RPM miss fire. As said before check or replace your primary spring it may be sacked out.
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I just replaced the spark plug caps, one was a little loose, so hopefully that will do the trick. Thanks for the help and if it does it again I'll look into the primary.

Have fun Riding!

I was having a similar intermittent problem has year. Could not figure out if it was fuel or electrical. The stator finally died.