Stock Viper Top End Problem

S

SeX Viper

Member
Joined
Feb 11, 2011
Messages
57
Age
41
Location
Minneapolis, MN
I have an 02 stock Viper with about 8000 miles on it. Just had a great weekend riding in the UP but have a little issue that I can't seem to resolve. When you hold it wide open it shoots right up to 95 with no problems running around 8600 RPM but then over the coarse of anywhere from a 1/4 mile to a mile it slowly starts to loose rpm down to about 7000 and only run 70 mph. If you back off to under 50 mph and pin it it will shoot right back up to 95 and start all over again. I put a new belt on but that didn't help. Carbs are clean and power valves are clean and adjusted. I am kind of at a lose, thinking maybe clutches need to be rebuilt or the PV servo isn't holding the valves open. I was also getting worse gas mileage than usual. I just rebuilt the rear skid, chaincase, drive shaft, and jackshaft bearings and I don't see any drag issues as I can spin the track by hand with similar resistance to what it has always been.

Thanks for the help, this web site has saved me a ton of time and money as I have always been able to fix my sled with all of your help.
 
ok, I know tony was thinking the same thing as me the clutch springs are probally whooped/worn out with 8000 miles on them. Likely a good idea to take both clutchs apart and go thru them, might need a few parts replaced.
 
I will start there then. Is there a thread on rebuilding them? I am a fairly capable mechanic just need a little push in the right direction. I think Yamaha has a rebuild kit or do you guys suggest going after market? Also, do I need any special tools?
 
So I finally got around to replacing my springs today, the joys of having a new born. On the primary the rollers and weights move free and do not have any flat spots. You can feel some play in the clutch faces once the spring is removed though, should there be any? If not I will order up a new set of bushings. Thanks.

Also, this may have played a roll in my initial issue but I also replaced all of my reed pedals. A lot of them were chipped and one was even broken off. I will be riding it this weekend and will update how it runs. I have to imagine I will notice the affects of the new reeds and this must have contributed to my poor gas milage.
 
I have same issue as yours but my RPMS drop after a couple of feet. What do your plugs look like after it falls back to 7000 RPM? Do a plug chop when it happens and post pics. I found cylinder #1 not firing properly which takes drivetrain out of the question.
 
SeX Viper said:
So I finally got around to replacing my springs today, the joys of having a new born. On the primary the rollers and weights move free and do not have any flat spots. You can feel some play in the clutch faces once the spring is removed though, should there be any? If not I will order up a new set of bushings. Thanks.

Also, this may have played a roll in my initial issue but I also replaced all of my reed pedals. A lot of them were chipped and one was even broken off. I will be riding it this weekend and will update how it runs. I have to imagine I will notice the affects of the new reeds and this must have contributed to my poor gas milage.
Click to expand...


My reeds were shot at 6500 miles. I think the summer gas treatment I use may have played a roll in making them weak.
 
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