Hello Everyone,
I just bought this 2005 Viper 90 for my daughter and its lacking in power. It starts up right away and it idles good. The quad has no power, it barely takes off. My cousin has a 2003 50 and it smokes this 90 like nothing . The engine is also lacking that good ole 2 stroke wind up. What do I need to check first? The carb was just cleaned and it did not make much diff. Any advice will help.
I've read some post and people are writing about changing clutches or adjusting them but I thought thesequads were/are automatics
I am very new to this, to both posting and the mini ATV's so this will be a learning experience.
Thanks

 

Did this happen all of a sudden or came about gradually?..A good place to start is check the compression..Ours was 125psi when it was new..Anything under 90 PSI it will probably start to feel pretty lazy....If that checks out clean out the carb and check the jets to make sure they are not clogged..Make sure the fuel is flowing good from the line and the filter is not clogged...Is the spark plug in good shape and air filter clean?...If all of that checks out check the rollers in the variator..Sometimes they get worn flat and won't shift properly....

These quads are "automatics" but there is still alot of mods you can do to the clutching..You can adjust how high you want the engine to rev before the clutch engages and also change how quickly you want it to shift...

 

Thanks Oldyeller,
I will do that, first I need to buy a comp. tester. I actually just bought this about three weeks ago. the first thing I did was change the plug and air filter. A friend cleaned the carb and it ran just a bit better but not much. Are these fixes easy to do? Is there a service manual available that will guide me with the fixes?

 

Pull the silencer off it and try running it with the rear wheels off the ground, see if it wakes up. If so then check the exhaust spark arrestor, the 2-strokes are noted for getting gummed up and plugging, hence restricting exhaust flow and restricting RPM's...

Get it to rev on a stand first before monkeying with clutches, etc. If the engine isn't making power, all the tweaking in the world of the drivetrain won't help.


Keep us posted

.

 

Also I think the 2005 had an adjustable CDI and you will need to make sure it is turned all the way up.

 

Oliver 550
yes I tried the CDI and its at 7 now, but that did not make much diff. Do you have any other suggestions?
Thanks
Im really new to this posting, and i dont know if you get notified when I respond to yor answers .

 

Did you try checking the exhaust like I suggested? What did you find?

 

Excellent point...The later model etons had some problems with clogging spark arrestors...