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RapKor
08-10-2010, 10:48 AM
Hey guys got an 05 90 viper for my daughter, she has gotten pretty comfortable with it so I have started to tune on it. It now has a stock apex pipe on it with the stock carb which I believe is the 18 sudco and the oil injection removed. I have started to play with the jetting (stock was an 85 main unsure of pilot) jumped up to a 102 main and thing ran better but was a bit loggie in the middle and top, seemed to run ok on the bottom and top but really struggled to pull RPM's on the way to the top. Idled fine but took a long time to get to the top! went back to a 95 main and bike seemed better all around but still labored to rev thru the middle. I should note that the clutching is stock as well as the air box/filter.
Anyone have any suggestions on where to start with these mods? I plan on running a UNI on the stock carb and was hoping that someone could tell me the part number to run on this carb.
I know clutching will need to be tuned as well but I want to get the motor running well before I tackle that! Thanks any input is appreciated!!
nastynotchback1
08-10-2010, 12:49 PM
The problem is the clutch more than likely.The clutch being out of wack will act as if it's a carb problem when in-fact it's a clutch issue.I know for a fact that the stock clutch tune will not work with a stock apex pipe.been there done that.
RapKor
08-10-2010, 05:54 PM
Any suggestions on where to go with the jetting?

I am sure the clutching will need to be re-done, will take any advice you can give on that as well, was thinking of 4 g rollers 1500 rpm ztr spring and red malossi clutch springs.
I am afraid the bike will run to lean and burn down so I was hoping to get a good safe starting point for the jetting then do the clutch work. Again I would appreciate any help you can give. Thanks
nastynotchback1
08-11-2010, 06:02 AM
Install a new plug and run it out and check the plug.With a koso pipe and unifilter on a stock motor(70cc) i ran a 115 main.

as far as clutch goes i prefer the ztr springs.I think 4.5 roller/1500 torque spring/2000 shoe springs may be a good start although someone may have a better suggestion than this for you.