Is there anyway to test cdi unit on yamaha 540 vmax snowmobile

Unscrew it from the back of the speedometer and follow it back to where the cable terminates at the hub of the track. Undo it there and replace it with the new one.

https://www.google.com/search?q=1996+Yamaha+Vmax+XT+600+snowmobile.+How+can+I+replace+speedometer+cable

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Should be normally open and shorts plug to ground when you fall off.

First you need to determine whether the fault is caused by poor engine performance or whether it is being held back by excessive friction in the driveline.

Does It Have A Vacuum Modulator On It For Shifting Gears? If So, Have It Checked Out

if it is backfirering sound like timing is out of spects

YOU HAVE TOO MUCH FUEL GETTING INTO THE ENGINE,USUALLY CAUSED BY A FLOAT SETTING ISSUE IN THE CARB

Which bulbs are the ones burning out? They may have a short on a common wire that causes them to burn out. You should probably also check the stator to make sure it is not shorted out or producing higher voltage than it should. This can also cause bulbs, batteries, and regulator/rectifiers to burn out.

it could also be the neutral light wire

sounds like the belt is wrong size. double check this,and if it is correct size make sure the secondary clutch is closing all the way.