Viper S backfires, kicks back.....

kielbasa

New member
Joined
Mar 14, 2017
Messages
21
Location
Kewaskum, Wi
Hi guys, all of a sudden i lost a cylinder or two while driving, mainly runs on one, with a second kicking in and out, backfiring out the exhaust and intake.
I installed new plugs, same thing......except now i can't even get it started, bangs out the exhaust and pulls the cord right out of my hands when it kicks back.
Stator took a dump? Anyone else experience such issues?
 

the pickup is tight and in place...........tried starting it again, the thing just tears the recoil out of my hands....hmmm.......
 
naw, it pulls over fine for a couple pulls, then once it fires it backfires out the exhaust and kicks back, runs for a half a second, dies, try pulling, pops and farts, tears rope out of hands.....
 
Maybe check the key for the flywheel and see if it sheared the key somehow. Crank out of phase? Sounds like a timing issue.
 
Needle and seat leaking, causing fuel to build up in the engine and back firing out the pipe?
 
when you had the recoil off, was the recoil cup that's mounted on the flywheel in good shape? I ask because I have seen the flywheel nut come loose before and the flywheel dances on crank end, the recoil basicly holds it on, its possible the flywheel has spun the keyway. if that's all good, then try another cdi box as that's the only other thing with timing it could be.
 
ya, the cup, coil, mounting bracket, etc look fine....there is a slight amount of surface rust on the flywheel (coil trigger surface), but i'd be surprised that's the cause....the flywheel is tight when grabbing with my hand.....
I also did a quick and dirty check of the crankshaft phasing, with results showing tdc 120 degrees apart using eyeball through the exhaust and a degree wheel, i'll use a dial indicator to verify, but nothing obviously out of whack....when cranks go out of phase, I assume it's likely to be 10 or more degrees????
I have NOT checked flywheel key yet though.......
 


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