Super Jet 701 One Cylinder Spark???

kx454

kx454

Location
Sweet Valley, pa
Got a 93 VXR that had a waterbox explosion.

Replaced:
New Crank Seals
New CDI
New Stator
New Coil
Carb Rebuilt
New Plugs
Reeds Look Perfect

Has basically a brand new electrical system minus the flywheel. How in the world can it consistently be sparking one cylinder? The problem follows the three coils I have (one of which is brand new). Is it possible that the flywheel is bad? The plug wires were cut back and all the wiring is perfect connections. It is driving me crazy. Am I wrong in saying that both plugs fire at the same time?
 
MADMAT

MADMAT

Location
Ohio
Swap plug caps and see if the other cylinder becomes the one not firing.

Yamahas don't care which wire goes to which plug if you simply switch them and the other cylinder becomes the issue then you know your wire is bad no matter how far you cut it back.

Unless you mean you have tried a brand new coil WITH brand new wires???
 
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Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
The older style Yamaha ignitions (which this 93 has) fires both plugs at the same time, every 180 degrees.
You seem to have ruled out the coil as the problem. The stator is fine if it sparks on one side.
Change out the CDI and see what happens.
 
kx454

kx454

Location
Sweet Valley, pa
We have tried two CDI's plus the brand new one installed...just tried a sea doo coil we had laying around and both cylinders fire. Apparently we have 3 bad coils on our hands.
 
kx454

kx454

Location
Sweet Valley, pa
Put it back together and it started and ran like a champ. Shut it down and it would not fire again....ruined another coil.....could it have a bad voltage regulator?
 
yurkanip

yurkanip

Location
Great Pacific Northwest
Damn, sorry man. You said it ran, like a champ then stopped? I had a new motor run perfectly!, then drop to only one cylinder but made absolutely no noises to make me think something broke internally (ie, crank, rod, etc etc). Turns out the electrical was fine and firing on both cylinders but my rear cylinder reed cage came completely unscrewed it was simply sitting touching the crank and did ZERO DAMAGE but the motor ran, it just would not run on that cylinder even though the spark plug WAS firing in that cylinder. By switching the wires and the same cylinder won't run.....it is entirely possible after your rebuild yours did the exact same thing mine did and you have a reed broken or reedcage came unscrewed from the reed plate due to an unclean loctite application.
Food for thought, and good luck.
 
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