Super Jet New motor running on one cylinder! Need help?

BIGRED Z

BIGRED Z

Location
COMMERCE TWP, MI
I just started my new build for the first time yesterday. It started up but sounded off. I ran if for a little bit on the hose and found one cylinder warm and the other ice cold. Poped the plugs and one cylinder is not detonating. Cylinder is getting fuel as it is ending up in the pipe chamber. I checked compression and I have 180 in each hole. I also. He k spark on both plugs and no trouble there ( bright and blue). I thought it might be a timing issue so I pulled the front cover and checked the key and stator timing mark and both are in the correct positions. I'm kinda at a loss of where to look next? Any help would be great


Background on the ski: 771 big bore ( nicely ported) built by #zero. Vf2 reeds, Ada head with 35cc domes, factory pipe with mod chamber, fresh built sbn 44's with a reed spacer, a/m flame arresters, 61x electronics, msd enhancer and msd coil.
 
DAG

DAG

Yes, my balls tickled from that landing
Location
Charlotte, NC
Compression / Fuel / Ignition

Do you have a primer? Will it run if you manually put fuel down each carb
 
Last edited:
Tyler Zane

Tyler Zane

Open Your Eyes
Location
Panama City Beach, FL
I had a similar issue last year, both cylinders had spark, fuel and compression... so i thought. Ended up messing with it a bit later that night and when i turned it over one plug looked like a Christmas tree. It was traveling around the boot and straight to the head. Cut my wires back a tad and started using dielectric grease where the wire meets boot and boot meets the plug. Added a thick zip tie to both ends of the boots as well and i have not had a problem since.
 
BIGRED Z

BIGRED Z

Location
COMMERCE TWP, MI
I'll check the wires. It's a new msd coil but I'll check. Just pulled the flywheel and all is well in the front. I also pulled the intake to double check the reeds and none are broken although there is a lot of fuel down there. Everything I know is telling me it's electrical. Any other thoughts let me know. If push come to shove I have the same ebox in my blaster that I will swap over. I know for sure that set up is good as I've ridden that ski a few times this year already.
 
ScottS

ScottS

X
Site Supporter
Location
Savannah, GA
BIGRED Z said:
I had just put 2.3 n/s in the carbs to lower the pop for the aftermarket f/a. I plan I pulling the. Arbs back apart to take a look again and double check the pop.
Click to expand...

I have seen a needle-in-seat stick once and it made the motor act just as you describe, but more than likely your linkage between the carbs have slipped. Pull your flame arrestors and look down the carbs and make sure both butterflies are moving together. Do it while the motor is running as the vacuum will hold one closed if it has slipped.
 
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