SXR Single pulse line duel carbs

[naithgroves]

Im having a problem with the front cylinder being slightly leaner that the rear. The ski also sometimes backfires on start up and once warm intermittently it will break down into running on one cylinder at WOT. I have duel BJ 48s and have tee'd them into the pulse line on the front cylinder. Could this be causing the lean condition in the front cylinder? The only other things I can think of are it being the crank sensor, bad wiring or the Advent t3 Ignition....

 

[tor*p*do]

More info needed.
What motor setup

 

[naithgroves]

Its a Kommander Australia built duel cooled freestyle ported sxr motor bored to 840cc, R and D head 190 psi, advent ignition, total loss TBM fly, standard reeds, R and D intake, Twin Blackjack 48s, NYNJA pipe and a modded SJ waterbox

 

[naithgroves]

Forgot to add it has a stock 13/18 sxr prop in a solas 140 12 vein

 

[Big Kahuna]

2 Carbs = 2 pulse lines
2 Carbs + 1 Pulse Line equals bad running ski.

Get an external fuel pump and the pump block off plates or tap your cases for a second pulse figure.

 

[naithgroves]

After re wiring the electrics, new
Crank sensor and drilling another pulse line I found this. Haven't put it in the water yet but I'm assuming it was the problem! It's the earth wire, basically crumbled and broke off.

 

[MADMAT]

After re wiring the electrics, new
Crank sensor and drilling another pulse line I found this. Haven't put it in the water yet but I'm assuming it was the problem! It's the earth wire, basically crumbled and broke off.

View attachment 230176

Seen that more than a few times!!!

 

[naithgroves]

Well turns out that wasn't the problem..... Ive got very weak spark if any in the front cylinder. So basically it only runs on one cylinder. Have changed the crank/flywheel sensor, coil and it still does it.

Im thinking it might have something to do with the signal from one of the magnets on my TBM flywheel? I don't use an oring on the front cover (Just use the R and D spacer gasket they supply with the timing advance). So this spaces the cover out slightly. Would this be far enough to cause weak signal and for one of the cylinders to fire only partially? It does spark but it's very weak looking and is inside the plug and not onto the electrode.

Is this something An Advent T3 can do? Or can the magents on the Tbm flywheel become weak over time and create this problem

 

[IceRocket1286]

Advent CDI's are not the best. They work when they want, cut out at random, and are generally a hassle. Throw in your Stock cdi and see what happens, then go from there. I would be surprised if this does NOT solve your problem.

Well turns out that wasn't the problem..... Ive got very weak spark if any in the front cylinder. So basically it only runs on one cylinder. Have changed the crank/flywheel sensor, coil and it still does it.

Im thinking it might have something to do with the signal from one of the magnets on my TBM flywheel? I don't use an oring on the front cover (Just use the R and D spacer gasket they supply with the timing advance). So this spaces the cover out slightly. Would this be far enough to cause weak signal and for one of the cylinders to fire only partially? It does spark but it's very weak looking and is inside the plug and not onto the electrode.

Is this something An Advent T3 can do? Or can the magents on the Tbm flywheel become weak over time and create this problem

 

[High Speed Industries]

I had the same exact problem on my kawasaki 750. It turned out to be a bad stator.