1150 Dyna coil going bad?

[Carter Turk]

Hello,

I suspect my coil for number !&4 might be malfunctioning. Plugs are sooty dry black on those cylinders. I pulled the carbs off to check for blockage of the idle/pilot/circuit.

They've run well for 5 years with a minor hiccup at the pilot/needle overlap.

The fouling seems to occur during steady minute throttle openings less than 1/8 and just started occuring with a larger baffle pipe that I put on while waiting for the new smaller diameter one to arrive, which may or may not have any relation to the problem.

I went on an 800 mile road trip in September with the same set up minus the larger baffle with no issues.

I ride every 3-4 days rain or shine through the winter.

Any tips to help physically inspect/troubleshoot the problem? I have an analog multimeter, but don't know how to use it or what settings to test with. Would the stator failing cause these symptoms at low throtle openings? Its original so it may be on its way out.

Bike is a 1983 Katana 1100 with 84 1150/1229 motor, stock 1100 electrics with the exception of the Dyna coils (green) 90 GSXR 36mm slingshots with dyno jet kit needles forth clip down from top 147.5 mains, 32 pilots, Airfuel 2 turns out floats leaned out to 17-18mm? K&N pods. Kerker 4/1 K series with aluminum can.

Clueless in the N.W. Thanks for any help.

[SqDancerLynn1]

Easiest way would be to swap the coils & see if the problem follows the coil

[skip]

when the dyna coil went bad on my 1150 the bike ran well then it would drop 2 and 3 after it had been running for a while. If I let the coil cool the bike would run again. Each time it took less time for the coil to heat up and drop the cylinders till finally it was not drivable.. Like was previously stated, swap the coils and see if the problem follows to the new cylinders.

[Carter Turk]

Thanks for the tips SQlynn and Skip.

What about the spark plug wires being different lengths. Should I pull those out of the coil and switch too?

I don't think the wires on 2-3 coil are long enough.

[jeff.saunders]

Your problem could be coils or wires or ignition or your pipe (and the impact to the carburation). If it were carburation problems, normally it would hit all 4 cylinders the same - so it's unlikely to be this, although it can be a contributing factor.

Swap the coils, but leave the wires on the current cylinders. Then if that produces the same result, swap wires to see if the problem follows the wires.

Coils do go bad, it's best to check the primary and secondary resistance of each one - you should see a nominal 3.0 on the primary side (usually a little over) - measure on the teminals going into the coils, and over 14k on the secondary side - measure with the plug wires removed.

You could have a back pickup on the ignition - swapping the coils from side-t-side may point to this if the problem does not follow the coil or the wires.

If you need a single coil, we can help you - we do sell individual ones.