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914World.com _ 914World Garage _ Weak spark with Mallory CDI

Posted by: Mueller May 27 2005, 12:14 AM

anyone else run into this?

got to find all my manuals to figure out if I should be running wires with X amount of resistance or special spark plugs.....

Posted by: lapuwali May 27 2005, 12:17 AM

Tried it w/o the CDI? You using the Link to fire it? Can it fire the coil w/o it?

Posted by: Mueller May 27 2005, 12:24 AM

QUOTE (lapuwali @ May 26 2005, 11:17 PM)
Tried it w/o the CDI? You using the Link to fire it? Can it fire the coil w/o it?

spark appears to be the same with the Link as without it....of course this was just testing with plug out and sitting on top of a ground......very, very weak spark...removed plug, huge spark (which I expected due to less resistance)

I have not tested the spark from the coil without the CDI. that'll have to wait till Sat.

Posted by: Dr. Roger May 27 2005, 12:55 AM

CDI's on a bike can break down in the windings causing an internal short. It usually starts out be getting a weaker and weaker spark.

they're usually very durable.

i'd try to find someone and borrow their coils to find out quickly if yours are bad. or not.

i'm not usually a parts changer but it's sometimes difficult to test these coils due to the amount of voltage going thru them and getting a real ohm-age weather their good or not.

how do you know it's a weak spark under compression? do you have a scope?

Posted by: Mueller May 27 2005, 11:06 AM

Roger,

CDI and coil are brand new, never used units......I have not pulled the plugs yet, they might be fouled or something, I do know that I was getting plenty of fuel when cranking the engine but just no firing of the plugs...my timing could be way off still, I figured I should get at least a "pop"

time to hook up a remote start button, the wife is not happy being the ignition grunt

I do have another brand new coil that I can try out and I'll test the spark without the CDI control........