no spark

[Chewy]

little background on my 80 interstate. bought it last year for cheap as it needed the starter clutch replaced. got that done and put almost 4000 miles on it in 3 months. the original engine had 108,000 miles and started looking at replacement engines due to the mileage, and a few oil leaks. went and looked at a 1981 interstate with 37,000 miles, service records to match. it started, but ran tough unless i was in the throttle half way, then smoothed out at about 2,200rpm. bought the bike for $250, brought it home. over the winter, i had pistol pete rebuild both carb sets, as i plan to use the old engine to maybe build a go-cart with. bike has been my shed the whole time while pulling the old engine out, and putting the new one in. now, i have no spark on any cylinder, with new plugs gapped .026, range according to my clymer manual is .024-.028

with a float charger hooked up, my numbers are as follows,

13.7v at the b/w wire for the coil, engine not cranking.
goes down to 9.71v when i turn the engine over.
pulse generator has 572ohm on one set, 0 on the other set.
kill switch is doing its job, only have power when it is set to on.

things i have done to fix the issue,

checked and cleaned electrical connections
checked and cleaned ground cable, and matching surfaces

i dont know where to go from here, and am asking for yal'ls help.

[Wilcoy02]

Have the battery tested under load at auto zone or a place like that. Sounds like the battery does not have enough power to turn your engine over.

[Chewy]

i have kept the battery on a float charger all winter. i pulled the battery, and placed it on my bench in the shed while i had the engine out. the engine turns over good, so i dont think the battery is the problem. i will pull it, and take it to oriellys today. up in this area, i wouldnt take an rc car to autozone for testing, the oldest person working there is 20 and didnt know what a crescent wrench was.

on a side note for the battery, i hooked up jumper cables from my explorer. i have a 1000 amp battery on it, and it made no difference in cranking speed or spark.

[Chewy]

what are the ohm resistance numbers for testing the cdi boxes?

[julimike54]

Have battery load tested, you don't have enough juice to spark at 9.* volts. Need about 11.5volts

[Chewy]

Have battery load tested, you don't have enough juice to spark at 9.* volts. Need about 11.5volts

went to oriellys and had the battery tested. it tested good, but needed to be charged the slightest amount. took 11 minutes to top off, including setup and removal from the charge station.

got back home, installed the battery, still no spark.

i still have good resistance on one set of the pulse generator wires, nothing on the other set. the readings didnt change as the engine was turned over.

could the pg have gone bad between when i had it running 3 1/2 weeks ago, to when i installed the engine 2 weeks ago?


please keep in mind that the engine currently in my 1980 frame, came out of a 1981. i dont think that matters, but am not sure.

[Chewy]

turned out to be the pulse generator.
i swapped it out, and the bike fired right up.

on to my next project for the bike: hydraulic clutch

link for this thread is here

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