Kawi2strokes.com Forum

Today, I rode to work on my newest '72 and the ride was rough. The bucking was terrible. I figured it was the product of my carburetor tuning, however, about a mile away from home,a new symptom arose: BACKFIRING! Upon inspection I found that my center cylinder only had a spark every now and then. I waited for the engine to cool, as well as the coils and restarted it. It ran well again for a minute or two then the center cylinder sputtered on and off. (I also tested it with a spark tester.) The other two coils are new, from Jessbikes, but the center is 1972. I've seen coils cut out when they are hot, but not cut in and out like this...that leads me to think control boxes? I'm going to replace the center coil and if that aint it, then is it the middle control box for the middle cylinder? Thankfuly I have spares. I also took off the rotor cover to inspect the pickups and found nothing suspicious. The good news? I may have found my "flat spot!" Any tips or prayers would be appreciated!

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1972 H2, modified and Tracy bodied. 77 Kawi 1000. Lime green. Cafe. Lester wheels.

40 year old electronics, not good.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

That would be a good poll question.
I bet 90% of the triple owners are still running the original coils.
When I changed to a John02R6 box my 72 boxes were working perfectly.

Pretty amazing that cheap electronics from the 70's are still getting the job done in this disposable world.

Zero, I think your trouble shooting is spot on.
If you have both spares, I'd go the coil first and control box second.
I can't see a carb that was running OK suddenly go to backfire mode and then work properly after cooling.
Suppose it could also be an electrical connection that gets hot and causes trouble.

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

All three of my original '72 H2 CDI units quit in 1979, one at a time. At least two more original CDI units failed a few years ago. A friend had a '73 H2, and I remember him buying at least one replacement CDI unit at the dealer back in the late '70s for $50, which works out to a couple hundred with today's dollars. I have an H1D set I got from eBay before I started making them, and the CDI units are OK, but the rectifier has a bad diode. I don't mean to sound self-serving, but I wouldn't use original ignition units without carrying spares. Some of mine that failed became intermittent toward the end, driving me nuts trying to find the problem.

When I took the bike out of the van after the 2011 Deal's Gap meet, it ran on two cylinders. An original coil had failed, apparently while I drove it up the ramp into the van to come home, or in my driveway as I was starting it.

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If it surges, that's normal, upshift.

Swap coils with with either right or left and see if the issue transfers to the other cylinder.

Right. You can just swap the wires without actually moving the coils. Same with the CDI units.

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If it surges, that's normal, upshift.

Who is the member that actually rebuilds these CDI units? I'll try that swapping technique today.

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1972 H2, modified and Tracy bodied. 77 Kawi 1000. Lime green. Cafe. Lester wheels.

Zero, meet Jim ^ , Jim - Zero..........!

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"One day, your life will flash before your eyes. Make sure it's worth watching." : anon.

Wow, now that's lucky. I remembered someone remanufacturing them, but had forgotten who. I ohm tested my coil. That's all I'm able to do with what I've got. It's right at 8 ohms. I have six spare boxes that I tested per the manual and of them, five checked out. I removed my large and always in the way of a repair TRACY body and to my suprise, all of the CDI boxes on my bike also checked out. However, I found that when I tried to remove the center coil, the wires were barely touching and not at all snapped together. Maybe THIS is my "spark-no spark" Gremlin? I took the opportunity to clean up the wiring and route things better. I've ordered new coils from Jessbikes an I'll replace them all as a set and have spares. I'll also ground them very well. If my intermittant spark is still there, I'll start swapping boxes. In the meanwhile, I'll see about having a set rebuilt....

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1972 H2, modified and Tracy bodied. 77 Kawi 1000. Lime green. Cafe. Lester wheels.

The coil primary should be 0.64 to 0.96 Ohms. If it's really measuring 8 Ohms, it's bad. Here is a good test procedure from the resource site that requires only a battery and test lamp:

http://www.kawtriple.com/mraxl/cdih2/cditesth2.htm

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If it surges, that's normal, upshift.