Dyna S ignition failure?

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gg883
Cucciolo - the Lil Pup
Posts: 19
Joined: Sat Feb 12, 2005 11:29 am
Location: San Jose, CA - USA

Dyna S ignition failure?

Post by gg883 »

I have a 1974 Ducati 750 Sport with Dyna S ignition (circa 1988) and chrysler marine coils + new wiring, japanese switchgear and Honda fusebox. Last July I rode it from San Jose to Laguna Seca to the Moto GP race. That day it was extremely hot and took hours to get into the racetrack to park. I was stuck in heavy traffic with the bike idling in that hot weather. When I finally reached the gate the rear cylinder started cutting out. I parked and pulled the plug thinking it was a fouled plug.

Changed the plug after the race (about 4 hours later), started the bike and ran fine on both cylinders until about 5 miles down the road then rear cylinder started cutting out again. Pulled the plug again and cleaned it and started the bike again on both cylinders. This time I rode less than 1 mile on the freeway before my rear cylinder cut out entirely. Stopped halfway home and bought new plugs at auto parts store. Put new plugs in and nothing. Rode all the way back home on one cylinder. When I got home I pulled the plug in the rear cylinder and it looked brand new like it had never fired before, not even any color at all.

My first instinct was that no fuel was getting to the rear cylinder. I took my carburetor apart and everything is working perfectly on the fuel delivery side. I am running chrysler marine coils so I tested those and they test OK. Recently I started the bike and rode it to the shop and the bike ran fine on both cylinders! However the shop was not far away and it was not a hot day (remember, after the race the bike ran fine for about 5-6 miles). So I can only conclude that the rear cylinder cutting out is related to heat and the Dyna S ignition (having ruled everything else out).
Has anyone else had a similar experience?
gg883
Cucciolo - the Lil Pup
Posts: 19
Joined: Sat Feb 12, 2005 11:29 am
Location: San Jose, CA - USA

Update

Post by gg883 »

Sent my Dyna S ignition back to DynaTek. They just contacted me with test results. They found a faulty module. Since mine is out of warranty they are offering to sell me a new one for $69.
Not bad considering the $150 normal cost.

The Dyna S ignition worked fine for 18 years.
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