Topic: Heat and the Electronic ign Q?

[Don R]

 My 70 with the cam and ported 836 motor had done about 30 hard miles in the extreme heat last week. After being parked hot for a few minutes. I started up, rode a few blocks and the motor dropped a pair of cylinders, I limped along for a 1/4 mile or so heading to a pull over spot when it picked back up and rode fine the next 3 miles to home in town.
 I'm wondering if a pickup took a break, or it might have been vapor lock? It has a 2-fuel line petcock and both go downhill with no extra filters.
  Since someone will ask, it's a Pamco and the fuel is half LL110 av gas and half 89 octane no alcohol pump gas. I know since it fixed itself, we're just guessing but I thought I'd get some feedback.

[bryanj]

Depends which 2 dropped out if 1/4 or 2/3 ignition if 1/2 or 3/4 fuel flow

[Don R]

 Yup, it cured it's self so that means more riding to see if it does it again.

[madmtnmotors]

I believe I have seen heat related stress in my Dyna S ignition at the track. At one particularly hot test-n-tune session I was running back-to-back passes in rapid succession, and after about fifteen passes I started experiencing some partial ignition cutout. I had had about enough for the day, so I parked it and had no more issues that weekend nor have I had any more issues with it since.

[ANDREAS MILKE]

What kind of electronic ignition are you using?
I had problems with a dyna and a kokosan ignition, so I developed my own programmable electronic ignition.
If you want to look a little more on the subject:
http://forums.sohc4.net/index.php/topic,186952.msg2211376.html#msg2211376
Regards,

Andreas

[ekpent]

Don I have had a couple problems/incidents with my K4 this year and last where when parked in the hot sun and started up and ridden it acts like its running out of fuel till I crack the cap open a little, it clears quickly and runs fine when I close it up. I can hear it hiss but the vent on mine might need attention.

[Don R]

 It appears my gold bike had a plugged gas cap vent, this issue was the blue/green bike and it's a Pamco ignition that I robbed from a bike that I bought for a member here. That thing would kick start with nearly no battery at all. We decided I would re-sell it. L0L. 

[PeWe]

Good to know what bad vent can  do.

[PeWe]

….........
I had problems with a dyna and a kokosan ignition, so I developed my own programmable electronic ignition.
..........

-How did the ignitions fail?
I have read about Dyna-S where 2:3 suddenly died. Usually an earlier version.

Interesting to know if it was a sudden permanent failure affecting one coil, 2 cylinders or if it were intermittent misfires.

I have thoughts about coils not grounded to frame and if ensure coils grounded will help.
The mounting screws attached to brackets, the front assembly point in frame can get grounded.
If an intermittent ground potential difference cause signal to spike/surge and damage the ignition electronics.