Troubleshoot help. No Spark R90/6

[jjwithers]

A friend of mine solicited my help... and this is a bike with some custom wiring that I am not responsible for.

His bike was running OK, but as it got hotter on a ride, it would start to sputter.
Then his rides got shorter and shorter, as the sputtering got worse, sooner.
Then it completely died. No spark anymore.

Carbs are OK. I went over them with him 2 months ago and had it purring like a kitten.

His bike was running with a Dyna green coil, NGK wires, two plugs into the single coil. He has a Dyna electronic ignition.
W9 plugs in there (i replaced them with W6).
I replaced the green coil and spark plug wires with some original spare coils and wires that I have lying around. Still not a spark

I'm wondering if the electronic ignition or dyna booster died?

Any ideas on how to trouble shoot this one?

[George Ryals]

http://www.euromotoelectrics.com/v/vspf ... ngines.pdf

If the points are opening, bypass the booster and see if you get spark.

[Kurt in S.A.]

Dyna ignition and also a Dyna booster? What's the purpose of that? If you have the electronic ignition, you don't need the booster IMO. I thought the booster was used in a points situation to help keep the load down going through the points.

Kurt in S.A.

[jjwithers]

The booster comes with the electronic ignition. They are both installed on the bike. I have the same set up on my R100S.

If one or both are dead, how can I check?

[Kurt in S.A.]

I have the Dyna III on my /7...no booster...still don't understand why you need the booster with an electronic ignition.

Kurt in S.A.

[jjwithers]

It's how they sell it, and has the directions to install it. i always thought it was to regulate the current and advance curve from the ignition to the coil.

FWIW, i am not getting any power to the lead on the coil... so i'm tracing wires at the moment.

[Kurt in S.A.]

Snowbum talks about the boosters...it's for points bikes and it helps control the current coming across the points, keeping them from arcing or at least from burning out. The electronic ignition (Dyna III anyway) has no points...the Dyna box/brains is just an electronic switch which replaces the points. The booster has not advantage in that setup.

Hope you can find the problem somewhere else.

Kurt in S.A.

[jjwithers]

OK, got it going. A ground was disconnected going to the coil.

I ran the bike for about 20 min, it ran great.
Then fired it up about 45 minutes later and 1.5 mile away, it started to seem as if it was choking out.
It feels fuel related. I'd let the bike sit for a few minutes, fire it up, it would get me a few blocks and then die. Then repeat. I hotwired the bike running a positive wire from the battery to the lead on the coils and had the same results. so unless it is timing, I don't think it is the ignition. I did a basic timing and while trying to start it, just using the starter, the OT mark was in the window as expected. I can't rev it to check it at 3500 RPM.

[Zombie Master]

Sounds like coil to me.

[jjwithers]

Sounds like coil to me.

That is why I switched out the coils and went back to stock.
The fact that you say that makes me think it is one of the two items I did not replace, the booster and the electronic ignition.
If it is not fuel related, I have a feeling it is one of them...