No spark front cylinders

[Guest]

Howdy all

Please assist if possible. I have no spark in the front 2 cylinders of my 86 Aspencade. Before I buy new coils is there anything else i should check?

[Guest]

Well, here i am relpying to myself!

I left out some info. Front cylinders are only dead at lower RPM. Bike runs great and very ridable above 2500 rpm or so........

[Oldman]

If my memory serves me right, one coil fires the front 2 cylinders, while the other coil fires the remaining 2. Each coil has 3 wires, one for load leading in, one for ground going out and of course the spark plug wires. I’d start with making sure that one of those wires didn’t get pulled off, rendering the coil useless.

[Guest]

Thanks Oldman
just had it all apart and back together. No bad wires or connections that I can find. Back together and runs exactly the same. 2 front cylinders dead at lower idle.

[Guest]

The pulse generators send the signal to the control unit which drives the coils. The pulse generators are under the timing belt covers on the '86.
Generally speaking, the PG's either work, or they don't. And are more likely to break down under heat.
Do you lose your tach, or only spark?
The PG's that drive #1 and 2 also send the signal for the tach. If it works, then the PG's and CDI can be eliminated and you need to start looking at connections and voltages supplied to the coil.

[Guest]

Hmmm......your impressing me now! I did notice recently the tach was disfunctional. Although I can not say it stopped working exactly at the same time this issue started it was very close to the same time.

[Guest]

Upon further thinking.........the tach works but it is the tach indicator, the bar beneath the tach, that is not working. I may not be calling it what it is.

[Guest]

The red bar for the tach is controlled by one of the buttons on the center pad of your handle bars. I think it's just an on/off toggle.
Are you sure it's spark that your missing? You've pulled the front two wires and cannot get them to arc?

[Guest]

No spark in the front 2 cylinders at all at idle. Apparently spark starts firing at some point as the RPM's get higher. All of the sudden she will go from sputtering to a rocket ship in the 2000 - 3000 RPM range all the way to redline.

I'll look over the instrument panel for that switch for the tach bar.

I appreciate your thoughts.

[KnoxSwift]

gibbycade, did you ever figure out your problem?

I think I'm having a similar issue.
I'm stumped on troubleshooting and now just throwing parts at the thing.
Which obviously isn't going well.

I can't tell if I'm not getting a spark I have a spark pen and it indicates all 4 cylinders are working at idel but I have a backfire through the carbs on the #2 that I've not been able to figure out around 2000RPM. I'm thinking the front two plugs aren't working efficiently at that RPM? I bought some used coils and making the change to automotive plug wires...but before I just throw more parts at my problem I read your thread and wondered what happened with your no spark?