S&S IST - Ignition trouble Harley Custom Discuss S&S IST - Ignition trouble in the Motorcycles forums; My shop is working on an '08 (homebuilt) Chopper. 124" S&S with the IST. Customer replaced everything ignition related and still no spark. I got it on Friday and now ...

[Forbidden Choppers Inc]

My shop is working on an '08 (homebuilt) Chopper. 124" S&S with the IST. Customer replaced everything ignition related and still no spark. I got it on Friday and now it's my problem. Any ideas? Already have S&S technical working on it.

[frisco-rigid]

Hi Mark

As I was reading it the first thing that came to mind is Ground..
You didn't tell us much so I gotta ask-------------

Does it spin but just gets NO spark.?
Did it ever run.? Start.?
If yes, Why did the cust. start changing things.?
If not, did the cust. wire the sickle originally & then rewire the New Ign. parts.?
Guessing that it doesn't even spin this is what I would do..
I'd check the switch.. Ohm check the coil.. Trace all wires.. Circuit Breakers/relays.. Battery.. Certainly look for proper ground.. You know,, Some guys forget to scrape paint for a good ground..

Perhaps,, before doing anything I'd install a Known Working Switch, Ignition, & coil & see if it runs..
If it still does not run,, OK, set him down and tell him you're going to wire the whole machine Correctly from GO..
Um, what did I leave out..???

Good luck Pal

[unclepsycho]

Keep us posted, I had a similar problem a few years ago with a guys bike. I too replaced all components, including grounds... bike would run, sort of then nothing. Before I could figure it out, the guy got mouthy about having no bike all summer,(3-weeks) so I "delivered" it to his front porch, and never got to finish the job. It has always bothered me to not figure it out.

Good luck.

Oh, like Frisco says , take a known set of parts and test the bike, I have gotten 2 sets of bad ignitions in a row before! What are the odds!

[Forbidden Choppers Inc]

My mistake.... (Rule 1) Give as much information to those helping so that we can get from "here to done" in as short a time as possible. My apologies.

It cranks over fine, battery shows 12.8 volts.

[aceharleywrench]

Does the IST have an ion sensor like the stock ECM? If so,a lack of compression will keep the plugs from firing.I found this out when a customer installed his own S.E, roller rockers & didn't relieve the webbing on the rocker boxes (the web was holding the valves slightly open) It's a long shot,but you never know.

[Forbidden Choppers Inc]

I'll check compression. The motor is 8 months old and has less than 1000 miles on it, but we both know any thing can happen. Thanks for the reply. I'll let you know what I find.

[Forbidden Choppers Inc]

After talking with the technical departments electrical specialist, it was agreed that I was to send the module and the secondary harness back to S&S. They received it today (Friday) and would be contacting me on Monday. I'll keep you posted as to outcome.

[Forbidden Choppers Inc]

<<<<< UPDATE >>>>>

S&S determined that the module was smoked. $404.00 later, I will be installing and testing the bike on Monday.

More info as it becomes available