OK we've determined through leak-down and compression tests that the engine is mechanically sound. So that leaves electrical, we had a module on our 120" that was not advancing the rear cylinder(single fire) it cost us 40+ HP on the dyno. When we changed it, the old girl perked right back up. Now if you are sure that you have no intake or exhaust leaks try this. First replace the wires with a new premade set. I say pre-made because i've seen numerous u-makem sets fail. then replace the plugs again and check the gap!! Next find a coil to try, and lastly try a new module. Having read all the post though I am leaning towards the Screaming Chicken module being bad.

 

In the past I've seen ign modules rev limiters break down like this shutting off a cylinder Replaced the mod and the bikes ran great again

 

Screamin' Chicken!

I had a set of spiral core wires that came with my Twin Tec ignition that I had to make up to fit Bertha from their parts. They ran OK, but were sparking against the rocker boxes. Replaced them with a $12 set of "Screamin' Chicken" wires from the dealer and all is well. I'll never make up a set of wires again, when premade ones are so cheap. Not worth it IMHO.

 

I could tell you horror stories about spiral wound plg wires It is halloween maybe I should

 

Do tell

 

OK I installed a DYNA 2000 ign in a 1993 stroked sportster Bike started right up customer took it for a ride and about 10 minutes into the trip the engine started to misfire He brought it back to the shop The next morn I started the bike took it for a run and it ran great maybe an 8 minute trip Customer took it again for a ride and let's say 15 minutes into the trip it started missing again Well after alot of short trips I experienced the misfire On the road I pulled the plugs to see if spark was there and low and behold the rear cyl had no spark Say 20 minutes later (bike cooled off ) spark appeared and got the bike back to the shop Anybody sleeping yet ? Called Dyna and one of the techs asked me what plug wires the bike had so it told him spiral wound He told me that customer feedback was telling them that suppression core plug wires should be used Well a good ending Dyna started telling the public in the installation instructions not to use spiral wound wires on their 2000 mods It was a learning experience for Dyna and me Well Pt you asked

 

That sounds like it was a pita but at least you solved the problem and was able to learn something.

 

Ok here's an update I received an stock module today from a good member here buttoned it all up and runs smooth as silk. So it looks like my module was bad. I think it was advancing the front cylinder and not the rear I hooked my timing light up to it and it still flashes more rapid on the rear then it does on the front cylinder so I guess this must be normal I don't know but I do know it is fixed Thanks to all and especially to
northgeorgiahawg for his generosity.

 

Yeah Buddy, I know the feeling of fixing this issue too!!!!

Good to hear. Honestly there should be no difference in the spark rate front and back cylinder. You may just get a better induction connection on one, and not the other.

 

here's another update on the issue with the timing light flashing differant on the rear then the front. I borrrowed a freinds timing light hooked it up and it flashes the same with his light tryed the same proccedure on his bike and same result mine flashes differant front to rear and his flashes the same so it has to be something up with my light.