79 shovel.Crane Hi 4 Ignition,Drag pipes S@S SuperB. myProblem is bike seems to die at hi rpm almost as if ignition was shut off. accelerates hard right up to ready to shift then shuts down and backfires out the exhaust any ideas what this could be ign mod coil ground any ideas is great although i dont think its carburation[&:]


thanks

 

could be your not getting enough fuel to the carb, fuel filter ? or the petcock screen ? too small offuel line ? sounds like the bowl is draining faster than it can fill it up. maybe, just a thought.

 

bump

 

does the Hi 4 ign. have a rev limiter? the fact that it's backfiring out the exhaust sounds like the ign. is cutting out. check for problems with the wiring (shorting in the primary circuit maybe?)

 

Primary Circuit?? Not to ask a stupid question but whats that..

 

The wiring from the negitive side of the coil to thetriggering device.(ign. unit in your case). Just as a heads up, I have seen problems like this caused by tachometers. you might want to just disconect the tach.( if you have one)from the negitive side of the coil and see what happens.

 

It does sound like a rev-limiter but:
In the past, I have had 2 of the Hi-4 coils go bad on me. They would be fine up until I was in the middle of a trip. Then it would seem as if I wasn't getting fire to both cylinders. Took me a while to figure out that a defect in the coil was slowly eating the plug wires. After the 2nd one, I went back to points, dual-fire, and Accel coil.
Crane should stick to grinding cams.

 

I've run the little DynaS breaker for 10 yrs and had no problem, beats hell out of points. Did experience a similar situation while accellerating up to 90 mph, cut out completely but was able to get it running w/throttle(accel pumping) til I slowed to 60. Happened only once, must have been a clog at petcock, could not repeat. Thought ign at first, but when pumped is started running so it must have been fuel related, possibly stuck float needle. Good luck!

 

Yeah, I have had the same Dyna S on my 89 FLHT since it was like 3 months old. the only problem I have had with ign. was with a Dyna rev limiter I installed after a missed shift caused a little valve stem seal problem. I removed it about a year ago due to intermitent no starts (that was a hard one to find, evey time I lifted up the tank to check for coil trigger itwould start, turns out I had the rev limiter grounded to the tank bolt, and dummie me took about 3 hrs to figure this out.)
I have never been muchof a fan of crain or accel.

 

I have similar problem with 81 shovel. Happened a month ago with Keihen carb. I put on S&S Super E & thought problem was solved. After 2 tanks of gas it happened again. It does restart & if I keep it at 60 mph & don't get on throttle I get home. I suspect the petcock screen is the culprit but now I am considering coil. Would rpms have anything to do if it is petcock?