ignition module problem

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Oct 26, 2010 | 09:31 PM

#11

allnwalters

Thread Starter

6th Gear

Joined: Oct 2010

Posts: 13

Likes: 0

From: Lafayette, IN

Gonna take it back tomorrow and have them look at it.

Last edited by allnwalters; Oct 26, 2010 at 09:45 PM. Reason: wrote the same stuff twice.

Oct 27, 2010 | 12:39 AM

#12

FLHTom1948

Cruiser

Joined: Feb 2010

Posts: 247

Likes: 0

From: Rosarito Beach resort

You need an expert to set the jetting where it should be, that's all. Your Dyno expert isn't so expert, after all.

Oct 27, 2010 | 06:42 AM

#13

Doug S

Road Master

Joined: Apr 2009

Posts: 1,123

Likes: 43

From: NJ

Your original post and description sounds just like mine, rear cylinder misses about every third time and kind of pops, mine only does it when cold. I had a long thread about this last year and tried quite a few things to no avail but since it only does it at idle and evens out when warm I'm ok with it.

Here is what I tried, all new intake rubber, carb serviced and rejetted a few different ways, compression good, leakdown excellant, SE wires and coil, check all electrical/ignition wireing, few different kinds of plugs(autolite coppers are great), changed the exhaust-(not related to issue). One thing I noticed on mine was the rear cylinder runs slightly richer than the front and like most EVO drivers, I maintain cold idle with the throttle lock and not the enricher, keeps the plugs cleaner.

None of what I tried fixed the rear cylinder issue and even when I fixed my intake leak there was no change. Did you put a cam in your's, just currious. If you get it fixed post back what it was, that would give me something to mess with this winter.

Doug

Oct 27, 2010 | 09:35 AM

#14

miacycles

Elite HDF Member

Joined: Sep 2007

Posts: 4,468

Likes: 12

From: Bluffton, South Carolina

Quote:

Originally Posted by allnwalters

OK so I just switched the inputs to the coil and left the spark plug wires alone. Now the fluctuation on the vm is on the front side and the rear is steady. The front cyl is running perfect and the rear is still stuttering, so that's not it. Also when i put my hand over the front pipe it always pushes out on my hand but on the rear pipe it i feels like it pushes out but in between puffs it sucks my hand up to the pipe. What can cause that?

A problem with the exhaust valve train could do that. Most likely the exhaust valve. Although the compression test would normally say no. Most likely it is hust "reversion" caused by that pipes length. the rear is shorter than the front. Without being there and looking over your shoulder, I would say the steady voltage reading is the switched 12V ignition supply. The one with the flucuating voltage is most likely the "impulse" wire from the ignition module that tells the coil to fire. I dont think I would worry about it. Rember treat the patient not the test results. Hope this helps.

Last edited by miacycles; Oct 27, 2010 at 09:48 AM.

Oct 27, 2010 | 10:55 AM

#15

allnwalters

Thread Starter

6th Gear

Joined: Oct 2010

Posts: 13

Likes: 0

From: Lafayette, IN

I have a stock cam. I think I'm gonna put a single fire ignition in and see if that helps, sense the pistons don't fire exactly opposite of each other maybe the dual fire is making the rear cylinder fire on the compression stroke or something IDK, just guessing. I watched several of the videos of other members sportsters on here and they all sound the same. I would like to hear one with the signal fire for comparison. I'm just the kind of person that if something seems wrong I have to make it right, just so I don't think about it all the time. I have a buddy with a 05 dyna and it sounds perfect at idle, doesn't miss a beat. I wonder if it has single fire ignition? I'll check into it.