Rear Cylinder not firing
Harley PanheadDiscuss Rear Cylinder not firing in the Classic Harley Motorcycles forums; I have a 1951 panhead, rebuilt 2001. Bought it 2 months ago. Aftermarket std heads. After changing out original distributor to a mallory electronic advanced distributor, the engine is only ...
I have a 1951 panhead, rebuilt 2001. Bought it 2 months ago. Aftermarket std heads. After changing out original distributor to a mallory electronic advanced distributor, the engine is only operating on front cylinder. Before replacing with new distributor it was rejetted and points regapped, but it still misfired on high throttle. Now, I took out the mallory electronic ignition and tried to get the bike to start with the old distributor, but it is firing on one cylinder only, when, it was firing on both before replacing with mallory. If you have sugguestions, Im open because I dont want to get ****ed by a mechanic fiddling with something. The timing is right, and the carb is clean. Need more info, just ask?
No, its nice to get a second opinion, I hope that is the case. Tomorrow I will give it a shot, I asked a mechanic earlier and he said the same thing, but he said it could also be something internal as well. I guess Ill find out tomorrow. Thanks.
I have not worked on a Pan, but... points, conensor, plugs, coils, are perty much the same no matter what the motor right?
So there might be a bad wire in there somewhere. the wires are multi-strands, and if all but one strand are broken, the wire could 'look' ok, but wont carry enuff current. Kinda an extreme example, but I have seen wires break within the insulation and look fine, but wont work. it drove me nuts till I found it.
could a plug wire have gotten damaged in the swap?
__________________ Scott aka Unclepsycho
Redneck without a clue
We were getting spark from both coils, but when we kicked her over she was only running on one cylinder.
Oh hay! you got this post in while I was posting the one above...
Hmmmm that changes things a little.....
So now, do ya got spark at each plug?
If so, then maybe a plug is bad??? I have seen bad plugs too. right outta the box, put in the motor and wont fire!!!! 3 out of 4 were bad,,, I couldn believe it, as simple as a plug is to make,
so if ya got a spare plug or two, maybe you could give that a try.
__________________ Scott aka Unclepsycho
Redneck without a clue
Is your Old Ign the Single Points or Two Points Distributor.?
I ran OEM Single Points Ign in the Pans I built in the 70's..
I have not used the OEM Two-Points Ign or a Mallory on a Pan so I cannot comment on That..
The Single-points Ign is Dual Fire.. If yours is Single Points Dual-fire then there IS juice going to the coil, it's just NOT getting to Both plugs..
Is the coil the old-style Screw-In the Plug wire type,,,, or a Plug-In the plug wire type.?
If this were My prob I'd check the Primary & Secondary resistance in the coil..
Make sure the plug wires are BOTH connected to the coil correctly..
If there is any doubt about the coil and even the plug wires try a Known Working coil and wires..
If the condenser went bad there would Likely be NO spark at all..
If yours is a Two Points Distributor then perhaps the second coil is bad or some connection or the Second Points is faulty or a connection there..
Other than those things there is nothing "internal" that I can think of to affect the one plug firing..
Jeeeeze--- you guys did ALL that posting in the few minutes it took me to type,,, WOW..
__________________ "Fill your hands you son of a bitch"
Rooster Cogburn
Last edited by frisco-rigid; 08-20-2009 at 12:41 AM.
Rear Cylinder not firing 
Linear Mode
