Atti2ude
Member
Lots of threads relating to one cylinder not firing but this is different. Bike started running rough during a ride and I’ve pin pointed it to the rear cylinder not hitting all the time. The problem is consistent and does it from start-up on regardless if the bike is cold or warm. All electrical/ignition components check out so now I’m leaning towards fuel or mechanical. Here’s what I’ve done so far:
1. Replaced Thunderheart ignition to programmable type.
2. HD dealer did a continuity test on coil and all checked out. I retested and get 3.5 ohms from both blue and yellow to red. I get 10K ohms from spark plug connector to red. I even switched wires around on the coil so if it were bad the problem would move to the front cylinder.
3. Replaced plugs and also swapped plug wires around. Pulled plugs and they are both firing.
4. Ran a jumper from ignition module rear cylinder wire to the coil to eliminate any wire harness issues.
5. Pulling the rear plug wire makes very little difference in idle but bike will die if I pull the front wire. This tells me the rear cylinder is hitting part of the time.
What am I missing?? Is it possible something is going on in the valve train or heads to cause this? There isn’t any unusual or excessive noise from the motor.
1. Replaced Thunderheart ignition to programmable type.
2. HD dealer did a continuity test on coil and all checked out. I retested and get 3.5 ohms from both blue and yellow to red. I get 10K ohms from spark plug connector to red. I even switched wires around on the coil so if it were bad the problem would move to the front cylinder.
3. Replaced plugs and also swapped plug wires around. Pulled plugs and they are both firing.
4. Ran a jumper from ignition module rear cylinder wire to the coil to eliminate any wire harness issues.
5. Pulling the rear plug wire makes very little difference in idle but bike will die if I pull the front wire. This tells me the rear cylinder is hitting part of the time.
What am I missing?? Is it possible something is going on in the valve train or heads to cause this? There isn’t any unusual or excessive noise from the motor.