NiftyHalden
MG fanatic working on a twin.
Alright guys, I'm in need of some guidance.
(Apologies, this got long)
I'm SO STINKING CLOSE TO putting this bike on the road in time for the great spring riding weather here in East Tennessee, but I've been going round after round making the last step to "completion"...
For a little background, I stripped the bike down & did paint and deletes and all this fun stuffact, and then wired the thing from scratch for just the necessities.
Well, here I am, scratching my head. I'm missing on the right cylinder about 15-20% of the time. I initially blamed cheapo bits in the carbs and redid them, but that did nothing.
Well I finally took the timing light (strobe light) to the thing after I had confirmed that I'm getting spark, and sure enough, you can watch the strobe light miss along with the sound of the miss! Bingo!
I know my timing is spot on, and the thing runs down the road fine aside from this miss, but the miss gets worse as the bike gets warm, and the cylinder will nearly quit at idle if I don't stay on the throttle. It won't quit completely as long as I keep the revs up, at least it hasn't yet.
I went through the entire ignition system with my trusty Fluke the other night, and came out as clueless as I started. I hit every single connector with dielectric grease, checked my grounds, cleaned the points & checked the connections to the springs, checked them for possible shorts VERY carefully (and again in the dark watching for stray sparks), swapped out a new spark plug, swapped condensers, then swapped plug wires from one side to the other and the trigger wires so it would start, and the miss moved to the left side.
So I narrowed my issue down to the point or the coil. In the dark you can see the spark in the points, and in the right one it's weaker & inconsistent, and fails visibly when the thing misses. Let me just say again that I swapped the condensers and the issue did not move to the other side.
I re-checked for shorts, wrapped all the connectors in electrical tape just in case, trimmed and re-seated the coil end of the plug wire, re-checked the connections at the coil, held the points wires away from the head, no luck.
Metered out the coils with everything disconnected, they were both in spec according to DCC, but they were different by about .4k Ohms. I'm out of town and away from my notes and can't tell you which coil had the higher reading or exactly what it was, but I felt like it was alrigt.
The battery was at 12.5v when I started for the day, and 12.6 when I gave up.
Since I went through all this, I've realized I didn't check my voltage at the battery with the thing running, but I know it was charging well when I first got the bike back together. It does have a new rectifier, and a roughly 1 year old battery.
At this point I'm at a loss. Do I just replace the suspect coil? I have a hard time believing it could be the point now that I've checked it's connections & cleaned it's surfaces...
Any opinions are really appreciated!
(Apologies, this got long)
I'm SO STINKING CLOSE TO putting this bike on the road in time for the great spring riding weather here in East Tennessee, but I've been going round after round making the last step to "completion"...
For a little background, I stripped the bike down & did paint and deletes and all this fun stuffact, and then wired the thing from scratch for just the necessities.
Well, here I am, scratching my head. I'm missing on the right cylinder about 15-20% of the time. I initially blamed cheapo bits in the carbs and redid them, but that did nothing.
Well I finally took the timing light (strobe light) to the thing after I had confirmed that I'm getting spark, and sure enough, you can watch the strobe light miss along with the sound of the miss! Bingo!
I know my timing is spot on, and the thing runs down the road fine aside from this miss, but the miss gets worse as the bike gets warm, and the cylinder will nearly quit at idle if I don't stay on the throttle. It won't quit completely as long as I keep the revs up, at least it hasn't yet.
I went through the entire ignition system with my trusty Fluke the other night, and came out as clueless as I started. I hit every single connector with dielectric grease, checked my grounds, cleaned the points & checked the connections to the springs, checked them for possible shorts VERY carefully (and again in the dark watching for stray sparks), swapped out a new spark plug, swapped condensers, then swapped plug wires from one side to the other and the trigger wires so it would start, and the miss moved to the left side.
So I narrowed my issue down to the point or the coil. In the dark you can see the spark in the points, and in the right one it's weaker & inconsistent, and fails visibly when the thing misses. Let me just say again that I swapped the condensers and the issue did not move to the other side.
I re-checked for shorts, wrapped all the connectors in electrical tape just in case, trimmed and re-seated the coil end of the plug wire, re-checked the connections at the coil, held the points wires away from the head, no luck.
Metered out the coils with everything disconnected, they were both in spec according to DCC, but they were different by about .4k Ohms. I'm out of town and away from my notes and can't tell you which coil had the higher reading or exactly what it was, but I felt like it was alrigt.
The battery was at 12.5v when I started for the day, and 12.6 when I gave up.
Since I went through all this, I've realized I didn't check my voltage at the battery with the thing running, but I know it was charging well when I first got the bike back together. It does have a new rectifier, and a roughly 1 year old battery.
At this point I'm at a loss. Do I just replace the suspect coil? I have a hard time believing it could be the point now that I've checked it's connections & cleaned it's surfaces...
Any opinions are really appreciated!