1 Dropping cylinders intermittently when warm. Probably coils? Sat Apr 11, 2015 7:54 pm
Rustybottom
active member
I've been doing a fair bit of searching on the forum and I'm fairly sure what's ailing my K, but I thought I'd run this past you guys before I start throwing money at the situation.
Got the bike with a dead battery, so in goes a fresh one and the bike runs great for the first few weeks. After fixing a number of other issues attributed to sitting improperly stored for a very long time, the bike started dropping cylinders after it had warmed up. Only at idle, it would run normally when put up to maybe 1500rpm, and ran famously up to redline. It makes a "Snapping" noise when the cylinder(s) kick back it. Sort of like a relay slapping over, or maybe just the coil arcing back? I have no idea, but it's prominent.
So, I have the bunk black tower coils installed, I've done the nighttime test to look for arcing, but didn't see any. I've testing the primary resistance, and got 2.9 ohms on both, but couldn't get a reading at all on the secondaries. I found a crack on one housing and patched it up with a bunch of JB Weld, and it may actually run a little better, but there are a lot of variables involved.
I'm guessing the coils are likely pooched, but I'm curious about the fact it runs fine until it's nice and warm. Do coils run more poorly when warmed up? Should I maybe try running with the coil cover off for more airflow and see if that changes anything before splashing out for new coils?
I do have a bad cranckcase hose that I've bodged with some form-a-gasket. I know that can apparently cause idle issues. But it seems unlikely to me it would cause cylinders to miss.
Thanks in advance for your advice, gang.
Josh
Got the bike with a dead battery, so in goes a fresh one and the bike runs great for the first few weeks. After fixing a number of other issues attributed to sitting improperly stored for a very long time, the bike started dropping cylinders after it had warmed up. Only at idle, it would run normally when put up to maybe 1500rpm, and ran famously up to redline. It makes a "Snapping" noise when the cylinder(s) kick back it. Sort of like a relay slapping over, or maybe just the coil arcing back? I have no idea, but it's prominent.
So, I have the bunk black tower coils installed, I've done the nighttime test to look for arcing, but didn't see any. I've testing the primary resistance, and got 2.9 ohms on both, but couldn't get a reading at all on the secondaries. I found a crack on one housing and patched it up with a bunch of JB Weld, and it may actually run a little better, but there are a lot of variables involved.
I'm guessing the coils are likely pooched, but I'm curious about the fact it runs fine until it's nice and warm. Do coils run more poorly when warmed up? Should I maybe try running with the coil cover off for more airflow and see if that changes anything before splashing out for new coils?
I do have a bad cranckcase hose that I've bodged with some form-a-gasket. I know that can apparently cause idle issues. But it seems unlikely to me it would cause cylinders to miss.
Thanks in advance for your advice, gang.
Josh
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An object at rest, CANNOT BE STOPPED!
1985 K100 cafe faired, 1978 Suzuki GS550