Cb350f ignition help needed, coils getting hot!

S

shaggycb750c

Active Member
Hey guys! With summer here, I'm really getting excited to get this bike running, but I seem to be at a stalemate. I've been working on this bike for a bit now and making leaps and bounds. Just yesterday I was able to kick it over for the first time(s) and amazingly it started and ran for about 10-15 seconds. I didn't try again as I noticed smoking coming from under the tank. Apparently it was one of my coils. The coils seem to be getting fairly hot without the engine being on. I've read that overheating coils are typically from the secondary side, but everything regarding the ignition is brand new, condensers, points, coils, plugs, wires and boots. The boots are NGK 5k ohm. Any ideas on what I should check? Anyone have a similar experience? Thanks in advance!
 
Coils get fairly hot normally, much more so when energized and the bike is not running. No way smoking hot though. With everything new, I'd double check my wiring and connectors. Smoking electrical is nearly always something shorted to ground when it shouldn't be.
 
If you can, after checking for burnt wiring under the tank, just rig up a container to hold some fuel like maybe even a turkey baster and tape it to the bars then start it up and see what smokes . . might also be some old oil or weeds or cob webs etc under the tank
 
I actually had the tank off and on the seat. The right (inner cylinder) coil was getting considerably hotter than the left. Think the resistance plugs could be a part of it? The coils are cb750/900 coils so that they have replaceable plug wires. More resistance=more heat.
 
Is this with the bike running? If not, then it sounds normal. Only one set of points closed, so only that coil is energized. Doubt that resistor plugs affect coil temp when running, but certainly not enough to get smoking hot if everything else is ok.
 
Yeah, if you are just leaving the key on for several minutes and the bike is not running, don't do that cuz its bad, mmmkay
 
I get don't leave the key on but I can imagine that it was never intended to sell a product that can overheat and be destroyed by leaving the key in the on position. Something must not be right... The bike was previously laid on its side for 15 years so I'm trying to get a non-runner running, so I don't really have a frame of reference of "running"... Yet...
 
OK you are incorrect . . in some cases on some vehicles, a coil will get hot enough to fry your finger . . . if your bike bis running and both plugs are firing, both coils should be nearly the same temp . . if one is blazing hot and the other is just mildly warm, there is a prob..
 
I get hot enough to even burn my finger but there's no way an engineer would let there being a product on the darn thing that would cause a part to fail by accidentally leaving the key on. People complain more of a dying battery than a fried cool over leaving the key on. I've started up a ticket on getting a replacement, maybe i just was unlucky. I'll swap the wires around and see how hot the other cool gets.
 
Who says engineers wouldn't design a part that if used improperly won't fail had who said you had a part that failed because you left the key on . . just because a coil getsd hit does not mean it is working improperly or will fail.

The pertronix I pick up units fail if you leave their key on and tgjose were designed by engineers . . ford had to recall and repair rear door latchesd on millions of vans because they would pop open all by themselves . . another mfg just had the biggest recall in us history a few years . . the list of recalls on parts that were designed by engineers stretched around the block serversl times.
 
OK, if you are just leaving the ignition on and not running the bike you better stop right now . . I told you to do the test with the bike running.
 
I haven't tried anything since the first day I created the post. I'm not here to get into an Internet arguement, I'm here to get my bike running. I appreciate your input. As I stated the bike isn't running yet, I'm trying to get that going. I think the one may have either failed or was just a defective unit. I figured a couple tests I could do was a current draw, as well as resistance between the primary and secondary coils. I at least have the other cool to get different results from.
 
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