Bad Coils

[super googan]

Add me to the list of members with a failed coil. Bike has had an intermittent stumble or hiccup at low rpm for a longgggg time. Never could trace the problem.
When the issue was minor the temp difference between all 4 cylinders was only 20F. Last week she started sounding like a triple at idle and low rpm but would clear up at higher rpm. Checked the cylinder temps at idle with a laser temp gun and cylinder #1 was running between 30F and 80F cooler than the other cylinders.
New coil and a new plug and she's idling better than ever and running great. I suspect that coil was slowly failing since the day I bought the bike ( new )

Many have recommend a wet paper towel to check cylinder temp but trust me if the problem is intermittent or slight your not going to be able to tell a difference between 20-50 degrees. ( I couldn't ) The wet paper towel is only going to show a severe temp difference.

Oh ... and the coil tests within spec on the ohm meter. Dont trust an ohm test for an intermittent problem

 

[loosenut]

I am the one that posted about the paper towel test. It really only works if you have a coil failing at cold start-up idle. The three firing cylinders will heat the headers fast enough to find the failing coil. I keep testing until i start getting a sizzle. One had no sizzle. I moved that coil to another cylinder. The non-sizzle followed. I have since purchased an infared thermometer with laser for aiming as it is far superior to a wet paper towel.