Intermittent miss

[Tando]

XB12XT with around 15K on the clock. Just developed an intermittent miss. It rides fine for first 20km or so then will give one cough, engine light on then straight off again. It will then do it approx. every 20-30km after that. Always just one cough. Otherwise all fine. Have checked for loose connections and replaced spark plugs.....about the limit of my mechanical expertise to date.

[Theycallmecrash]

The "cough" youre experiencing, may be normal, for a Buell. A "cough" or hesitation is quite common from a take off. Its a 45 degree Vtwin.... That means plenty left of the rotation, an open throttle creates a lean pop in the intake when done right after the rear cylinder has done its thing.

[Tando]

Thanks. It's never from take off. Happens cruizing regardless of speed. idles fine and has not happened at take off....yet! Has not done this for the 5K I have put on it since purchasing.....until this week.

[Theycallmecrash]

This is odd, but could remedy your issue, install a redundant ground wire from your battery's ground, to the ignition coils base.

The reason, is the engine has terrible grounding, and especially the cylinder heads, and a proper secondary ignition requires a straight path to ground. Or intermitent coil failure.

[user_deleted]

tando: agree with crash on the redundant ground but i would also order up a set of new plug wires and replace them while you're under the airbox base and doing your work. they are reasonably priced and many times will arc to ground and cause this intermittent miss. just a suggestion. also check the the lead and its plug which powers the coil. it must be secure and corrosion free.

[go cytocis]

will give one cough, engine light on then straight off againThis sure sounds like a simple intermittent break in the electrics as suggested above. You're sure you've got the battery terminals clean & tight?

[Tando]

Thanks all for your input. Will have a look at all those things when have time. Battery terminals are clean and tight. Negative was a little looose but have cleaned and tightened and no change. If the battery was getting a bit tired could it cause this? I have the battery tender on mostly but if I forget and leave it a few days it struggles to turn over.

[MnBueller]

I have the same issue Tando, and being new to anything powered by a big twin was also wondering if this is "normal"? Sounds like we both have some things to try. Good luck on yours...I will report back if it helps me too.