For a while, I have suffered a serious misfire after going over a bump. Restarting has cleared the fault. However, today, the fault did not clear, and I have limped home. I am assuming a loose contact, and am starting with coil contacts. Any suggestions of what might be causing the problem?

Hi Stuart,

From another UK resident - Welcome to the forum.

You could check to see if the the HT lead connections to the plugs are secure. They sometimes are not pushed fully home, so can cause that sort of problem.

Also check to see if the ECU cable is fully seated.

Mike

mike is right on the money stuart ....

and welcome to the forum...

lots of us have experienced exactly those issues at one time


a close inspection of the plug tops might be a good idea .....a lot of spark plugs these days do not come supplied with ferules which make the plug to lead connection to 5 odd mm ... we have seen many without these ferrules and just the thread visible (3mm) and the gap between the high tension lead to spark plug is quite remarkably loose and the lead clip showing major pitting around the metal where the connection should be made .




cheers

Thanks guys. Having checked and cleaned HT and LT leads at coils, the bike is running, but not quite smoothly. I notice that I inadvertently swapped the coils over. Are they identical?

yep sure are stuart .. did you do any measurements of the lead resistances ....high tension and low tension of the coils ?

No, haven't got the gear, and pig ignorant about electricity! Prior to today's fix, it was running smoothly between misfire incidents. Now it's not having misfire episodes (so far) but just feels a bit rough.

there is an excelent article about multi meters on the forum here by kbike

i really recommend a thorough read of it ...you will be needing those skills soon enough ...unless your pockets are deep and well full

Thanks. Time I learnt a bit!

Stuart....I see in your earlier answer that you cleaned HT & LT at the coils......only?........

As Charlie mentions....did you remove the sparkplug caps, and checked that you got the adaptors installed?
It`s quite common that they are missing....and resulting spark erosion and corrosion at the connectors inside the caps.

Just asking, you might have overlooked it.

Inge K.