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Misfire in the rain.

2218 Views 3 Replies 3 Participants Last post by  52k
Wasn't exactly heavy rain but I'd ridden on a bit of muddy woodland and then out onto the road during a bit of British drizzle. Suddenly whilst under power the mother of all mis-fires. 50% down on power and felt like the bike was going to stall if I backed off the throttle to idle.

Clearly something was getting damp, my concern was that it was something like the ECU and I didn't want to be stranded so nursed the bike home for 5 miles or so before stopping to check it over properly. First place I checked was the HT leads and sure enough the front lower (front facing) lead was sparking out to the cylinder head. I rotated the cap a little to move the lead (end of the elbow) further away from the metal of the cylinder head and it was sorted, bike back to normal.

In my experience, once something has started arcing out it will do so again so there may be a tiny crack or something. The bike has done 1000 miles. Anyone else had any problems like this and or recommend a decent set of HT leads? Years ago I remember changing HT leads when problems like this occurred on old cars. This is a 5 month old bike so I guess it's faulty. I've got the race map running with Termi so this will almost certainly up the HT voltage a bit as part of the map but still it shouldn't arc out.
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Your HT voltage is not higher because of the different map, that's not how it works.

You do have a problem though, most likely a bad HT lead to plug cap connection. May be just a matter screwing the cap on the HT lead another twist.

Tell your dealer, this should not happen.
A small tin of WD40 or Duck Oil is your friend, a quick spray around the plugs, ht leads and coils should help if its wet as these displace moisture and help to prevent the energy tracking out. If its really muddy and wet stop the motor, remove the plug cap from the plug spray and wipe plug and leads clean then refit and spray should do the trick unless there is a deeper problem.
Cheers guys, I'll certainly try the extra twist on the HT lead and yes, already doused it in WD40 to displace any water. Hopefully this will be the last of it, but yep will certainly mention it to the dealer and if it happens again I'll get them to replace the lead.

The comment about spark voltage by the way was from previous experience from with an ECU map which I had modified on a turbo engine. It might have been spark duration (I can't remember) but the spark had definitely been increased. It may well be as you say that in the case of the Ducati there is no change at all to the spark but as you rightly suggest, it definitely shouldn't happen.

Thanks for the replies guys. Was also curious to see if this was a common problem with this bike.
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