V65 Plastic Alternator Cover

If I get caught in heavy rain, the V65 starts to mis-fire and generally play up until it’s dried out again.

I suspect there’s rain water getting in behind the alternator plastic cover. I removed the cover and the plastic extension and noticed (1) they don’t mate together very well leaving plenty of gap for water to get in and (2) at the bottom there’s a 2 in wide lip/gap.

Has anyone managed to seal the two piece together? Or is this a bad thing to do (I assume the gap at the bottom allows for the alternator to be cooled)?


needs to be open so the alternator does not melt, my monza ( same cover) used to miss fire badly when wet, fitted a dyna s ignition system and problem went away.

there should be a large gromet sealing the ignition and alternator leads between the spacer and cover

I assumed the gap at the bottom was to allow cooling. Re-fitted the cover yesterday and noticed even small gaps between the timing chest and the plastic extension.

Just wondering if the gap at the bottom provides sufficient cooling, whether I could seal the rest?

i would imagine  it cools via convection with heat rising.

i’d have a look at the condition of the ignition system and see if you have a poorly condenser or warn/miss adjusted points. My v65tt trail bike as same covers and ignition and never misses a beat near water

I wouldn’t block any gaps around the alt cover if they look like they’re deliberate. Guzzibear has a story about cooking wires cos he had an alloy cover on and no back spacer. Instead need to insulate the ignition sender gizmo.
Or could be a connector getting wet. (?)

PS: I’m assuming by the sound of it electronic ignition with the timing thingy on front of the alternator. (?)

Points and condenser get wet on really bad days with condensation and cause miss fires. Sealing top grommet to cables and cover can help, but the design or the ignition is a disaster!! My monza and TT have same setup and I upgraded to Dyna s on monza and will do same on TT soon