Low RPM trouble when it rains

[Rubin]

I have a quick question for all the electrical experts out there. It seems whenever it rains and the bike gets wet, there is a massive lag at low RPM. The bike will run fine if I keep the RPM's over 5000, but will stumble and try to stall out on me below that. I am guessing I have a short somewhere, and assume it is the plug wires. Could this possibly cause this?

[DGXSER]

Do you have the POD type filters? Yes, there is ALOT of opinions both ways as to this being a factor or not. Also, is the bike good and warmed up, do you tend to run lean?

In my experiences, electrical stuff either works or it don't. Typically it is not RPM driven and certainly never gets better with higher revs or more being asked of it. JMHO.

I would think vacuum leak sucking water in? or lean mixture and the choke is in but engine being cooled off from the water causing it to run bad.

[The Lorax]

could be your plug wires are marginal and are shorting to something, happens to me when water falls from the sky. next time, run your hand along the bottom of the tank near the wires, you'll find out REAL quick if there's a short, have a nice day and ride safe

[bikerphil]

Could also be the spark plug caps.

[webbcraft2150]

Or, fire it up and spray water on the wires and caps as its running. That will show ya quick if its wires or caps or a vac leak or your pod filters are suckin water. A good dose of die-electric grease in the plug caps may help to. Make sure you have to little boots on the end of your plug caps and they are not cracked. 'Course feeling the wires while your running in the wet would be a good show!

[Ivan]

checking the secondary ignition system for problems is easy. Just use a spray bottle (old windex bottle or something) and mist around the coils and wires. You will hear the bike miss if there is a problem.

When you determine that water is effecting the system, usa an ordinary 12v test light clipped to engine ground and slowly move the tip around the wires and caps and such until you find the spark escaping, which will br fairly obvious.

[Rubin]

Thanks for the replies!! Well, I tore into the wires and recapped them. They were a little long when I installed them anyway, so two birds with one stone and all of that. Sure enough, there was barely any di-electric grease left on the caps. Next step will be the water on the wires trick to isolate the problem as being there. I am hoping that is it and a little grease will do it. I will let you know how the test goes.

[Ken Talbot]

Check where the pick-up coil wires come out of the left side engine casing. You could be getting a bit of water wicking its way in there, and finding its way through a minute crack in the insulation on one or more of the wires where they are held by the crimp fitting just before exiting the case. This has the same effect as a broken pick-up coil wire - you suddenly, and often intermittently, lose two cylinders. In this case, the wires themselves may not be broken, but water around the cracked insulation could be letting them short out as the wires flex with operation of the vacuum advance mechanism.

BTDT.