Two cyclinders after it rained

[Geobob]

The short story is the bike started running on what must have been only two cylinders after is got rained on all night. I limped out to the interstate and ran it hard and the problem when away and has not returned.

 

I would really like to fix what ever the problem was but since it is no longer happening, it is hard to diagnose.

 

The bike is a 1988 Venture Royal with 69K on it. I have never replaced the coils or plug wires or caps.

 

I assume is was water or rain related since it went away after it got hot enough to dry everything out. It never completely lost the two cylinders, they would stop for a minute or two and then fire for a 20 seconds and then cut out again.

 

I have never had this problem before but I have also probably never had the bike out in the rain for so long. We were on a trip down the Blue Ridge parkway two weeks ago and we probably had rain every day of and on. By Tuesday night it had seen rain of and on for four days. I actually saw water pooling in the gas cap compartment. I noticed a drain hole in there. If than leads to the tank then I definitely got water in the tank. I noticed when I put the bike back together from a repaint, the small section of rubber was missing from compartment with the gas cap is. I'm sure water was getting in there than never has in the past. I thought that if it was water in the fuel it would have affected all four cylinders. So I'm not sure what the problem was.

 

So is this a common problem that all of these older bikes have stated to experience. If it is water/moisture getting into someplace it should not, where is the most likely. I have experience cracked coils or seen spark plug wires arc in the dark after wetting down the engine on a car.

 

I read someone post about water in the spark plug sockets. I actually had this problem on a 500 Vulcan. It had a deep hole where the spark plug installed and there was a drain passage in the cylinder head to let water out. Well sure enough it was clogged with dirt. Anything like that on the venture.

 

Any ideas of where to look first or should I start with hosing down the bike till it starts to miss fire.

[Peder_y2k]

The gas filler splash guard drains to the ground thru a tube. The spark plug sockets were originally sealed with a grommet around the plug wire connector. These grommets get hard and shrink over time and then water will enter and short the plug, so that's what likely happened. When parking overnight, I always use a bike cover....JIC

-Pete, in Tacoma WA USA

Edited July 4, 2014 by Peder_y2k
added comment

[Neil86]

Yes there are drain ports on the spark plug wells....if you remove the rectangular

plate (one screw) from the side of each cylinder, you will see the drain.

Make sure the engine is cold before removing the plate as it also covers the coolant drain plug and without the plate they can blow out under coolant pressure.

 

The gas cap fill area has a drain hose that should go to the ground...very small drain hole...easily plugged so check its clear too.

 

Was the tachometer bouncing erraticly during the misfiring...if so chances are the TCI

(ignition black box) was wet. Many have relocated the TCI to the airbox area so it stays dry.

[Venturous Randy]

I have a problem with my 83 getting wet around the area where the wires come out of the stator and it will misfire. I think it is the igniter wires breaking down. I carry a small can of WD40 in the bike and if it does not clear up pretty quick, I will pull out the rubber plug where the clutch bleeder is and spray down in the hole good and it almost always takes care of it.

RandyA

[Geobob]

Thanks guys, I think it probably was water around the front to plugs maybe. I did not get a chance to pull plugs or wire or check which cylinders were miss firing but it makes sense. Funny, I was joking that morning at the hotel about all the guys with there Harleys and how they travel with there bike covers. I guess I need to start doing that LOL.

 

One other think was the idea that heating up the water around the plug is what really caused the problem. I believe it was described that the water turned to steam once it heated up and that the steam is what caused the problem. This sounds like what happened. We left the hotel and headed country and about 1/2 hour later the problem stated to show itself and get progressively worse.

 

Interestingly the bike would idle and run at low rpms but midrange it would miss consistently and then at higher rpms it would intermittently fire. I guess if flood the cyclinders with the hose I might be able to get the problem to repeat itself.

 

I did not notice the tack fluctuating so I guess its not the TCI box

[Evan]

As long as have owned my 88, it has not liked to be power washed. Only had a misfire problem once from heavy rain, but many times from power washing. Have been told that this is fairly common.