Left bike in rain and now it's running like crap

[patleeman]

Hey guys

I did some digging around but I couldn't really find a conclusive answer to my problem.  I have a 2000 GS500E with about 5000 miles.

I rode my bike to class the other day and ended up leaving it parked outside in a drizzle all day long (approx 12 hours).  When I got back to the bike it would start with choke on but the minute I gave it some throttle it would immediately stall out.  If I eased on the throttle a little bit the revs would increase until about 6000.  Once I left off the throttle it would ease back down to 3-4000 (with choke on) very slowly.

The bike kept stalling out and would not transfer power to the wheel (would stall out) even with choke on and revving up to 6000.  I left it with choke on for a while and after about 30 minutes I was able to limp to a gas station.  I had suspicions that I had gotten water in the tank (This has happened before once when I washed my bike.  I really doused it (first time washing the bike) and it displayed the same symptoms*).  Luckily I was at about half a tank and topped it off with fresh gas.

I let the bike idle for a while and after a while I was able to ride it home, but it ran like crap.  Some of the symptoms included sputtering, engine speed slowing dramatically when given sudden throttle, loss of power.

I got it home and left it in my garage until this morning.  I got on, it rode fairly well, still had problems but I was able to make it to work.  I have suspicions that I may have a leak in my gas cap and water was able to make it into my tank (threw about 10 oz of isoprothyl alcohol in the tank about two hours ago to try to "dry" the gas out).  While riding it today after I left it parked on a hill at an angle for an hour (stopped off at school) it displayed the same symptoms as yesterday and even backfired a few times.  Once it warmed up though the issues stopped.

Could it be something else? 


*when this happened the first time my buddy and I ended up draining the gas from the tank and topping it off with fresh gas.  This was after we left it in his driveway for a few days.  This is what aroused my suspicions that it could have been bad gas.


P.S. Long time lurker, this community is so amazing and full of information.  Thanks in advance!

[BaltimoreGS]

Gas is a possibility but next time it happens pull off the spark plugs one at a time to make sure you are running on both cylinders.  Water could be getting into the electrical system.

-Jessie

[patleeman]

I didn't think to do that.  Do I just yank the spark plug cable off or something? Or do I actually unscrew the spark plug?

Thanks for the help!

[BaltimoreGS]

Just take the plug boot off the plug.  On a normal running bike, the engine should keep running (albeit roughly) and smooth out once you reattach the plug.  If the engine dies when one plug boot is removed, the opposite cylinder is not working.

-Jessie

[runabout879]

I was thinking along the same lines. Possibly water getting to the coil? I haven't had a chance to really tear into mine to see where the coil(s) are, but it could definitely be the issue.

[gsJack]

Any problem I've ever had with a wet engine missfire on a mc has been the spark plug wires shorting out.  On the old Hondas it was water in the hollow plug caps requiring new caps.  Never had a problem on the 97 GS for 80k miles but I've had it on the 02 GS on one cylinder since early on and it was/is a spark plug wire that's loose in the coil.  When new the wires are screwed into the coil and bonded tightly in place.  If one comes loose it will eventually short out running in the rain or sometimes just sitting there on a wet day.

Check to make sure the plug wires are tight in both coils and can't be turned by hand with considerable effort.  If loose just cut off about 1/4" and screw it in tight, best to put a big dab of dielectric grease on it before screwing it in.   On my 02 GS I trim it or replace it about once a year when I check valves.

For a temp fix to just get home on a wet day you can grab the plug wire as high as possible and turn it clockwise until it is tight.  You can check it like Jessie suggests above to determine which cyl is missfiring.

[patleeman]

Thanks for the help guys, I think it could be a faulty coil.  I pulled one of the spark plugs the other day and it ran for a second or two then died.  Going to check the connections.