running on 1 cylinder
 

Hello all,I have been following this site for quite a while and have enjoyed the info on here.Now my faithful bike has a problem,Just recently it has been affected by rain,The last 2 rides on rainy days has after only a minute or so of riding,made my bike run on one cylinder,after a quick check,I found that it seems to be the rear cylinder as i can touch the rear pipe and find it cold.If i sit and wait by the side of the road with it running on just the front cylinder,It eventually seems to ,after a few minutes of heating up and drying, what ever seems to be wet, runs well again,till of course it gets wet again.It only does this when its raining.Other wise it runs great.When i got home after this latest adventure,I took the tank off and rear plastic and investigated the electrical.I suspected the rear coil wire and coil but ,Visually both looked fine.Twice the bike just died while pulling over to the side of the road but would restart and run on the front.It sounds electrical but not sure of the cause?Any ideas?I am thinking the only way of maybe testing this is to get a spray bottle,Start the bike and maybe spray down various electrical parts and see which one starts to play up?Anyways long post,Your ideas will be much appreciated.

chnage the plugs

The first place I would check is where the plug wire goes into the spark plug boot. They can easily be pulled half way out. I pulled mine, cut about a centimeter off and jabbed it back in. A zip tie around the boot will keep it from coming out.

Wow!Quick responses,Well i will certainly try your ideas but,It still runs fine when dry,Only when you add water does it run bad.Will further investigate sunday.

This has happened before to other members, and goes wayyyy back before the inception of this forum. The problem is with the tank vent hose. It's location allows water to enter the hose and then cause vacuum lock in the tank. Simply stopping and opening the tank filler will break the vacuum and the bike should run normally after that until the hose sucks up more water. The solution is to reroute the hose to another location or you could try cutting the end of the hose at an angle so that the hole is towards the rear of the bike.

If this does not solve your problem then the cause is probably electrical, but I'll bet 20 to 1 this is the cause.

Hmmm,Thanks for the tip Greg,Now which hose is the vent hose?There seems to be 2 hoses that could be vent hoses.{I know i should have a shop manual:nerd:}Well maybe i will redirect both of them.

Easy first step to finding water related electrical problems:

In a dark garage with your headlight disconnected and the engine running, spray a mist of water over the engine from a little spray bottle. You may find the problem this way, look for arcing around connectors, plug wires, etc.

Good luck.

Make sure you leave a door or window open so we don't read about the dead guy found in his garage with the motorcycle running.

So a update on the running on one cylinder problem,It finally rained today,so took my bike out for a spin,And she ran fine no hiccups at all.This is after i rerouted my vent lines.So a big thanks to Hawkrider and all the other members who offered up ideas.:D

I have been running into this problem on more than one occasion. this first time happened when i first washed my bike after having my shop remove the carcoal canister, rejet it, add two bros pipes and a B&M filter. It ran like crap for almost a week, durring this week i changed the plugs, drained my tank, added new good fuel. This is all after checking hydrolock. It still ran like crap with the tank open. Then one magical day it stopped and it ran fine. Until i was on a road trip about a month ago i got caught in the rain and it all happened again. I stayed four days where i broke down (clear lake ca) and drained my tank added new fuel and heet additive and went home. Didnt seem to run excellent but it got me home. Now im pissed and wont ride it.

Check for PVLIR (do a search). Also check for crimped or improper routing of fuel and vent lines.

I tracked down my fuel line vent and found that it was routed between my cylinders. Is this normal? i didnt like it and i thought that the flat spot would cause an air trap if water got in the line. I rerouted it to the left side of the engine and down the scoop. But it will be a little while before i get to test it. Thanks for the help i always use this site.

just to throw it out there but you could pull your plug boots off and check the resistors in there. they say those dont go bad but i had a simmular problem like yours and i thought it was the coils and come to find out it was the resistors in the plug boots. you can check them with a meter.

Just to throw my two cents in: I had problems with my bike in the rain as well, and found a fair amount of advice on this forum. I checked all the hoses (all clear), the electrical connections (greased/siliconed every wire I could find, from the plug wires to the starter motor wire, even the blinker connections), built an aluminum "spray guard" which I mounted so that it keeps water out of the front cylinder plug, all to no avail.

After the second attempt to fix the problem (read- after my second morning standing on the side of the freeway in the rain), I parked the bike in the driveway, started it, and sprayed it down with a garden hose for a few minutes- No stalling! Success, right?

No. Next day in the rain the bike started acting up again, but luckily it wasn't raining too hard and I was able to limp it home taking some side roads. As I was pulling the air box to check for electrical connections underneath ( I was at the end of my rope and convinced that the problem was electrical, since the bike acted like it was running on one cylinder) and noticed that the filter was wet. After looking closer I noticed that there's a plastic "diverter" in front of the air box that covers the area where the snorkel draws in air. It covers the space between where the frame comes together at the neck and extends down and back a bit. Problem was there's a good sized hole where the throttle cables pass through, almost 2"X2", just to the right of the air box snorkel.

I used some aluminum-backed all weather tape (the kind used to seal ductwork outside) to cover that hole and seal some other small openings (the plastic diverter is made up of a few smaller pieces that kind of snap together). I've ridden in some pretty heavy rain two different days since then with no problems so far.
I don't know if that hole is on all Superhawks (I've only got mine to look at, and haven't had it a year yet), but it's worth checking out if you've tried everything else.

My bike would run like crap, and as soon as I let off the throttle it would die. It would start back up with a little difficulty, but needed the same constant throttle to stay running, all the while sounding like a poorly tuned thumper. This only happened after riding about ten miles at freeway speeds in moderate rainfall. Light spray wasn't a problem, and riding in town was no trouble, which led me to believe there had to be a fair amount of water and it was being pushed somewhere that wasn't usually directly exposed to water.

Hope this helps someone, since this forum has helped me out and I'd like to return the favor.

I have a question... If this tank vent line was the problem, would I be getting fuel to the cylinder? I have a "one cylinder" bike right now, and it smells like gas in the exhaust... indicating that there is fuel getting to the cylinder. I know I'm running on one right now because one downpipe gets hot... the other stays ambient.

I am going to attempt a troubleshoot of the plug, plugwire, and coil to see if this is my issue.

So far my plan is

a) remove plug, ground and check for spark...
b) if no spark, move front plug to rear plug, still no spark?
c) move rear coil to front, and vice-versa to see if rear gets spark
and last but not least... if C doesnt get results... I have NO idea

Spark, Fuel, Compression...... find out which one is missing and go from there ;)

well if it smells like fuel, you're def getting fuel, in that case its ignition.

a weather coroded spark plug wire will arc to the adjacent metal. change the spark plug wires and see if it helps.

well just in case does anyone have a rear coil on the cheap?

One thing to check would be the plug wire to cap connection. After 48k miles on mine I found that my rear one was loose, running like shit, and had actually charred the end of the wire from arcing. This was found accidentally, I might add, when I bumped the wire and it came loose from the cap. I have some extra copper core wire and I may swap it out with this winter. In the meantime, I just cut off 1/2" and went with it. Works great now!