[Rainman]

My bike runs great. Its a little hard to start with the electric starter but starts on the first kick. Anyways, my bike sputters and loses power when I go over washboarded or hard rock-packed roads and large bumps. It loses power and then after the washboard area it comes back to life again. I know that there could be a million possible causes, but I was curious if anyone could shed some light on the subject. I know that its NOT my kick stand switch. I have good gas in it and all my fuel connections are tight. I have read about the gas cap vent. Does anyone actually know where it vents from? I do have a tank bag strapped tightly to my tank and it covers the cap. Could this be the problem? The weather hasn't allowed me to go out and test it without the bag yet. Thanks.

 

[lizrdbrth]

Just loosen the cap and ride it. If the problem goes away your vent is clogged.



As you said, this could be a lot of things, but since you say it only happens on washboard roads I'd take a look at wiring first. Loose connectors, bare or broken wires, particularly near where they enter the left side cover and where they pass through the frame before going under the seat, and all the CDI connectors under the right panel.

 

[PJungnitsch]

Might want to look under the tank at the coil connections as well. Just for maintenance I'm slowly taking all my electrical connections apart, shining them up with sandpaper or a file, coating them with a bit of Vaseline or dielectric grease, and then making sure they go tightly back together.

 

[jbfla]

My guess is that it is not the gas cap vent. If it were, your bike would not start running good again after the bumps. When you open the gas cap, you would hear a whoosh as the air rushes into the tank.



Possible cause: most likely, loose connection, intermittent electrical/ignition problem caused by the bumps.



Less likely,... a fuel problem. The main jet may not pick up fuel from the float bowl due to a low fuel level, dirt in the bottom of the bowl, and sloshing around of fuel due to the bumps. I am skeptical that all these conditions would happen every single time you hit the washboards but it's a possibility.



jb

 

[phelonius]

I used to have that problem on two stroke twins about 40 years ago. I thought maybe better carbs had eliminated it.



Phelonius

 

[Rainman]

Thanks for the replies. I'm thinking loose connections as well. I'll dig into it when I get some time. Any further help would be appreciated.

 

[thumper]

Thanks for the replies. I'm thinking loose connections as well. I'll dig into it when I get some time. Any further help would be appreciated.

I went for a ride today on a really bumpy, tree root, pot holed type road. After I hit several large bumps the bike died and coasted to a stop. I tried to start it and it just kept cranking. I had gas, spark, etc.

I opened the gas tank and got the whooosh sound! Started right up. I'm thinking the warm day, and all the bumping caused the gas tank to swell a little or the vent got clogged. either way, removing the cap fixed it.

 

[phelonius]

So I guess you are saying your gas tank sucks?

Why do you suppose the malady manifests itself when going over bumps?



Phelonius

 

[thumper]

So I guess you are saying your gas tank sucks?

Why do you suppose the malady manifests itself when going over bumps?



Phelonius

no comment

 

[Gerry]

This is not a lewd joke, but are you sure your tank was sucking and not blowing? As I read your 'problem' the symptoms reminded me of how my Dunebuggy acted when I had the floats on carbs adjusted to high. Now, should the fuel be under the slightest amount of pressure, the situation would be even worse as fuel may be 'pushed' pass a partially seated needle. Just a thought cause the buggy (VW) ran very rough (flooding) when on rought surfaces until I (yet again) reset the float height. I have since read that the Weber ICT's were very sensitive. Gerry

 

[thumper]

This is not a lewd joke, but are you sure your tank was sucking and not blowing? As I read your 'problem' the symptoms reminded me of how my Dunebuggy acted when I had the floats on carbs adjusted to high. Now, should the fuel be under the slightest amount of pressure, the situation would be even worse as fuel may be 'pushed' pass a partially seated needle. Just a thought cause the buggy (VW) ran very rough (flooding) when on rought surfaces until I (yet again) reset the float height. I have since read that the Weber ICT's were very sensitive. Gerry

Gerry, you may be right. All I know is my bike has never just died like that before. I was going up mt hamilton, riding pretty briskly and saw a young girl on a ten speed on the side of the road. I shut off the throttle quickly and pulled over and the bike just died. I helped her fix her flat and then my bike would not start. I removed the cap because my old 56 K model sportster use to suffer from vacume lock on hot days too. Mine could have been all of the above problems.

Hope all is well with you, have not heard from you in a while.

IGOFAR

 

[dalsco]

Another possibility that hasn't been exactly stated that has happened to me is a loose spark plug, the bumps rattle it around messing up a good ground on it... Just another thought?>?>?

 

[heyduke]

I had the same problem with my TW. I talked to the tech at my local dealership because it sounded like one of those problems that don't happen when the tech test drives it. I asked him for his best guess what it was. He said it was probably in the clutch safety switch. It was. apparently with vibration you can get a condition where the switch is neither fully on nor fully off this confuses the ignition system and it cuts out.





The solution for me was to override that switch. It is in the clutch handle. If I recall correctly I just shorted across the leads. I suppose any of the safety switches could cause this reaction from the ignition system.



Keep in mind though that with that switch shorted you can start the bike in gear and with the clutch out. perhaps there is a safer way to solve the problem.

 

[thumper]

I had the same problem with my TW. I talked to the tech at my local dealership because it sounded like one of those problems that don't happen when the tech test drives it. I asked him for his best guess what it was. He said it was probably in the clutch safety switch. It was. apparently with vibration you can get a condition where the switch is neither fully on nor fully off this confuses the ignition system and it cuts out.





The solution for me was to override that switch. It is in the clutch handle. If I recall correctly I just shorted across the leads. I suppose any of the safety switches could cause this reaction from the ignition system.



Keep in mind though that with that switch shorted you can start the bike in gear and with the clutch out. perhaps there is a safer way to solve the problem.

we have a winner here! I went out and started my bike and rode it around the block a few times, jumping off curbs and fast take off's and strong braking etc. ran great until I wiggled the CLUTCH SAFETY SWITCH! Bamo! died and coasted to a stop just as before. I think most of us probably ride with at least 1 finger on both the clutch and the brake lever. I may have been bouncing the clutch switch around by doing this.



So thank you, HEYDUKE, I think you solved our problems. Kudo's to you my friend. Ride safe

 

[heyduke]

Glad to help. It's what this forum is all about.

 

[Rainman]

Sounds like the cause, but why would the clutch switch have anything to do with it after the bike is running? You are talking about the little switch thats inside the clutch lever holder on the handle bar right? Isn't the clutch switch only so the starter knows to start it or not? Fill me in if I'm wrong please.

 

[heyduke]

I know it sounds counter intuitive but it is one of those damn electronic glitches. In a past life I was a copier tech and electronics can do some weird things believe me.

 

[thumper]

I know it sounds counter intuitive but it is one of those damn electronic glitches. In a past life I was a copier tech and electronics can do some weird things believe me.

Copy That! (sorry, couldn't resist that one)

 

[Rainman]

Just wanted to update my thread to let you guys know what I found and maybe help someone else who has the same problem.



It turns out that my problem was a loose connection. It wasn't apparent to me until I actually started to unplug and inspect every connector on the bike. Turns out it was the pulser coil wire (#2 in picture).

The problem was where this wire connected to the wire harness under the seat. The connector looks like it had rubbed against the battery and finally wore through and became loose. This is why I my bike would run fine on the street, but would sputter off-road when I hit bumps. The bumps would jar the connector and would interrupt it.



Looks worn from the top:

Upon further inspection, I found the whole connector to be corroded and broken:

I cut off the old connector and crimped and shrink-tubed new connectors on. Problem solved. Bike ran great in my race. The bumps at the race would have certainly jarred the old connector.

 

[jbfla]

Thanks for the update. I'll add checking the electrical connectors to my beginning/end of season checklist.



jb