Bonneville America Forums Forums Technical Forums General Tech Could it be another problem?

Was on the way to work and my America lost half its power. Pulled over and it died. It was restarted and ran like a champ for about 5 miles and it acted up again. Made it to a gas station and filled the tank and rode another 35 miles without problems. I suspect trash in the tank or fuel line. Could it be anything else?

Tank vent obstruction? Happens again, try loosening the gas cap and see if the prob. goes away.

It makes sense that by filling your tank, the prob. would go away, as a full tank eliminates most of the air in the tank, I suspect that when your fuel level goes down and there is more + air than -fuel, your situation will return. Pull the tank and check the vent hose.

Thanks guys. Now I have to find a new place for service. Sadly, the shop I was using closed.

3 Bolts on the console, lose the seat and the tank pulls with one bolt?

What should I look for in the vent hose? Clogged? Deterioration?

Have you had the tank off recently? The vent hose comes out under the tank just to the right of the console (if your sitting on the bike) in as about a 45 degree angle down to the front of the tank then sweeps back towards the back of your bike, the part that hooks up to the tank is very close to the spine of the bike and sometimes when people put them back on it gets crushed a bit on the spine, or sometimes its put on inverted with the 45 degree bend upwards etc. if you take a flashlight and look up under the tank (in the front on the right side) you can see it, if its bent or on the spine you might be able to tell, otherwise as noted, three bolts on the console, one bolt on the tank (under seat ) and off she comes.

I haven't taken the tank off (I'm dangerous with tools ) The bike has 57k miles and has never acted this way. Should I still check the hose?

When it starts acting up, loosen the gas cap.

Do what Ryk said loosen the gas cap and go for a ride, if the problem persist then it's not the vent tube and no point in taking your tank off, yet.

Try the experiment and get back with us.

Well drats! Even with the gas cap loosened, it acted up twice on the way home. Once for about 15 miles then again for about a mile. The second time it occured, the bike sounded like it farted twice then it cleared up. The remaining 35 miles home were fine. As a matter of fact, about 15 miles from home the gas cap was tightened (not until it clicked) with no ill effect. Perhaps I'll take the tank of tomorrow and check the vent hose.

I'm thinking electrical now that you have confirmed it isn't a vacuum problem. When the bike looses power, does it sound like it is running on one cylinder. The next time it happens and you can pull over, try to keep the engine running and determine which cylinder is firing (one pipe will cool). If that happens, check the coil wires, 2 small primary wires and the plug wire for fastness. Given the fact that you are removing the tank, checking these wires (under the tank) becomes easy.

If you notice one cylinder misfiring at times and it is always the same cylinder and your wiring is tight and not corroded, you then have to determine if the problem is a coil or the CDI unit. We'll get to that once you confirm it is running on one cylinder when it looses power.

Oh, I'm assuming you have a carbed model.

Good luck

Its a carb. The bike acts like my old dirt bike when the air filter was clogged with debris. It doesn't sound like its running on one cylinder but I'll test it tomorrow.

I doubt it is a clogged air since the problem comes and goes. You have two carbs on the unit. One carb failing intermittently doesn't normally happen. Pull the plugs and note what colour they are and if they are the same.

I could see a partially plugged fuel filter blocking the flow after a few miles starving the engine but it shouldn't unclog itself also although it doesn't hurt to check. A quick check for fuel flow is to open the drain cocks at the bottom of each float boal and see if there is a good flow of fuel. That will eliminate the fuel filter.

Have you done any mods to the bike?

No mods. Just rejetted when Specialty Spares were installed 4 years ago.

57,000 on the bike with no mods, good chance the hidden filter is clogged.

Seeing that yesterday was Father's Day, I didn't have a chance to work on the bike. Will keep you folks posted.

Tracked down the guy who owned the shop that did the service on my bike. He recently replaced a coil on his bonneville that was having similar problems. I'll let you folks know what the diagnosis is once the bike is fixed. Hopefully it won't be costly.

Good news! The shop just called and it's not the coil or cdi. It was water in the tank. I guess this can be added to the list of things that act like a faulty coil or cdi.