Bonneville America Forums Forums Technical Forums General Tech electrical problem, help

I bought a new 07 bonneville america and have been having some problems with it and was hoping someone might have some suggestions. Bear with me as I try to explain the problem. The bike cuts completely off, mainly when it is sitting still at idle and it does not matter how hot the bike is or how long it sits. It has taken as long as 20 minutes to shut off, and then again it has done it right as I pull in to parking space and stop. As you are sitting on the bike, when the bike shuts off, the right side of the motor will be blistering hot, the left side will be cool enough to grab the pipe. I have noticed that when I first crank the bike the exhaust on the right warms at a normal pace, but the left side stays cool, but not every time. I took the bike back to the dealership and they told me the left side ingnitor was probably bad and so they replaced it and I picked it up yesterday. When I left the shop I did my usual check of the exhaust and they felt the same, so figured problem fixed. However, later in the evening, I decided to ride it to work to test it. The temp outside was around 80* so it was nice and cool, not hot. I noticed that when I cranked the bike up that once again the left side exhaust was cold and right side was warming normally. I went ahead and road it to work, but it did not feel the same as it had earlier in the day. When I got to work, approximately 12 miles, I decided to leave the bike idleing to see if it would quit, and I started a stopwatch. After exactly 20.4 minutes, it quit. I then took a tempature reading 4 inches from the jugs on the header pipe, the right bank pipe had bronzed and checked 220*F, the left side checked 116*F and I could even grab the pipe in my hand without having to let go. The bike would not crank back up until I let it sit for about 10 minutes. About 8hrs later I cranked it up to ride it home, and once again checked the exhaust and this time both sides were firing the same. It ran like it had earlier yesterday when I picked it up from the shop. When I got to my house and pulled in to the parking spot I put the bike in neutral while it was still running and put the kickstand down so I could get off and check the temp on exhaust while it was still running, but, before I could get my gloves off the bike quit. So, that blows the whole theory of the bike being hot and doing it, especially since it was probably about 65*F this morning when it happened and the bike was clearly not overheated. Now enters my main concern, which is, what kind of damage is being created internally on the motor by this. I have discussed this concern with a friend of mine who is also a Hall Of Fame engine builder, and he agrees that there could be some internal damage created by it that may show up a month from now, or maybe a year or so from now even if the problem is fixed. At this point should I be pushing for a new motor as well? I really like the bike and was hoping someone here may know something that could help. Well, there it is, any thoughts at all?!?

Jon

Definitely sounds like the left's only firing intermittently. The easist way to test it is to pull the cap off the left hand spark plug while the bike's off, put a spare spark plug into the cap (pretty much any plug's fine) and ground the body of the plug to the engine either by sitting the plug firmly on the block or use a jumper lead from the plug to the bike's frame. Start the bike and watch for a spark. Then turn the bike off and swap to the right side. You can do the same thing by pulling the cap of the plug while it's running and listening for changes to the idle, but that's asking to get electrocuted.

What concerns me more is that the bike's cutting out - technically it should keep on running even on one jug. I wouldn't let my bike (or any air-cooled engine) idle for 20 minutes even when it was running fine, and with it only running on one pot you stand a good chance of overheating the engine so much that the rings will de-tension. Check this with a compression gauge on both cylinders - they should have the same pressure give or take about 5%. The only other damage I can think that it'd cause would be premature wear of the main & big end bearings from the uneven firing but unless the problem continues for months you'll have sold the bike long before that shows up.

Other possible reasons for it to die intermittently and refuse to restart are a blocked fuel vent pipe (often happens when removing/replacing the tank) or a partially blocked carburettor vent pipe. To diagnose the fuel one wait till it dies and remove the fuel cap. If the pipe's blocked/squashed the cap'll be hard to move and there'll be a sucking sound as it loosens, then the bike'll immediately restart. The carb vent pipe is one of the open rubber hoses that vents to atmosphere below the bike near the battery. It can become partially blocked by mud/dirt and can cause the problem you describe (the dieing for no reason problem, not the running on one side problem )

It's a brand new bike - take it back to the dealers and tell them you don't want it back till the problem is fixed!

Thanks for the response. The only reason I let the bike idle for 20 minutes, is because I got caught in traffic one day for 20 minutes when it quit on me which is when I first realized I had a major problem, so I was trying to re-create that situation. It would be better to monitor the temp. on both cylinders as it is running, but since it does not happen all of the time, it is hard to do. I will check the vent tube just for the sake of knowing I did, but, I would have to imagine the shop checked for that when they had it. Keep in mind, this bike only has 450 miles on it, so it is truly not the correct way to break in a new motor. I plan on taking it back to the shop on Tuesday, they are closed on Monday, and I just want to be able to gvie as much information as I can about the symptoms in hopes of finding and resolving the problem. Thanks again for the response.

Jon

You might want to consider the floats sticking also....main ingredients for combustion...compression (should be fine), spark (questionalble but tried, due to replacement of Ign Module) and fuel. No fuel would give this symptom, clogged vent would affect both cylinders. My $.02

later, Tom.

Makes me wonder if they also checked the coils. Coils often become heat and running time sensitive before failing completely. It could also be something as simple as a bit of corrosion from moisture getting into the wire connections.