Bonneville America Forums Forums Technical Forums General Tech Looking for ideas

On my 06 Bonneville:

It misses pretty bad, usually after running for 2 hours or so but has done it from startup a time or two. The miss occurs at constant throttle, or very slight throttle pressure at speeds from 30 mph up to 80. Seems to run w/o miss at WOT and at idle. Does this with or without the TPS connected.

During the AR rally had the coil replaced, ignition wires and plugs check good. Later I checked the gap on the pickup coil (it was off a bit but didn't fix the miss when adjusted). Replaced the igniter (Dang, with the procom when is it not missing it runs like a scalded dog as they say down south of here). Have been through the wiring and found no loose or shorted connections but am going back through with a fine tooth comb. When it first started I opened the pilot jet a 1/4 turn since it should have the most influence at a small throttle opening. Have not been into the carbs since have not seen a connection but am open to most anything if any of you have ideas.

Thanks
Troy

How many miles on the bike & the plugs?

Plugs can fail internally, & intermittently.

7k on the bike and maybe 500 on the plugs. Seems to fail on both cylinders so didn't think both plugs would have intermittent failure. If going through the wiring again doesn't yield a fix then am considering replacing the pickup coil. Have heard that they have sometimes failed but usually just quits running then the coil fails.

I wonder what has been done with the carbs. I've got a spare set of carbs for my bike that I tried to use recently and I didn't clean them before installing them and they had been on the shelf for about a year since their last use. The result was about what you've described with yours. Idle great, blubbering through the mid-range but seemed to catch up at wide open. I was thinking something to do with the needles/slides or else mains are clogged. That's not to say that yours is the same problem... could be other things but you've changed coils and there's not enough miles on your plugs or wires unless you've just got a bad set. If your original CDI is good and replacing it didn't fix the problem, put it back on and make sure the carbs and clean, adjusted, balanced and that the slides are opening. My slides got stuck wide open one time after I had been "working" on mine and seems like I had a mid-range problem then too. So, go for the simple things first. Usually pickup coils either work or they don't. Same with ignition coils and CDI modules. I know, there are exceptions to every rule when it come to this stuff. My suggestion is that since your ignition system tweaks have yielded no positive results, the problem must be elsewhere. So, check your carbs. A mouse built a nest in my air cleaner one time that caused similar results. Idle good, blubbery mid-range, but once past the mid-range it would pull on out. Go figure, Good luck!!!

Thanks for the suggestions. Went through the carbs last spring but have it on my list to check them out again. When I first got the bike it had some trash in the fuel line that stuck a float open so at that time I cleaned everything that touched the fuel but time has passed. I have an old one eyed cat that hangs around and probably brings me an average of 20 mice or rats a month and has done so for 5 years so i can probably discount that problem. He has to hunt in a field a couple of blocks away since he cleaned out the neighboring lots/land.

06 Bonneville as in single coil, 360 motor?

Yes. Have owned an America as well. Not a lot of difference in most systems.

Ok. Appears to have been the pickup sensor. The engine gradually faded away until there wasn't enough spark to kill a fly or start the bike. Replaced the pickup sensor and away she goes. FINALLY!!! Has been a most frustrating experience.

Good to know, congrats!

Yes good to know,can you stick that in the vault Troy?

After going through the wiring for the second time and tearing the carbs down (clean as a whistle) it was about all that was left to try. Not sure how to diagnose this particular problem other than to eliminate each potential problem until there is only one left. Maybe with an old oscilloscope you could see an oddity in the firing but I haven't seen one in a garage in several years. Maybe I just haven't looked in the right places since I know they are still on the market.

I learned on one of those computers when I was in school. Great piece of equipment.