Bonneville America Forums Forums Technical Forums General Tech Cold Start Problems with 2008 America

I've run into a perplexing problem with cold starts of my 2008 Bonneville America and could use some ideas before I take it to dealer. I live in S. Florida, so very cold weather isn't a problem. In the fall I only needed to pull the choke out for the first one or two cranks; it won't run continuously with the choke fully out. Since the weather has gotten chillier at night - about 40-50 degrees, I have experienced really bad starting performance. I can get it started with the choke out, then close it and it often dies. Then I can get it to start with the choke closed but it will quit after a few seconds, Or it will idle roughly and then when I twist the throttle slightly it seems to bog down and the engine will die. If I can get it to run long enough to get warm, it seems to start running OK. Could it be a problem with the air injector system? How can i troubleshoot this problem?

Perplexing, yes

I live in the UK and haven't had the problems you describe, and I guess its slightly colder here than S. Florida

If I leave the choke fully out, she just revs to buggery, same with half out, just less so
If I close the choke too soon, thats when she cuts out, and wont restart without the choke

Its possible a re-map from the dealer will sort your problem out, but take more notice from others here because my mechanical ineptitude knows no bounds

PS. The only starting problem I have is when the battery has been drained by the alarm

Assuming you have a carbed model of the 08 America. When it is cold, you need to pull the choke (enrichener) out all the way. Start the bike then tap the choke in a bit to keep the bike running at a reasonable idle speed. If needed, leave the choke out with the bike idling higher than normal until the bike warms up. That is how I start and run my ride when it is cold. The bike needs a lot more fuel when it is cold to keep running. Since your bike runs poorly when cold and fine when it is warm, it appears your choke needs to be left out.

Have you modified the bike at all?

Sorry, mines an 08 EFI and I forgot we got them earlier than the states

Maybe vacuum caps cracked, or manifold rubbers loose. Still stock? Smell gas when trying to start it?

I had a similar problem with mine. While it was still all stock it would start up and then about 2 minutes down the road it would feel like it was bogging down and would stall out. Then I would try to restart it and it would just crank. I would loosen the gas cap and it would usually restart then. I finally made a few mods on mine and it has been fine since. My diagnosis was the very restrictive air fuel mixture the factory has to set to pass emission standards. I'd try opening the choke like Gregger said and let her run for a little bit if you're still running all stock.

Is your Idle adjuster set right.