Motorcycle Forum banner

1 - 2 of 2 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
I have a 2008 Bonneville T100 (Carbureted).

Recently after riding for a while, I will come to a stop and try to go again. When giving it wide-open throttle, it will bog down really hard for about 30 seconds and only go about 5 MPH. It will also backfire at times. Then after about 30 seconds, it will suddenly go back to normal and I'm off. It only occurs after full stop, doesn't happen at every stop, and only occurs after it warms up and has been riding for a while.

Yesterday I rode about 250 miles from 5,000 feet up to 12,000 feet. It happened at all elevations randomly. I filled up my gas tank multiple times.

Since I'm at such a high elevation and it doesn't present itself when warming up / idling or every time I give it throttle, I'm tempted to rule out clogged carb components or incorrect jetting sizes due to over-leaning. I'm willing to hear a good argument on the contrary though (and by "good argument" I mean more than the fuel system equivalent of level 1 tech support: "Did you turn your computer off and on again?")

My next thought is vacuum leak, but I don't have as much experience with this issue yet and how it could be intermittent and why only after warming up.

Thanks for your thoughts and help! I'd love to get this Bonnie running right again, and stay out of the middle of intersections :smile:
 

·
Premium Member
Joined
·
5,274 Posts
It could be too rich for the altitude, because you need a leaner mixture for the thinner air. Have a look at a spark plug; it should be light gray to white near the tip of the insulator. You can try taking the air filter off; that will lean the mixture quite a bit, and, if it runs better, you have your answer. One would think your dealer would jet it for your altitude, assuming you bought it from a mile-high dealer. 'Back in the day', there were little shops around Pike's Peak that would jet a car's carb for the altitude, then put it back before you left; that all ended with computer-regulated and altitude-compensated carbs, and fuel injection, of course.
 
1 - 2 of 2 Posts
Top