Join Date: Sep 2004
Location: Medford, County of Jackson, Oregon, USA
Model: None at present
Hi Joe, thethings on your list that won't cause your problem are the timing belts and a dirty air or fuel filter, and carb balance.
Usually hesitation like you describe is caused by either a too lean condition caused by the carbs or a problem with the timing advance. A dirtyair or fuelfilter would cause increasing problems as the rpms increase, they wouldn't get better at higher revs. Carb balancing won't help with this one, it will make the bike idle smooth and pick up better from idle but that's about it. A vacuum leak should affect the engine at lower rpms but it could possibly cause problems with the ignition timing advance. One possible electrical problem could be the gear position switch. If memory serves the ignition timing is partially controlled in the top two gears by this switch.
I'd pick on the carbs first, possible accelerator pump or dirty jets. You might try running some carburetor cleaner with the gas to see if that will help at all before you start having any mechanical work done. The next thing I'd take a look at would be the spark plugs to make sure they aren't marginal. Try putting on a little choke and see if the problem gets better or worse, if a bit of choke helps it's likely the carbs are the culprits and need a good cleaning.
None at present
Past 'Wings: GL1100, GL1200, GL1500, GL1800
Current BMW C650GT