If the bike is not fully warmed up....then it is normal.  If the hesitation goes away when the bike is fully warmed up - then don't worry about it.

Carbs are not able to make constant adjustments to the mixture like fuel injection and computer systems can.  The choke is designed to work when the engine is cold - while the carb is jetted to run when the engine is warm.....the time between those two extremes can result in some stumbles or flat spots.  When the engine is not fully warmed up some fuel can condense on the intake manifold and drop out of the flow....and the fuel mixture does drop a down a bit into the lean side for a couple of seconds whenever you open up the throttle - the combination of these 2 issues cause a flat spot for that first mile or two until the engine is fully warmed up.  If the stumble continues once the engine is warm - you need to raise the needle about the thickness of 1 washer (go to 2 washers if you currently have 3 in place of the white spacer).

If your engine doesn't do this when it is cold....it most likely is jetted too rich for proper running when it is fully warmed up.

Are you using the choke when it stumbles?

Don't spend time warming the bike up sitting still.....it warms up just fine while riding away calmly.  Don't do any full throttle or high rpm riding for a mile or two.....the clutch can slip while the oil between the plates is still cold and thick, and the clearances in the engine aren't yet normal when some parts are warm and other parts are still cold.

I get my gear on, sit on the bike and turn on the petcock, pull up the sidestand, click on the choke, turn on the key, and start the bike.  Within about 10 seconds my choke is pulled off, and I just idle the bike at around 2,000 rpm until my GPS speedo has locked in to a signal....maybe 30 -60 seconds.  Then I pull in the clutch, click it into gear, and slowly ride away.  Not only does it allow the bike to warm up a bit - my neighbors appreciate the fact that I am not speeding past their houses!

Dave wrote on 10/28/15 at 03:51:52:


My next door neighbor loves the bike. The Harley "Loud pipes save lives" guy across the street won't even give me the time of day. And the other guy across the street is smug about why I should have another project, not something he would do, gives his advice (nobody asked!) and goes back to his perfect world.

I never tear out of the driveway. The road is pretty residential and I have no need to do it anyway. So Dave, no wheelies?
Jeff