Low Speed Surging…

[AAAltered]

R5 runs great overall.   For some time I've meant to catch this one issue on video but I've never gotten around to it.

At low speed, (little/no throttle) or while slowing down on local type roads the bike has a very distinct surge, like a wha-wha-wha-wha with some appropriate jerking.  It smooths out with a little throttle.

I assume this is too small/large of a pilot jet? 

I rebuilt with 100% new Mikuni brass last winter and my invoice shows 35 pilots now.  The mains are nicely dialed in via chops.

Thoughts?

[Striker1423]

adjust your air screws and re-test.

[Czakky]

My R5 did that. I was able to mostly solve with air screws.

[m in sc]

yup.

old school way of doing pilot air screws:

warm bike up. like ride it a short bit and come back to garage. keep running. usually a fan in front of the motor is a good idea. let idle. get off bike, and just crack throttle up to 1/16th to 1/8th and hold it. if it rises and climbs, its too lean. if it burbles and goes back to idle speed or sounds.. heavy... too rich. adjust in 1/4 increments. repeat. then try 1/4 throttle. it should hold an rpm at a given throttle position.  I'm guessing you're a bit rich on the pilot air screw setting.   

[pidjones]

So, rich on pilot air indicates need for clockwise on screw? Mine started doing this yesterday (hadn't done it before). Seems no big deal to carry a screwdriver in my pocket and try adjustments to improve.

[Striker1423]

Turning the air screw in richens the mixture, turning it out leans it. That simple.

[m in sc]

yup. in = less air or richer.  also why you don't want to go under 1 turn total, will affect velocity and fuel atomization.

good rule of thumb for carbs, typically, is that if the screw is on the air filter side of the carb slide: air screw. on the motor side: fuel screw.