Bizarre, funky issue when rolling up to a stoplight

[1948man]

To try something cheap and easy, leave the choke partially on for a while longer (experiment). Might not help but won't hurt anything. Does this symptom go away if you ride the bike for a significant amount of time and get it well warmed-up? I have bikes that will die on decel if I start riding too soon after startup with premature cancel of the choke.

I had that same thing happen to my bike, I fixed it by fixing all the little air leaks I had. Normally the air leak would be because of an intake boot O-ring, but in my case all I did was get a new foam air filter and put new weather stripping on the filter and on the air filter side covers. That fixed my issue. I also put some Seafoam in and when I started up I had to initially adjust to idle screw because it was so messed up from the way it was running before. Once I got the idle screw adjusted properly the bike was idling perfectly even after being completely warmed up. I'm not sure if this will help with your issue, it could be a number of things from air leaks to the carbs needing tuned. Good luck!

This is true. I live somewhat in the boonies and have found a a bike mechanic somewhat close-by, as I am not comfortable with valve adjustments or taking apart the carb jets, etc, so am just clicking my heels hoping its a simpler issue. Wishful thinking I suppose but I have put those things off.

I went through your other posts, and I did not see that you have actually checked the valve clearances, cleaned the carbs or done a carb synchronization.

A combination of those three maintenance items should get you closer to where the bike needs to be in order to avoid the stated problem.

[BigD_83]

I went through your other posts, and I did not see that you have actually checked the valve clearances, cleaned the carbs or done a carb synchronization.

A combination of those three maintenance items should get you closer to where the bike needs to be in order to avoid the stated problem.

Hey folks,
I got a 1979 550E and while it's a blast and I love the bike there are a few quirks it has relating to the idle

it cold starts absolutely fine, first crank or first kick and holds a nice idle with the choke on, and after riding it or a bit (like going into a store and coming back, it starts fine with the choke closed)

but after I get partway down the road pulling out of my driveway and flip the choke off the first time, the next time I coast with the clutch in or stop, the bike slowly dies, as in the idle is too low, unless I quickly crank the idle screw a few turns til it gets back up to a stable idle

THEN, when I get a few hundred feet til the next stoplight, about 75% of the time when I downshift, roll off the throttle and coast to the stop, the RPM climbs up to about 3000RPM until I move the idle adjust screw about a half turn or so, then it goes back down to a stable idle, until the next time I decelerate to a stoplight. It feels like it happens more when I come to a stop quite fast and brake quickly and abruptly.

Once the bike is moving there are zero issues, no backfiring, no hesitation or loss of power when I crank the throttle, it's just when slowing to a stop.


I'm by no means experienced in mechanics or carburetors so bear with me here

Thanks,
Mason