Carb question 1150

[renobruce]

God, I love this site!! You folks are great!! I have some more dumb questions. First, some history..... '85 GS1150, 3,700 miles, stored (properly) ~15 years, originally parked for bad reg/rec. Upon puting in new plugs, I noticed the old plugs look perfect..... uniformly light brown.
I took the carbs off for cleaning. They weren't all that bad. I left them together on the rack. I followed the instructions in the Clean-up Series (very helful). But, I did not remove the air screws. They are still capped from the factory. I didn't adjust anything. Back on the bike. Fired right up. Choke works great. Fires after sitting a couple hours without using the choke. Runs good through all RPM's (I think). A little too much vibration, though. Idles pretty good. I checked the synch on the carbs. #1 is highest, then they drop down 2, 3, 4... like a stair step. I pulled the plugs. #1 looks good, then they get blacker progressively down the line. #4 is the worst, coated with dry, black carbon.

Here's the stupid questions. Is just synching the carbs going to correct the carbon build-up problem? Should I have un-capped and cleaned those air screws? And if I do need to clean the air screws, can I do it without taking the carbs off the bike? I was just going to synch them and find out for myself, but found out I can't get to the center adjuster without the special tool. So in the meantime, any thoughts?

[Anonymous]

The air screws adjust the amount of air that mixes with the pilot jet and primarily affects only idle on your bike. The vibration and uneven burn on the plugs indicate a sync issue. Get a manometer on the bike; especially if your plugs burned the proper color previously. When cleaning your carbs, I hope you didn't pinch any of the diaphragms when you lifted the tops. Holes in the diaphragms make carb sync a definite waste of time.

[renobruce]

I did put a manometer on it. The synch is off, as I indicated. The big thing was if synching would help, and you answered that. THANKS!! I didn't want to have to pull those carbs off again :?

[renobruce]

The air screws adjust the amount of air that mixes with the pilot jet and primarily affects only idle on your bike. The vibration and uneven burn on the plugs indicate a sync issue. Get a manometer on the bike; especially if your plugs burned the proper color previously. When cleaning your carbs, I hope you didn't pinch any of the diaphragms when you lifted the tops. Holes in the diaphragms make carb sync a definite waste of time.

Hey, wiredgeorge. Considering I only cleaned and didn't adjust anything on the carbs, and left them together,why are they now needing to be synched?

[KEITH KRAUSE]

Carbs loose their synch. They need to be maintained like anything else.
Also, the screws you're talking about are called mixture screws. As part of the pilot circuit, they regulate a second passage to the carb throat. They regulate the amount of MIXTURE, not just air or fuel. They will effect your jetting up to 1/4 throttle. They have an overlap effect with the jet-needle.
You should synch the carbs before playing with the jetting.

[renobruce]

Hey, y'all, just a follow-up. I got the carbs synched today. It went well. They now stay in synch at idle, 1,750 rpm and 3500 rpm. The carbon build-up problem is gone. And my hands don't tingle anymore 8) All the vibration problems are gone. Much more and smoother power. What a difference a good synch will do Thanks for all your advice. Time to go out and rool over the 4,000 mile mark

Bruce

[KEITH KRAUSE]

Glad she's running good! Having the carbs in synch is very important.
A lot of people waste their time troubleshooting things when all it needs is a good synch. I think a lot of people figure it's too technical or something to synch carbs, so they don't try to learn.