Carbs and valves 79 GS1000L

[Rodman]

I need to rebuild the carbs and do a valve adjustment. The carbs seem a daunting task and I have read so many posts where those have failed, more so than those of success but i'm not scared. Should I do the valves first, make sure all is well and then the carbs or both at the same time?

[mrl1000l]

Valves first because they regulate the amount of air/fuel the cylinder receives. The standard service manual is pretty good method on how to bench synch them. So after they are clean, you can bench sync to get the bike started. Then vacuum sync if you have that available to you. Then set fast idle with air mixture screws. Then plug chop to make sure you are doing it right.

The biggest danger in cleaning is the idle mixture screw underneath the carb body and in-between the float bowl and the motor is very fine tipped. If you over tighten it, you'll surely break the tip off. Turn those in extremely slowly, counting each turn as you go.

Bass cliff has a cleaning manual for these carbs.

[Steve]

Give us some approximate geographical coordinates, one of us might be close enough to give you a hand.

.

[Rodman]

Okay valves 1st it is. I am in Denver CO. I bought ALL the things needed to do both the valve adjustment (minus shims, who knows and our shim club guy is local for me, WHOA!! ) and the carbs (have Basscliff manual too), down to the JIS drivers, even have a Morgan carbtune (never used) and the colortune. The intake boots seem "soft" to me but I'm not opposed to getting new ones if required. Please advise.

[mrl1000l]

Pictures will help folks on here assess the carb boot condition. Soft sounds good. You should also check that the o-rings behind the boots aren't hard and flat. They most likely are if they are original. You can get new ones cheap and fast from (http://www.cycleorings.com/intake.html).

I never did get a good ear for setting the fast idle with the air screws, so I got a Colortune as well. Colortune was extremely helpful on getting my air screws dialed in.

I personally found that bench syncing my carbs was much more accurate than vacuum sync for this bike. The vacuum sync at 4k rpm is pretty close when the bench sync was right. My local vintage MC tuner told me that taking the top caps off to make adjustments to the vacuum sync at idle is problematic. This is because at idle the slides are mostly closed, a strong engine vacuum will tend to pull air in past the slides from the top opening throwing off the manometer. This is less of a problem at 4k rpm because the slides are up and the engine vacuum will pull air through the carb intake and not the top because it becomes the path of least resistance. So it seems like if you want to make adjustment to the sync with the bike running and the manometer connected, set your idle for 4k rpm.

If I've totally botched this, I'm sure someone will come along to help, but that's been my experience.