GS550 airbox manifold differences? The 80 is stumbling of idle. Help please

[Guest]

I am working on 2 GS550's. One is a 80 and the other one is a 82. I am having issues with the 80 right now boging down from just of idle to about half throttle. I have ultrasonically cleaned the carbs and checked all the slide diaphrams. There seem to be no pin holes. I have the idle mixture screws set at 3 1/4 because that is where the colortune gave me the best most consistent flame color. What I did notice is the intake boots in the 82 are different. The 82 550's look like this


As you can see, the inner boots are narrowed down while the outside ones look like ones I have seen on other gs's. On the 80 all the boots look like the ones on the outer on the 82. Did I order the wrong intake manifolds on the 80? Should they look like the ones on the 82?

[tom203]

Both the 80 and 82 share the same boots (airbox to carb inlet)apparently with inners different from outers. Not sure why throat size here would cause your issue. I seem to recall that others claim that colortune is sorta useless on cv carbs. 3 1/4 out on idle/air mixture screw sounds far out to me.

[bomber737]

Those who claim the colortune doesnt work are competely wrong. I have used mine on many bikes and they are really the best way to set the mixture screws hands down. It really is the only way to see what color the combustion and allows you to set the idle mixture screw for most consistent and bluest combustion. I though that 3 1/4 was way out but I have been having an issue with my Gs1000 when it transitions from idle to just off idle. It has been very sensitive to throttle position. I enrichened the idle mixture screw to 3 1/2 and not it is not such an abrupt transition, it has made it much easier to control speed in parking lots and at slow speeds in traffic. Bike runs like a top as well. So my plan with the 80 that is stumbling is I will be pulling the carbs and ultrasonically cleaning them. I will be checking the boots for leaks and the condition of the rubber on the vac slides. perhaps I can find a pin hole or something.