Idle sounded like one clogged carb, or miss fire. Not

[Rpmalerba]

When I first got my bike it wouldn't run without the enrichers on. I tried all the cleaners and nothing worked. So I pulled the carbs off ( easy to do ) and took the bowls off and found the large jet clogged on all four carbs. After I cleaned them the bike ran great but had a thumping sound at idle. It wasn't until I heard another GL 1200 which idled smooth and didn't have a thumping sound did I know something was still wrong even though the bike ran great. If I pulled out the screw in the manifold on each carb I found the rpm's dropped each time until I got to the one on the front left. So I knew which carb I thought was clogged on idle. Last night I pulled the carbs again and looked at all the jets, they were still clean and open. Then why does this bike have this thumping sound that sounds like it's skipping? It was not that one cyl wasn't getting fuel at idle, it was that one carb was a hair out of sync at idle and getting to much fuel. While looking at the 4 butter flies I noticed one was just a hair more open than another. The adjusting screw for the linkage was loose and that carb was a hair more open than the one next to it. Once I tweeked it closed the bike went to a smooth idle. Point being if you have a rough idle it may not be that a carb is clogged and not getting gas, but that at idle they are out of sync and one is firing louder due to the extra air and gas coming in. Hope this helps someone as I couldn't find what I was looking for and thought posting this may help someone. Of course they need to be done correct with a gauge, but for now It rides great.
If that's your issue you don't have to remove anything, ( of course I removed everything to get the carbs off ) the adjustment screw is through a hole in the chrome carb cover trim piece that has the clip that holds the two spark plug wires.

[neoracer]

good point

[seabee]

Yep, you can't knock a good carb sync now and then. No pun intended. I just finnished building my gauge sync set with HF gauges that were on sale. I hope to do the sync this weekend.

[Rpmalerba]

Yeah been trying to find a thread about the idle circuit and couldn't. One guy talked about idle air screws so I was holding the carb assy in my hand and spinning it around looking for air screws. I couldn't find any? Just out of fun I was snapping the main linkage when I noticed one buttery fly flap snap fully close but the one next go it have a little air gap? Wow. Who would of thought? Not a lack of fuel, but to much fuel causing the idle to be lumpy sounding.
While 3 carbs had a smooth idle sound, one was at a above idle firing stage giving off that thump thump sound.

[Roleketu]

Yeah been trying to find a thread about the idle circuit and couldn't. One guy talked about idle air screws so I was holding the carb assy in my hand and spinning it around looking for air screws. I couldn't find any? Just out of fun I was snapping the main linkage when I noticed one buttery fly flap snap fully close but the one next go it have a little air gap? Wow. Who would of thought? Not a lack of fuel, but to much fuel causing the idle to be lumpy sounding.
While 3 carbs had a smooth idle sound, one was at a above idle firing stage giving off that thump thump sound.

Where in CT are you? I'm in Springfield, Mass, barely half hour from Hartford. I have a set of CarbTune Pro from England. You are welcome to come to my house an we'll sync your Wing.

[spongebob]

I have a set of CarbTune Pro from England

I'm very interested to know if this is a good kit as quite a few come on UK ebay hardly used, if its worked well for you I will start watching them and see if I can "grab a bargain"..as they say.

[Tropicalsuns]

Carb tune the best IMHO.

[Rpmalerba]

Yeah been trying to find a thread about the idle circuit and couldn't. One guy talked about idle air screws so I was holding the carb assy in my hand and spinning it around looking for air screws. I couldn't find any? Just out of fun I was snapping the main linkage when I noticed one buttery fly flap snap fully close but the one next go it have a little air gap? Wow. Who would of thought? Not a lack of fuel, but to much fuel causing the idle to be lumpy sounding.
While 3 carbs had a smooth idle sound, one was at a above idle firing stage giving off that thump thump sound.

Where in CT are you? I'm in Springfield, Mass, barely half hour from Hartford. I have a set of CarbTune Pro from England. You are welcome to come to my house an we'll sync your Wing.

Hey thanks for the offer. I'm in the New Haven area so your less than 1 1/2hrs. Cool. Hold the offer please and maybe we can hook up soon.

[wingandaprayer]

Carb tune the best IMHO.

+1