TOPIC:

Ok, just to re-iterate where this project is:

Bike was purchased off FB from Scott in Kansas. Engine was disassembled. Scott said cylinder 3 was not running, but otherwise bike was ok.

I’ve have:
- put in big bore kit
- replaced worn items as needed
- manual cam tensioner
- hyd clutch
- installed DG 6-1

Scott said the carbs had been sent out for service while the bike was apart. That was evedent because the bowl gaskets where new. However, outside was dirty so I cleaned all with degreaser, soap and water and tooth brush. Sprayed passages with brake cleaner and all seemed clear and clean.

Bike is together. With the throttle all the way closed - butterflies closed and NOT on the idle or choke stops. So, COMPLETELY closed. I verified this with a bore scope.

Engine starts ok with choke off (it should not). Idles fast (1100-1500) cold and way fast (2500-3000) hot. Revs off idle fine. Appears to be idling in all 6 - but not verified.

Don’t know much about these carbs but it seems the air must be getting in via the idle or coast circuits.

What I think are the idle air adjustments are still plugged. I will try and post a pic.

Suggestions?

There is currently no air cleaner on the bike.

You may want to read Scotch's article about carb rebuilding on this site and/or PM him about the problem for his thoughts on it or about purchasing his carb cleaning tools he also sells brass floats as well.

I went and read a number of the old threads, including Scotch's rebuild stuff. It's definitely not carbs being out of sync, or anything related to fast idle adjustment. The butterflies are fully closed and they are not sitting on either of the idle adjustments.

It sure seems like it would have to be an assembly issue since all 6 cylinder seem to be the problem. No idea who worked on these carbs.... I'll bet it was not Scotch!.

I'm going to check the plugs to verify all are similar (expecting rich, but not horribly). Then I will pull one of the choke plungers and one of the coast diaphragms to see if all looks OK.

Don’t know much about these carbs but it seems the air must be getting in via the idle or coast circuits.

A quick guess would point to this, as if extra fuel is added to the mix extra air would make the rpm's go way up.

I'd check the clearance between the 'roller' on the throttle assembly on the carb and the shape on the choke shaft that activates the butterflies with it's curve. I don't know how better to describe this. In off position they should be a gap between them. Too tight - makes butterflies open too much from start, regardless other adjustments and synch. You mentioned the butterflies are closed with choke all the way up when starting and idling?

You can't discover some faults unless under a microscope, and it makes all the difference. Replacing those idle jets with brand new Mikuni proper I for example decided to implement religiously. If not anything else, it creates a great secure starting point. Just the wrong atomization there can mimic other problems. Scotch was ready to render my carbs a scrap when we collaborated on putting them back to life. They ran awful. Then with all the idle jets replaced - magic happened! Ran smooth and problem solved. An Eureka moment. I'd say check that adjusting screw and replace if that doesn't work the jets.

I guess I don't need to mention adjusting the floats to correct level. That's the starting point. If not done right all else will be shits.