RGS running rich

murphus

murphus

Senior member
Location
Lost in the Midwest
Looking for thoughts on what would make my RGS run rich after a thorough carb overhaul. All jets replaced except for the non-return for the accelerator pump. New jets are all to stock specs, whereas it had been jetted extremely rich, with 145 mains and 68 slow speed. Now running 108 mains and 55 slow speed. Only thing that comes to mind is perhaps the choke pistons aren't seating? They're new, and I think I set the cables so they're loose, i.e., no tension. Just pulled the plugs in anticipation of cylinder head retorque and checking valve lash and the plugs are all evenly black and sooty. I hadn't done any sort of quick start. Rode it back from work the other day and shut it off hot after a 30-mile ride.
Richard
 
how did it run? at least it is the same for all cylinders, checking the choke plungers is a good idea, I would put fresh plugs in it, and take it for a ride, weak spark could be another thing to look for
 
Richard,

that can be caused by several things:

-float valves not closing and carbs overflowing
-float levels to high
-Needle in wrong position
-Chokes not seating
-a sealing O-Ring missing somewhere

check the chokes first and then float level and float valves
 
Think I have it sorted. Pulled the carbs, rechecked the floats, they were high/too much fuel. Reset using the credit card tool method (which I hadn't done prior -- definitely more accurate than freehand), calibrated the accelerator pumps (they were definitely pushing too much fuel), and set the fuel/air screws to 1 turn. Runs spectacularly. Clean, crisp throttle response from all points, perhaps the slightest burble on occasion in mid-transition, but no hunting or surging, just nice clean carburation. The fuel/air screw setting is curious to me in that the carbs previously had 68 slow speed jets and now have 55s. However, it also had the U.S.-spec fuel/air mixture screws, which have a substantially longer taper, which I assume was used to limit how rich the carbs could be set. Regardless, nice to finally have it back on the road. My 30-mile ride into work this morning in a cool fog (which I'm sure helps how it runs) was glorious. The pic shows the U.S. needle at top, standard (old needle from the SF, not the new ones I put into the RGS) at the bottom.
Richard
 

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Interesting. The info I had came from Wolfgang, who specifically asked if I had the long fuel/air screws when I was ordering parts and suggested the shorter type. And he might have said early/late and not U.S.-type, I might have inferred that.
Richard
 
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