Is there a joint/clamp hidden by the pegs in the picture in post 336?Thanks. I lucked out because that exhaust was part of the bike when I bought it. I thought this exhaust was sold on Mike's or another online vendor?
Is there a joint/clamp hidden by the pegs in the picture in post 336?Thanks. I lucked out because that exhaust was part of the bike when I bought it. I thought this exhaust was sold on Mike's or another online vendor?
Yes there is. I can take a better picture tomorrow.Is there a joint/clamp hidden by the pegs in the picture in post 336?
Is there a joint/clamp hidden by the pegs in the picture in post 336?
Great stuff right there to file away for future use.I think you need to jet up more. What you have to realize is that the '76-'77 carb set came with the smallest mains (122.5) ever put in any 650 model. They're fine on an all stock machine but are quickly outpaced if you do any modding, and I see you have those Commando mufflers. So, I would recommend going bigger on the mains (127.5, maybe even 130) and if that doesn't fix the popping, you may need one up on the pilots as well. The larger mains may require leaning the needles a step because their bleed-over into the upper midrange will often make it too rich and cause stumbling under heavy throttle applications. If you do that then you will really need a larger pilot because leaning the needle also leans the upper part of the idle circuit. The 3 circuits in your carb overlap a bit, so changing one affects the one next to it .....
View attachment 236986
Just checked my notes. 132.5 mains; 27.5 pilot; needle Center position. Overall runs well. If I ride at low speed or idle too long I sometimes can foul (load) the plugs up. Through all the messing around I did with carbs and jets I’m pretty happy with it the way it is. A short higher speed run cleans up the plugs but now that we’re talking about it I may throw a new set in before springtime.This is what I put into the '76/'77 carbs:
Main jet is 125
Pilot jets - 25
Needle/clip - 4M1-3
I set the air mixture screws at 1.5 turns out from stop
It runs great. I only took it up to about 45 mph as I wasn't near the highway. It seems to have lots of power no issue, but
The engine is burping/backfiring/popping a bit on deceleration from speed when going back to an idle position. I turned the air mixture screws out another 1/4 turn. It might have gotten better but that could be my imagination. Ideas?
I learned the hard way, doing it wrong first... When pilots are to small (in my limited experience) you need to open the butterflies (idle speed adjust) which causes the carb to draw on the needles and the pilots. In my experience ( limited to a sample of one) the idle speed is very touchy at this point. When the pilots are close to correct the idle speed seems to be very adjustable. My bike jetting was wildly off and I started playing mains when playing pilots would have been the "short-cut".Just checked my notes. 132.5 mains; 27.5 pilot; needle Center position. Overall runs well. If I ride at low speed or idle too long I sometimes can foul (load) the plugs up. Through all the messing around I did with carbs and jets I’m pretty happy with it the way it is. A short higher speed run cleans up the plugs but now that we’re talking about it I may throw a new set in before springtime.
I could try that. Will look further into my notes to see if I’d already done that. ThxLeaning your needles a step may fix that plug issue.
Are those stock head pipes with double wall or are they single wall replacements. If they are replacement single wall your exhaust is open up considerably. I had to go 132.5 main, 30 pilots and drop the needle (leaner) one notch to make my tracker run very nicely. If those are new head pipes, you may find they blue quickly with a lean mixture. Heed @5twins and go the rich side first if those pipes are new.
Just checked my notes. 132.5 mains; 27.5 pilot; needle Center position. Overall runs well. If I ride at low speed or idle too long I sometimes can foul (load) the plugs up. Through all the messing around I did with carbs and jets I’m pretty happy with it the way it is. A short higher speed run cleans up the plugs but now that we’re talking about it I may throw a new set in before springtime.