bs34s and slight idle blubber

[CDNTX650]

Greetings. Bike is my 74 with 34s. 137.5 mains , shimmed needles, 45 pilots. uni filters and brit mufflers. Bike is quick. Fueling is good...idle is at about 1100. right side just humms right along. Left does pretty good too. But has the occasional little blubber. just went through and cleaned em. Even switched the mix scews and orings around. Still the same. Have the screws set at 3.5 turns out. Pamco....plugs over pilot jets....new shaft seals. Fuel filter. Really not sure what to try now. This little irritation is only an idle problem.

 

[ippytattoo]

Quick fix, Don't let it idle! Just kidding, you may need to go through and check the carb sync with a manometer and mix screw settings using the dead cylinder method but when I had the BS34's on mine I also had a little occasional stutter but my idle was closer to 900. It would sometimes stutter enough to stall out.

 

[CDNTX650]

Sync was good. It does seem to do it less when ambient temps are warmer.

 

[CDNTX650]

Made progress....reset lash. Wider than i remember setting it....sync was easier to get on now. Still does it a tiny bit. have to have your ear right up to the exhaust on the left side. Plugs are nice. Think ill live with that!

 

[5twins]

Mine has always had a little miss or sputter on the left cylinder at idle. This has been with points, now with a Pamco, and with 3 different carb sets I've tried. I don't know what causes it, nature of the beast maybe.

 

[CDNTX650]

Good to know 5t!

 

[CDNTX650]

Hey 5t. the signs of worn choke pads should be uber rich correct? I dont have that problem. Just wanted to rule it out. Choke does work and will kill the bike when warm.

 

[5twins]

Yes, you would run rich. Worn chokes aren't a common problem but do happen occasionally. Like I said, I don't know what the cause is. I'll have to give a close listen to some of the other 650s in my area to see if they exhibit the symptom as well.

 

[CDNTX650]

Thanks. I havent seen worn ones yet either.