I've been chasing this since I bought the bike. The bog came when you throttled on, after closing the throttle. I had been working on the basis it was a lean condition (the butterfly opening).
Last night I played with the needle position. Taking the needle down one position to the third clip (making it richer) made the situation worse. Taking the needle to the first clip was too far. I finally fixed it by replacing the 2.66 needle jet with a 2.64. I reset the mixture screws out to 1 & 1/2 turns out. Test rode it last night, but couldn't be sure I'd cracked it because it was so cold (dense air). But today the bike was the best I've had it.
I also has a go at improving the rear brake, by deglazing the drum & the shoes, repositioning the drum brake lever slightly to a 90 degree angle at actuation, & raising the brake lever to it maximum height (so I could get a better stomp on it). I filled the brake inspection ports with silicon (in the absence of the proper plastic fittings, and filled the centre of the wheel with a modified hanger off a broom, so that today stream crossings didn't fill the drum with crap. Whilst all this had an immediate impact, by the end of today the bike was back to square one. Next steps new shoes, & to reposition the cable pull on the brake lever.
Finally I've replaced the inside paralever pivot. The old one was worn, which killed the pivot bearings. I see that my new bearing are also on their way out, so will need a new set there too.
Maybe should have replaced these as a set, but unfortunately when I replaced the bearing last time I hadn't realised the pivot would also be toast.
Sunrise from my kitchen window this am
Today Matt, EddieB, Tony, Mark & I headed over to Wairarapa, initially to Tui's (formerly Toppy's) for coffee, then into the Aorangi Forest Park to Sutherlands Hutt.
Come one Guys, was it something I said??
Two of us made it to the top of Cnut Hill. I'll give you some hints. It wasn't me, Tony, or this character, who needed to make repairs to the mighty DR. I'm sure he'll post embarrassing stream crossing video in retaliation...
Congrats to Matt & Mark. That hill is a hell of a knarly...Steep & lots of erosion ruts, loose rocks etc