Richard, you are a genius! When I think of all the grief that stupid diffuser gave us over the years..... I never thought of pitching it. What a simple solution. I love it.

Thanks Martin, more frustration than genius I think. The main problem seems to be junk in the fuel that the filter couldn't catch and the diffuser would. Maybe our wonderful "reformulated" gasoline was the source....

just found this thread very helpful

i couldn't remove the second jet using the flat head because it was so tight

so i drilled it out

and now the bike ticks over beautifully

thanks

Great to hear I'm not the only one that had a right faff on with that second jet. I ruined the thread and figured that it was a new carb job (only cost me £20). Interesting to hear that it runs well without the jet - so basically I now have a spare. Happy days.