Bringing my 250 NC M3 back into action

[Bevel bob]

Not rode it for a couple of years , and last time it was not happy (kept spitting back and stalling ) , so as part of the process i will raise the fuel level a smidgin and enrich the tickover a tad . Cant for the life of me remember whether the pilot screw is in or out to richen on an SSI29D ! The blurb in the Dellorto literature is pretty vague too.

[Bevel bob]

As no one seems to know! i checked and on ssi up to 30 mm the mixture screw is the same as a monoblock in is richer. Over 29 mm its the opposite .

[Bevel bob]

I am doing whatever possible to make my 250 less fussy in traffic and give a more reliable tickover. I have some steel sleeves that i intend to fit in the carb , "think chokes " that may speed up the airflow in the carb and increase the venturi effect , hopefully will help to pick up fuel for the idle. The 29mm SSI is too big , as are the 40 mm inlet and 36 mm ex valves .Cant do much about those. I have a(reputidley) Red cam to fit (which appears little different to a Monza cam?.). I will probably drill a hole low in the carb slide to provide air flow for the tickover , and allow the slide to sit right down . Anyone tried this ? size? . Seen it done on GP carbs with BSA gold stars. No slide in the SSI side chamber ,fill in slot or leave open?. Will definately need a side stand , anyone got one ?. Also still on the lookout for a pair of swann neck bars to replace clip ons.

[blethermaskite]

Are you determined to use the SSI? I would put that on a shelf as an ornament.....I mean they are a race carb and will never really behave on a road bike, fit a mk1 Amal concentric on it (one of their 'new' premier alloy ones) with a proper Amal velocity stack (not a generic bell mouth/trumpet). If you want to calm the bike down stick a low comp. piston in it and get a monza head, it will kook exactly the same but be a nice soft wee bike to ride with no drama. Just my thoughts
Cheers George

[Bevel bob]

Hi George, The carb may have to go , but will try my mods first. i have 7 or 8 suitable carbs , Monoblocks ,concentrics etc .a Mikuni and a brand new vintage sports Bowden that looks very trick .A butterfly carb with side float, a proper choke and chrome bellmouth. A Monza head is a bit too small , A USA Dianna head would be ideal. The 10 to 1 forged carb is only 9 to 1 in the real world .