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Carb help

Submitted by anthony_haynes on Mon, 22/05/2023
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Commando

I have been struggling to get my 1974 850 mk2 to tick over it was fine but the rh carb was flooding so i decided to strip both 932 amals down and fit new stay up floats while i was at it i fitted new float valves,needles and needle jets cleaned all internals and blew out with compressed air.re assembled and fitted and the bike fires up ok with a few pops and splutters, i have fiddled around with the air screws and throttle screws but cannot get it idling right.I dont realy know what i am doing and need help.I live in Congleton cheshire and wondered if there is a member within striking distance that could come round and help me out.I dont mind paying cash for any help given and fuel used getting to me.

Thanks

Submitted by mikael_ridderstad on Mon, 22/05/2023

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What I learned from a couple of stay up floats is that you always have to correct fuel height. Instructions can be found on the Burlen website.

Submitted by david_cooper on Tue, 23/05/2023

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If it was fine (apart from 'flooding') before, then the fixed settings (needle, slide, jets) won't be different.  So what might have changed?

Are the needles both at the same height as each other and both clipped where they used to be?

Are both pilot screws the same distance unscrewed as they used to be?  Usually start with both 1.5 turns out.

Are both slides fully closed when throttle is closed, and lifting exactly the same amount at exactly the same time?

Are there any air leaks at the flange joints?

Do you have a balance tube between the flange spacers and issue to it in good condition and properly fitted?

Are the float needles closing properly?  If only carb flooded, was it simply the fault of the float needle? Modern ones have Viton tips and seal very well.  Old ones were solid nylon and didn't always cut off the fuel reliably.

Most of the checks don't require prior knowledge or skill, but just attention to details.

Good luck!

Submitted by anthony_haynes on Wed, 31/05/2023

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I have checked everything and all ok apart from the fuel level in the bowls was low so adjusted the stay up floats also fitted aluminium float needles instead of brass along with new needles and jets new air filter, plugs and leads this has greatly improved starting now 1 or 2 kicks and tick over better but not yet right. Reached out to Nick from the north west branch who was very helpfull and has put me in touch with a member who can help. Thanks for everybodys input.

Submitted by anthony_haynes on Wed, 31/05/2023

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Just 1 more thing when i removed the needles the clip was in the lowest groove ie the groove furthest away from the 4 identification rings is that right? i put it in the same groove on the new needles would this affect anything?.

 


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