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New Mk2 Amal Tuning for Mk1 850 Interstate.

Submitted by malcolm_patterson1 on Sat, 16/04/2022
Forums
Commando

Hi Advise Please

With a single 34mm carb as above I have the following settings:-

SLIDE   = 3.1/2

PILOT   = 15

NEEDLE JET = 106

NEEDLE IN 2nd GROOVE ON 2a1

MAIN JET = 300

FLOAT HEIGHT SET AT 0.070" BELOW

AIR Screw is out 3+ turns out to get an idle.

Here's my dilemma. Black smoke out of exhausts and really sooty plugs.

It's a new carb and recently overhauled engine.

Advise please oh and choke on lever and I hate it going to install handlebar operation. I have flat bars on any idea what cable I will need as Amal can't help.

Cheers 

See you all at Stafford.

Submitted by tony_ripley on Sat, 16/04/2022

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My question to you is what size carb would you have if you still had twin carbs? Would it by any chance be 32mm? If so then there is no reason to go to 34mm for a single.

I have an 850 MkIII and fitted a 34mm carb with basically the same setup and the same problem.

It gave the impression the choke was never closing properly and it ran lumpy and heavy at tickover, went ok once a few revs on.

Now fitted a 32mm and all is ok. Although it is possibly slightly weak.

Submitted by terry_martin on Sat, 16/04/2022

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Hi, I had trouble with the lever operated chokes on Mk2 Amals not sealing, changed to cable operated and no problems after that.

Terry.

Hi Malcolm

I had a similar problem  with a brand new 34mm Amal Mk2 on my Mk3 Commando.  The choke adds extra fuel to the mix and I found I had a bent choke valve which was not shutting the fuel supply off.  With a new valve it cured the problem.

Submitted by terry_martin on Sat, 16/04/2022

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Hi Malcolm, It will depend on the type of bars you have fitted, I have standard European bars fitted and can give you a rough idea. RGM list a single cable, they also stock the cable pull choke. If you go to their web site and search choke cable both parts will come up.

Best wishes,

Terry.

 


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