Author Topic: B40 new carb and timing necessary?  (Read 840 times)

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B40 new carb and timing necessary?
« on: 16 April, 2017, 21:21:44 »
I am currently 2/3 of the way through getting my B40 back on the road and I am close to trying to get it started.

Ive cleaned the carb and replaced the points and the fuel and oil system have been replaced where necessary and cleaned. New coil, HT lead and spark plug.

I was then at my bike mechanics garage picking up my Yamaha from an MOT and service and asked if he had experience in classic bikes. It transpires he is well versed on the BSA and upon discussing mine immediately advised that the original Amal carb will be shot and that I must install electronic timing/ignition. He very matter of fact said that the bike would never run properly unless the carb was replaced and new electronic timing. I feel I should believe him as he has worked wonders on my other bikes.

So do I ignore him and carry as planned.

Give it to him to do and get the bike on the road to enjoy for the summer.

Try and do it myself and if so what carb and what electronic ignition system do I buy???

Any help/advice appreciated.



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Re: B40 new carb and timing necessary?
« Reply #1 on: 16 April, 2017, 22:36:34 »
Has he actually examined your bike?

If not then how does he know you will have those problems?

I would be sceptical.

If it does not run properly after the work you are doing, you can always consider a new carb and electronic ignition, they will not take long to fit.


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Re: B40 new carb and timing necessary?
« Reply #2 on: 17 April, 2017, 10:04:16 »
One of my BSAs is still running on its original Amal carb after 65 years. And it's no trailer queen - it gets plenty of use and abuse. So don't rush to junk the carb. My B40 is still on its points setup. Nothing wrong with that. So just carry on and get the bike up and running and enjoy it. Don't panic!


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Re: B40 new carb and timing necessary?
« Reply #3 on: 17 April, 2017, 17:33:18 »
try it first see if it runs..
1959--A10   1960--AJScsr   1979--MOTOGUZZI-V50


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Re: B40 new carb and timing necessary?
« Reply #4 on: 18 April, 2017, 10:36:08 »
Hi hubcap,
                   He may have knowledge or be concerned with the use of modern ethanol based fuels.  Amal have worked to provide components resistant to them, this maybe worth a read:

I had to buy new carbs, my project never had them in the first place, so I opted for the Premier specification which resists the ethanol effects. You may consider whether you want the expense of replacing/rebuilding them or continue with what you have until there is an issue.

Electronic ignition is a better option. That may provoke many comments, but if it wasn't, all vehicles will still have points etc. (broke my dwell meter awhile back so I'm biased :)). Again you may consider the expense at this stage or ask for it as a Birthday present  ;).

Best wishes...........