Amal problems

'72 Commando with 932's misses when accelerating briskly. If I nurse her to road speed it's smooth, but if you goose her, she cant handle the fuel. Just switched to NGK Iridiums, 'cause upon inpection the plugs were pretty black and was difficult to start. Again, if I accelerate slowly it runs fine thru the gears. Thinking about a single Mikuni, but would like to keep the bike original. Think it's just the floats ? Thanks

hostilecarl said:

'72 Commando with 932's misses when accelerating briskly. If I nurse her to road speed it's smooth, but if you goose her, she cant handle the fuel. Just switched to NGK Iridiums, 'cause upon inpection the plugs were pretty black and was difficult to start. Again, if I accelerate slowly it runs fine thru the gears. Thinking about a single Mikuni, but would like to keep the bike original. Think it's just the floats ? Thanks

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What is your skill set? Ever done any carb rebuilding on cars? Accomplished Mikuni veteran? Do you WANT to keep the 932's? Or prefer plug and play?
If you want help troubleshooting, we'll need tons more info. Have you been into the carbs? Total miles on them? Any brass been checked/replaced? (Needle jet)

If you are talking about a WOT (Wide Open Throttle) type of exceleration event, then try going down in the main jet.

Try slides with smaller cut aways. sounds classic fuel starvation, the vacuum drops and no fuel gets "sucked" in.

The black plugs would indicate the mixture is too rich - assuming it's fuel fouling and not oil fouling. But too rich where? Most likely at the low end of the RPM/load range since that's where the bike is most of the time. There are a ton of sites re adjusting Amals, and plenty of info on this site as well.

Read up on the procedure for evaluating the jetting/idle/needle position and go from there. But first the carbs themselves have to be clean, mating surfaces trued and everything in top shape...including the slides.

Amals get a fair bit of bad-mouthing but they are excellent carbs as far as tuning/performance is concerned. You can't compare a 40 year old, clapped out Amal to a new carburetor and then complain about the Amal. If you put the Amals in the same condition as the new carb(s), they won't give away anything to any other standard carb and they will produce more power than a single carb.

hostilecarl said:

'72 Commando with 932's misses when accelerating briskly. If I nurse her to road speed it's smooth, but if you goose her, she cant handle the fuel. Just switched to NGK Iridiums, 'cause upon inpection the plugs were pretty black and was difficult to start. Again, if I accelerate slowly it runs fine thru the gears. Thinking about a single Mikuni, but would like to keep the bike original. Think it's just the floats ? Thanks

Click to expand...

Don't forget the old adage: "99% of carburetor problems are electrical in nature" :wink: