Sinking float on RH Amal Mk.1 920 carburettor?

Hello Charles.

It would seem that 2 and 3 are related to the flooding of the float chamber, but could you clarify what you mean by 'hard to tickle?' Do you mean that you depress the tickler and then have to wait a long time for fuel to emerge? If so, this doesn't sound like its directly as a result of a sinking float, but maybe dirt on the float needle/seating (and maybe a partially blocked fuel tap filter.)

Are both fuel lines connected? If so, If you flood the l/h carb first, does the r/h carb flood more quickly? This may point to the r/h tap filter.

In any event, I would take-off the r/h float bowl and look at the float and valve. It will be obvious if the float has fuel in it (give it a shake.) Also examine the rubber tip on the needle. If there's a ring mark where it closes against the seating, then renew it.

As part of recommissioning my Commando, I have fitted new valves and stay-up floats as a matter of course. Time will tell if they are ethanol-resistant!

Allan.

One other thing to watch is the width of the float across the pivot. Older Amal floats can jam between the body casting. It happened when I replaced 7 year old bodies with the newly tooled casting but these were 932's. Also worth checking that the float pivots freely on the brass pin. On mine they were tight and could hang up or down.

Hi Charles

I would remove carbs from bike and stip down. Check floats for any leakage check condition of needle vlves and seat, give every thing a good clean. Make shure the float is free and neele valve is seating correctly.The iratic idle may be caused by apartially blocked pilot jet. (I recently unblocked mine an it transformed the low speed running of the bike). Fit new float bowl gasgets on re assembly.

I have also had problems with a relatily new fuel tap not passing fuel (not a blocked filter) seems modern fuel may caused something inside the tap to swell and restric flow.

Their is a very interesting artical on carbs at http://motos-anglaises.com/- Technique - Carburation - Tout sur les amal in english.

Peter

Previously wrote:

Twice this year I have had the following problem which developed progressively:

1. RH Carb hard to tickle.

2. Throttle pick up erratic when cold.

3. Erratic idle on RH cylinder

4. Float bowl flooding continuously, only stopping when petcock closed.

The first time I had the float bowl assembly replaced complete, which cured the problem for about 6 months/1000 miles.

Internet research is suggesting to me that Amal floats are perforated by Ethanol and then sink. Burlen have apparently developed a "stay up float".

An 850 owner on another website reported virtually identical symptons - with the right hand carb.

Any comments/ideas would be greatly appreciated.

Thanks very much.

Charles