Just fitted an Amal stay up float kit to the concentric carb on my bike but now it floods as soon as the fuel is switched on, have tried to lower the float level as well as checking the viton tipped float needles operation but without effecting a cure.

Any ideas please.

They are a bit variable,I have a couple of spare stayup floats,but one of them runs the fuel level too low and I can't tune the carb properly. I think your only chance is to carefully bend it so it will allow shut off, but keep the fuel high enough to allow it to work properly

thought it was just me. Had no end of problems with mine. Have to remember to turn the fuel off before i stop the motor otherwise it floods the engine even if only after 20 seconds. Thinking of trying to get another standard one.

Thank you both for your replies.

So far not so good then judging by your experiences. Looks like the trials rider pays up and does the developement work yet again, we continue to pay the asking price for things that simply do not perform. Any one done any better with these floats?

i had the same problem on my greeves outfit after fitting a new carb , the solution was to fit the old original plastic float and nylon float needle from the 20 year old carb it runs better than ever ,and i have been repairing bikes for 50 years but on my classic sprinter it works great with the new float and needle ,and i can remember altering the length of the needle to alter the float level ,the new float/ needle that gave problems was a genuine , but the float/needle,that works ok is a wassell one i leave you to form your own opinions   will

With the adjustable needle tangs the stay up should be an easy fit but it currently looks as though the old one wil have to be reused.

Thank you both for your replies.

So far not so good then judging by your experiences. Looks like the trials rider pays up and does the developement work yet again, we continue to pay the asking price for things that simply do not perform. Any one done any better with these floats?

I have retro fitted two of these without any problems. has the valve seat in float chamber been drill to adjust float level in the past?? the seat should be just under 15mm from the gasket face.

 

if it is much more turn it upside down and tap the brass seat bush up a bit with a  1/8inch drift.

Edited March 4, 201610 yr by stan wellback

Yes, mine was the same. The float looks to be the right dimensions but the new viton needle is too short and there is no way of adjusting anything as far as I can see. I put the old white nylon one back in and it is fine so far. I'll have a look at your suggestion next time it's in bits Stan, thanks.

Will do the measurements asap, thank you.

Just realised, mine is a Monobloc so the problem seems to be on more than one type of carb.

I have retro fitted two of these without any problems. has the valve seat in float chamber been drill to adjust float level in the past?? the seat should be just under 15mm from the gasket face.

if it is much more turn it upside down and tap the brass seat bush up a bit with a 1/8inch drift.

Carb was new genuine not copy, spec is unaltered.

Measures 15mm from gasket face to needle seat.

Again read the Burlen technical pages before calling their technical help number, though helpful they could offer no real insight as to why the problem was happening but stated that the stay up float wa definitely the way to go saying recheck everything.

Did just that without really finding any differences so reassembled using stay up float with white needle and the problem has gone away, bike runs perfectly.

You can move the brass needle valve seat in the alloy float bowl easily enough,

 

Take the banjo fitting off and heat up the float bowl by putting it in boiling water for a minute then tap the needle valve seat up or down with an aluminium drift.

 

Check the float height by turning the assembly upside down, fine tune it by bending the float tabs slightly

Thanks to all of you for your useful info, the bike is now running very well with the white needle fitted I would however prefer to use the viton type as it is supposed to partner the new float. Thinking about it one possibility could be if the angle is different on the viton needle tip the effective needle length would be shorter? so causing the over fueling. There must be something as we have all had similar problems.