Amal flooding

vibrac

Well Known and Active Forum User
VOC Member
This isnt on a Vincent but its the same float chamber bottom feed 276
I have a good copper float and I have brasso'd the taper till it seals well
I have added fuel filters to the taps but it floods till I 'tap' it with my toe (Its a cammy velo so i'm allowed to:p)
my gut feeling is the float does not exert enough pressure on the taper
NB the bike is not on a side stand it occurs even if bike is upright
Once the engine starts the vibro and fuel demand stops any re occurrence
Any thoughts?
 

Mike 40M

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VOC Member
In my not so vast experience, leak is an inbuilt feature in the design. Last time I tried to fix a leaking float chamber on my Norton 16H, I gave up and bought a new float chamber from the Spares Company. At that time Burlen had no ones.
 

Sakura

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Non-VOC Member
The separate float chambers have a definite tendency to flood as they age. If you lap the seat it gets wider. The wider the seat, the more difficult it is to get it to seat. Try facing the seat to get back to a knife edge.
 

vibrac

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VOC Member
The separate float chambers have a definite tendency to flood as they age. If you lap the seat it gets wider. The wider the seat, the more difficult it is to get it to seat. Try facing the seat to get back to a knife edge.
Not sure of where you are suggesting facing do you mean reducing the length of the taper to thus reduce the area of contact of the cone? Would reducing the length of the cone not have the same effect? I know burlen have introduced stay up floats for monoblocks was that because of the change of SG of so called petrol?
 

Sakura

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Non-VOC Member
Not sure of where you are suggesting facing do you mean reducing the length of the taper to thus reduce the area of contact of the cone? Would reducing the length of the cone not have the same effect? I know burlen have introduced stay up floats for monoblocks was that because of the change of SG of so called petrol?
It's a long time since I have done this so memory is hazy but I am talking about cutting the seat back to a flat surface and then lapping, if necessary, a narrow seat. Martin Bratby actually sells replacement seats for bottom feeds.
 

vibrac

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VOC Member
I did notice that the spring clip on top of the float was bowed out 'high' this could mean that it contacted the top of the float chamber where it protrudes to provide a guide for the float valve stem perhaps that tended to make the contact on the valve seat less firm.
Also there were small deposits of 'skin' in bottom of bowl I am sure I cleaned it within the year, my petrol is always esso non ethanol the tank has no sealant and I have good filters on the taps very strange.
 
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