--Bike Carbs - Fuel weeing back out of Jets?

[danny_p]

the way i put carbs on enignes


the level up the the join betweeen the float bowl and carb ,   getting the floats to sit right is the most inportant bit,   there are fuel dains from the bottom of each float bowl these get piped to somewheer out the way.

fuel pressure 3 psi will do electric pump and fpr is best way, you can make an fpr with a small valve and a t piece if you want to tho, carbs normaly have a vac take off for the pipe all four together and feed this to the dizzy use a small inline fuel filter if the signal is to bouncy,   attach the brake servo to one runner it's easy and fine for what it needs 

[sidecarphil]

most bikes use gravity only or a small electric pump for the change over whan you nail the throttle wide open and there is not enough quantity not pressure

whan i ran them on my XR3 i used a small solid state fuel pump with about half a psi

the jets were drilled out but i dont know how much

bike carbs dont usually have a return ,

mine ran well with no fuel leakage problems But the cold start was a problem LOL

[fishnchipsx2]

OK thanks for the advice everyone.  We have them running on the road now, no fuel spurting out anymore!  We swapped the valves over for some better ones from a mate's set of old carbs, bent the springs a little bit to change the float angle, re-drilled the jets, bunged up what we thought were fuel return lines but are in fact vacuums, and left the top holes open (the ones that normally have t-pieces on em), and deleted the pressure regulator.

Runs well until about 4000rpm, but I guess this is because we don't have a very good seal on the vacuum for the dizzy advance (or the brakes!). Will sort this out in time to come, and probably buy an electric pump too.