mikuni carbs

[kenny z9fighter]

cant get the carbs to stop overflowing on my z900a4
the bikes been stood for about 6 month
stripped the carbs,cleaned em,everything seems fine,put em back on,petrol pissing ot the overflows!
there fitted with dyno jet,engines a 1075 wiseco,do i persivere or change the carbs to summit else?

[bunnysZ]

were they leaking before you stripped them .
have the float valves been put back in the right way ,
or do the floats need adjusting by bending the tab up to prevent the valves letting too much petrol

[kenny z9fighter]

cant remember if they were leaking before!bent the tabs up on the floats slightly,blew into the petrol pipes and moved the floats up and all seemed fine,put em back on the bike,petrol pishing out,arrrrr!

[Steve Cooke]

Can only be incorrect float heights or worn float valves, could be damaged float although unlikely if more than one carb overflowing.

PS. You didn't mix up the needle valves and seats by any chance.

[Garn 1]

Kenny, I had a similar problem and I have heard of others with the same.
The problem could be a hair-line crack down the length of one or more of the brass overflow tubes, inside the fuel bowl.

Very hard to see unless looking for it. I was amazed that it would cause such leakage. I think I cured it with a thin piece of plastic sheathing, or was it solder. The crack usually continues thru into the bottom of the fuel bowl.

RegardZ.

[uk kev]

Do you have a vacume fuel tap? if so is it in the prime position?

[kenny z9fighter]

i've took the carbs of again,cleaned everything,put the floats in a bucket of petrol,they didnt sink,bent the tab up a wee bit more,put them back on the bike,got really cold and came in for a coffee,i'll put the tank on tommorrow and give it a go,the taps not a vacum,just the on,res and of type.what i have noticed is i put a gallon in the tank,in the on position nothing comes out,on reserve only a small drop seems to come out one of the outlets,is this normal?do you need at least half a tank to get sufficiant fuel?

[kenny z9fighter]

bikes running with no fuel leaks,needs a bit of tuning,when the chokes of it wont tick over and when i rev it about 4000 it backfires,maybe cause number 2 exhaust downpipe aint sealed to well?think the lack of petrol things down to the filler cap on the tank,its a harris one,probably needs vented?

[Rich]

You ought to set your fuel heights properly. If the fuel levels fall outside the designed level then all the rest of the carburation will be off.
Your harris cap will certainly need a seperate breather fitting.