Carb leaking

[SEAGULL]

I have a 86 softail FXSTC. The Mikuni carb seems to have leaking petrol from the overflow tube when she's been parked for a while when not in use, especially when kept in a warm place, i.e at work! Can anyone suggest whats causing this and how to fix? Thanks, Graham

[pete376403]

I'd suggest the float level is a bit high, and as the gas in the carb expands from 1. the warm parking place and 2. heat soak into the carb once you park the bike after riding*, causes the gas to come out the overflow.
I suppose Harleys dont have centre stands so the bike is parked on an angle (side stand) possibly this puts the carb overflow at a lower level than if the bike was upright.
* carbs usually are pretty cold when the engine is running due to the heat being absorbed by petrol atomising / vapourising (call it what you will)

[merv]

If it just keeps on leaking while its parked then you've got a needle valve problem letting the fuel through from the tank when it shouldn't be.

[White trash]

I have a 86 softail FXSTC. The Mikuni carb seems to have leaking petrol from the overflow tube when she's been parked for a while when not in use, especially when kept in a warm place, i.e at work! Can anyone suggest whats causing this and how to fix? Thanks, Graham

Yep, sounds like a stuck needle valve to me, Graham. on an 86 Softail, I'd say it may be worn out too.

luckily, H-D's are among the easiest bike on the planet to work on so shouldn't be a major. Let me know if you need a hand.

[k14]

Don't mention carbs again. Mine started leaking again today. Had to take them and everything off and put it back on 3 times today

So I think you will believe me when I say I can take my carbs of in less than 5 mins now.

Atleast it isn't leaking anymore, untill the gasket goo stops working I suppose.

[SEAGULL]

Thanks for the advice Pete. Now you highlighted these things it all seems to fall in place. I also found out last night, by loosening off the petrol caps, also seemed to work too by, I think, reducing the pressure build up in the tank. Thought this might be creating a syphoning effect, what do you think? Graham

[SEAGULL]

Yep, sounds like a stuck needle valve to me, Graham. on an 86 Softail, I'd say it may be worn out too.

luckily, H-D's are among the easiest bike on the planet to work on so shouldn't be a major. Let me know if you need a hand.

Thanks for the offer. I also found out last night, by loosening off the petrol caps, also seemed to work by, I think, reducing the pressure build up in the tank. Thought this might be creating a syphoning effect, what do you think?