fuel coming out of vent tube

[t&tkennels]

my '78 has a sudco mikuni carb on it , less than a year old . it has never given me any problems until last sunday. i rode it for about 45 mins & went back home ,shut it off & shut the gas off as i always do , started it back up a few hrs. later & gas pours out the rear vent tube , i shut the bike & gas off it stoped started it back up no gas leaking. started it up today , ran for 1 min. and started leaking gas again , shut off bike & fuel , turn gas back on started it up & no gas leaking . could it be a piece of trash causing this ? thanks for any help regarding this .

[IronMick]

Originally Posted by t&tkennels

my '78 has a sudco mikuni carb on it , less than a year old . it has never given me any problems until last sunday. i rode it for about 45 mins & went back home ,shut it off & shut the gas off as i always do , started it back up a few hrs. later & gas pours out the rear vent tube ...

I am not familiar with that carb, but if that is an overflow tube, then probably there is a piece of crud getting stuck at the needle valve where fuel flows into the bowl.

A common method to temporarily solve the problem is to shut off the fuel, run the engine until the bowl is empty, then turn on the fuel again. The sudden rush of fuel in often dislodges the crud. This appears to be happening in your case.

Need to dismantle as far as removing the bowl and clear it out. Might also check the fuel tank - clear or rust? - the crud has to originate from that direction.

Some guys [try to] remove the bowl with the carb in the bike. IMO this is a bad idea - best to remove the carb from the bike and work on the bench.

[redneck-rider]

What you have is a dirty carb, Do you have an inline fuel filter?, If not clean out your tank,carb, and add a fuel filter in line, After the tank before the carb, The problem you have is the float is sticking causing it to flood over in the bowl, Try this and this will fix the problem you have, very easy fix you can do it your self as long as you have the know how....good luck

[garbiker]

YOU always need the small inline filter. As the tanks will let some trash in the gas line if you have one replace it. AND do the shut off and run till it stops as on the above post and turn the gas back on as he said can flush the needle and seat. BUT you will then have it in carb bowl and can get in the main jet and plug that or slow it down (lean it out)So if this helps clean bowl when you can. good luck gar

[jharback]

Follow IronMick's instructions and start turning the petcock to the off position every time you shut the bike off. This is a good habit to get in to.

[ridefree1]

had the same problem on my 75, did what mick and redneckrider said, flushed it and now it runs fine, mik knows what hes talking about

[Crush]

My 87 did the same thing. Turned out I let me tank run low (read empty) the crap dried up and when I refilled it the crap lifted up and passed the petcock filter straight into the carb. I cleaned the carb twice before I realized the source of the crud (Im not the brightest bulb when it comes to maintenance).