Carb leak

GoldenMotor.com

Ratt_Bones

New Member
Aug 2, 2013
153
0
0
Appleton, Wi.
Just curious here.
I have a brand schpankin new speed carb, and all the gaskets/seals are good, yet when the bike sits I end up with a small amount of fuel sitting on my crankcase and a slight bit on top of the fuel bowl of the carb.

For the life of me I can't figure out the cause. I just got rid of another NT carb that was doing the same thing.

Any suggestions?

Thanks!
 

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
I suspect it may be a result of atomized fuel being blown-back through the venturi into the filter (sponge). It MAY also be a float mis-adjustment.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
I suspect it may be a result of atomized fuel being blown-back through the venturi into the filter (sponge). It MAY also be a float mis-adjustment.
I agree but also check the fuel line connection at the carburetor. The brass barb, float seat, could be loose.

Are you using the fuel shut-off (petcock) when the bike is parked? Even a good carburetor with good gaskets and seals might drip a little if it sits with a full tank of fuel above it. Always shut the fuel off when the bike is unattended for any length of time. Even motorcycles have fuel shut-off valves. Gravity flow systems do have their drawbacks.

Tom
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
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memphis Tn
The crappy fuel line could be leaking around the fittings.
Even using zipties to clamp the fittings, stock line eventually starts weeping fuel when the alcohol hardens the line so it no longer seals. Try fresh fuel line.
Be aware piston port, non-reed engines will always be messy around the intake. The small stock filter won't catch all the oily blowback. A better air filter will help keep the engine clean longer.
 

Ratt_Bones

New Member
Aug 2, 2013
153
0
0
Appleton, Wi.
I have some really good aftermarket (guaranteed for life) fuel line, I am a little o.c.d. about making sure my lines are shut off after shutting down. I also have a custom cold air intake deal, and just under the air filter I have a fuel overflow drain with a reservoir to collect any unwanted spillage.

I'll check the inlet tomorrow morning, and run to Fleet farm for some fitting clamps to see if that helps. If I still have leakage, then it must be something else.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
how far does the bike lean on the kickstand? even with the petcock off, you may be tilting the bowl enough to leak
 

Ratt_Bones

New Member
Aug 2, 2013
153
0
0
Appleton, Wi.
how far does the bike lean on the kickstand? even with the petcock off, you may be tilting the bowl enough to leak
Ahhhhhh....... I did NOT think about that.
I really need a new kickstand. Like something fierce!


So simple, yet so far from my my mind.
I will rectify this right away and see if it helps.


Thanks!