Leaking fuel line at carb

C

cstreit911

Joined
Oct 5, 2022
Messages
22
Country flag
I'm getting seeping from the banjo bolt in my float bowls on the '71. I tried some hylomar and don't dare tighten the fittings any more.

Thinking about some dowty washers to fix this, but anyone have any more simple solutions?
 
What have you been using up to now?

The seal for metal* banjos is the Amal 13/163 fibre washer and I haven't known them to leak if in good condition.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

*(The original nylon banjos sealed tight to the banjo bolt so didn't have a washer and why the fibre washer isn't listed in the parts books.)
 
Fiber on the bolt, nylon screen flange on the carb.

I polished those faces with crocus cloth.

Some DPO 🦍 had left diamond shaped marks from clamping the SEALING surfaces in a vice (to remove a stubborn hose, I'd guess)
 
Over tightening can haunt you too.
I do use Dowty washers with dry no drip no seep results.
 
I believe i tried fiber washers once... I think I'll try the Dowty washers this time. Can't find a good diagram of what was originally there, and I have an aversion to gratuitous silicone use in and around engines.
 
cstreit911 said:
I believe i tried fiber washers once... I think I'll try the Dowty washers this time. Can't find a good diagram of what was originally there, and I have an aversion to gratuitous silicone use in and around engines.
Click to expand...
Silicone won't work as gasoline dissolves it pretty easily.

Dowty should fine. I've had recent issues with seeps on brand new Premiers. The seeps appeared to be from the stainless bowl drain caps, but initially I thought it was the banjo fittings. New fibre washers didn't fix. New Dowty's did. But after winter storage with bowls drained, found the first set of Dowty's need to be replaced with new as they were now leaking. Wondering if the stainless caps or the sealing surface of the bowl has a burr. The old plastic caps sealed easily.
 
cstreit911 said:
I believe i tried fiber washers once...

Can't find a good diagram of what was originally there,
Click to expand...

Originally, it should have had the 'H' fuel line with white plastic/nylon single spigot banjos and no banjo bolt washers.
Leaking fuel line at carb

Leaking fuel line at carb

If the banjos are metal then sealing washers are required:
Leaking fuel line at carb


Tornado said:
New fibre washers didn't fix. New Dowty's did. But after winter storage with bowls drained, found the first set of Dowty's need to be replaced with new as they were now leaking.
Click to expand...

Dowty washers can also fail when in contact with (modern?) fuel. Here's one from a fuel tank to tap connection that failed.
Leaking fuel line at carb
 
L.A.B. said:
Originally, it should have had the 'H' fuel line with white plastic/nylon single spigot banjos and no banjo bolt washers.
Leaking fuel line at carb

Leaking fuel line at carb

If the banjos are metal then sealing washers are required:
Leaking fuel line at carb




Dowty washers can also fail when in contact with (modern?) fuel. Here's one from a fuel tank to tap connection that failed.
Leaking fuel line at carb
Click to expand...
Thanks L.A.B.
I had (have) never seen nylon banjos on a bike.
And I've looked at hundreds.
 
cstreit911 said:
I'm getting seeping from the banjo bolt in my float bowls on the '71. I tried some hylomar and don't dare tighten the fittings any more.

Thinking about some dowty washers to fix this, but anyone have any more simple solutions?
Click to expand...
Hello,
When I had a similar issue it turned out to be poor threads in the float bowl (new) such that the banjo bolt was not clamping the filter, banjo and fibre washer properly.
I ended up using a tap (fairly sure it's a 3/8" 26 tpi - cycle thread) to clean up the banjo threads in the float bowl and all was well.
Shouldn't really need loads of force and different washers provided threads and surfaces are ok.
Also worth checking that fuel lines are not leaking and the fuel finding its way down to the banjo bolt.
Hope this helps.
Andy
 
concours said:
Thanks L.A.B.
I had (have) never seen nylon banjos on a bike.
And I've looked at hundreds.
Click to expand...

The subject of plastic/nylon banjos has cropped up before.
Previous thread.
www.accessnorton.com

Amal carb fun facts

I've got the impression over the years that these washers are a bit of a secret, e.g. Andover Norton doesn't list them on the relevant page for my bike, or another one that I just checked at random for a '71 750. And they're not in the parts books that I have. My experience, though, has been...
www.accessnorton.com www.accessnorton.com
 
L.A.B. said:
The subject of plastic/nylon banjos has cropped up before.
Previous thread.
www.accessnorton.com

Amal carb fun facts

I've got the impression over the years that these washers are a bit of a secret, e.g. Andover Norton doesn't list them on the relevant page for my bike, or another one that I just checked at random for a '71 750. And they're not in the parts books that I have. My experience, though, has been...
www.accessnorton.com www.accessnorton.com
Click to expand...
Thank you.
 
VEry helpful, thank you for the diagrams LAB.

I have the H fuel like with nylon banjo's as you've pictured above. I'll try cleaning up the mating surfaces and see if that works.
 
L.A.B. said:
What have you been using up to now?

The seal for metal* banjos is the Amal 13/163 fibre washer and I haven't known them to leak if in good condition.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

*(The original nylon banjos sealed tight to the banjo bolt so didn't have a washer and why the fibre washer isn't listed in the parts books.)
Click to expand...

I've been using a paper towel to soak up the slow drip. :) Its not a lot and not a safety thing as its minimal - but this is something that I think should be fixable and it bothers me...
 
DevonNorton said:
Hello,
When I had a similar issue it turned out to be poor threads in the float bowl (new) such that the banjo bolt was not clamping the filter, banjo and fibre washer properly.
I ended up using a tap (fairly sure it's a 3/8" 26 tpi - cycle thread) to clean up the banjo threads in the float bowl and all was well.
Shouldn't really need loads of force and different washers provided threads and surfaces are ok.
Also worth checking that fuel lines are not leaking and the fuel finding its way down to the banjo bolt.
Hope this helps.
Andy
Click to expand...
Interesting. Wondering if poor threads in the bowl drains is root cause of my drain stainless cap seeps?
 
cstreit911 said:
I've been using a paper towel to soak up the slow drip. :) Its not a lot and not a safety thing as its minimal - but this is something that I think should be fixable and it bothers me...
Click to expand...

The old nylon banjos could have distorted.
Most have been replaced with metal banjos.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
 
L.A.B. said:
The old nylon banjos could have distorted.
Most have been replaced with metal banjos.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
Click to expand...
Thanks. I have the Andover kit installed. Put it on end of last year.
I'm going to try just cleaning up the mating surfaces with some 1000 grit on a sheet of glass. If that doesn't work I can get viton dowty washers that will holdup to the fuel I think.
 
Just buy a couple of new filters the plastic flanges are soft enough to accommodate any deformaties in the surfaces
 
You must log in or register to reply here.

Similar threads

o0norton0o
Float bowl drain bolt that also grips the jet holder..
Replies
19
Views
428
Tornado
Tornado
Tornado
My Commando Is A Jealous Be-atch!
Replies
16
Views
532
Tornado
Tornado
Woody850
BAP Tap and bowl drain leaks.
2 3
Replies
43
Views
2,332
elefantrider
elefantrider
marshg246
AMAL Bowl Drain Plugs
Replies
9
Views
328
Triton Thrasher
Triton Thrasher
D
How I finally got my primary chaincase cover leak free !
Replies
7
Views
213
DennisMo
D
Back
Top