Check your Amal float bowl drain plugs

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Jerry Doe

Jerry Doe

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Last time I rode to a Norton meeting my 750 broke down due to a weird electrical issue. Now on my way to another meeting on my 850 and the right hand float bowl drain plug fell out. Was doing 80 down the freeway. Luckily was able to coast to a nice shady bridge. Mrs is on the way with another drain plug and all will be well in toyland
 

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Jerry Doe said:
Last time I rode to a Norton meeting my 750 broke down due to a weird electrical issue. Now on my way to another meeting on my 850 and the right hand float bowl drain plug fell out. Was doing 80 down the freeway. Luckily was able to coast to a nice shady bridge. Mrs is on the way with another drain plug and all will be well in toyland
Click to expand...
I put a worm drive round the last one secured to something fixed, which covered the next trip to France in 2018 very well. ( feet forward Commando-engined special with Mk3 / single Concentric)
 
Are you saying to put JB WELD on the fitting at the bottom of the float bowl for that large drain plug? If so, NO NO NO!!! If that's not what you meant, I apologize.

If you JB Weld it you lose the two reasons the drain plug exists... to DRAIN fuel and to change main jets without removing the float bowl. ASSUMING the carbs are properly mounted with the OEM manifold, the OEM metal drain plug and an OEM gasket will stay in place if it is just firmly snugged using a large washer or something similar to tighten the fitting.

If you want to use some sort of sealant like Permatex Moto Grey or whatever, fine . But NOT JB WELD!!!
 
My new Premiers had one leaking bowl drain. Could not get it to not drip with different fibre gaskets. Perhaps some poor finishing of the sealing surfaces? Anyhow, I managed to fit a Dowty washer on the plug and though fairly stiff to wind the plug into bowl, leaks fully stopped now.
 
Jerry Doe said:
I will be doing this
Click to expand...
I will use loctite 545 thread locker on mine from now on. The mk3 has been very reliable for 10000 plus miles. I have never had a float bowl drain plug come out before, I need to do a few upgrades and go through and check everything else.
 
Would not be using any type of silicone based sealants (Yamabond etc) nor teflon plumbers tape....both can result in bits coming off into the fuel bowl and doing nasty things to the jets. Threadlocker can also get quite granular when undoing the threads after it has cured....bowl and plugs would need to be very thoroughly cleaned before re-threading. The plastic type drain plugs seem to seal well and stay put. Maybe the SS type are just not mating well with the Amal alloy threads?
 
If you are just sealing the threads that actually touch and not above you wont have an issue. but also we have used Hylomar in a pinch for a bowl gasket with no issues at all
 
Tornado said:
My new Premiers had one leaking bowl drain. Could not get it to not drip with different fibre gaskets. Perhaps some poor finishing of the sealing surfaces? Anyhow, I managed to fit a Dowty washer on the plug and though fairly stiff to wind the plug into bowl, leaks fully stopped now.
Click to expand...
A Dowty washer sound like a great idea. Friction fit.
 
Why not just safety wire the plugs? Wouldn't surprise me if you could purchase metal plugs already drilled for safety wire, but isn't all that hard to do if you can't.

The ease of being able to change main jets without dropping the bowels isn't so sweet if/when the main jet holder wants to accompany the main jet; a good reason to strip and clean a carb before you mount it and to be able to test main jet removal and add torque to the holder until the main jet can be reliably removed/reinstalled without the holder following.

My experience leads me to believe that the sealing properties of fiber washers evolve; seems like they want to be doped by the liquid they are employed to seal, but you need to keep after them as they "break-in". If they do seal on first use they may not be needed, as one poster stated above.

For Amal float bowels I like the metal plugs as you can safely apply more torque than with the plastic ones. The fiber washers are die cut and, usually, have circumferential ridge on the side that didn't see the die coming; I suggest that the ridge be removed; you may get a V 1.0 seal, but stay on these as they will soak up fuel and with diligence will seal.

Best.
 
MexicoMike said:
Are you saying to put JB WELD on the fitting at the bottom of the float bowl for that large drain plug? If so, NO NO NO!!! If that's not what you meant, I apologize.

If you JB Weld it you lose the two reasons the drain plug exists... to DRAIN fuel and to change main jets without removing the float bowl. ASSUMING the carbs are properly mounted with the OEM manifold, the OEM metal drain plug and an OEM gasket will stay in place if it is just firmly snugged using a large washer or something similar to tighten the fitting.

If you want to use some sort of sealant like Permatex Moto Grey or whatever, fine . But NOT JB WELD!!!
Click to expand...

Easy boys, tongue in cheek, ..didn't mean to mislead.
I have a clue as to the influence of JB weld.
My grandkids of 3 and 5 have been here all day...they are now gone...gummies and beer may be in play...its all good.o_O:)

Motorcycles are my hobby.
Recent build was this block find still wrapped in cosmoline. 1968 427 Ford side oiler. Very hard to find. I sleeved all 8 cylinders due to skinny casting walls, sleeves in liquid nitrogen to insert, all that spooky stuff.
I don't use JB unless there is a crack in my concrete slop sink.

Fiber washers on the Amal drain plugs have done well after 2000 plus.


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Wow. That's not very green. Hope you don't have that out in the open when the grandkids are around.
Wrong impression and all that.
My Norton is very green. LED headlamp and tail as well...
 
Is this a 'crap fuel' related thing? Maybe the air filter restricts access, but I found a stubby screwdriver was fine for accessing the four retaining screws, so why not swap for bowls without drain plugs?
(And if they do need draining to remove stale fuel, just disconnect one fuel pipe at the petrol tap and direct into a suitable jar :-) )
 
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Jerry,
The only time that I had to have my m/c towed was for the same reason as yours. I walked all over the road looking for it for about an hour.The drain plug issue was completely my fault as I forgot to secure it. You are fortunate to have a spare and a wife to find one in your stash.My wife would not know a drain plug from a rolling pin!
Glad you got home
Mike
 
I had one of those drain plugs fall out in the middle of nowhere, very lonely feeling. By a miracle the plug lodged behind the starter motor so I was up and running in no time. Since then I NEVER fiddle with the drain plug. That was about 30 years ago.
Also, for most people there is never a need to change main jets.
 
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