AMAL Bowl Drain Plugs

Tornado said:
The reason is likely they didn't want folks over torquing them or, folks having to cart around a large enough spanner to R&R them instead of a coin or a thick washer like I use.
Click to expand...
Very fair point! I've never lost one, but nothing like unlocking a new worry.
 
I got rid of the stock plugs in favor of a design I saw that someone else had developed and presented at the 2018 norton rally in Elma Wa.
AMAL Bowl Drain Plugs


This method doesn't bend the ears of the bowl instead it puts force on the bowl from the center of the bowl, so it seals the float bowl really well. Here's the breakdown below on how it works.

AMAL Bowl Drain Plugs


I've since modified the tube with extra holes to resist cavitation by letting air escape from around the jet at WOT.

AMAL Bowl Drain Plugs
 
No one mentioned that early Concentrics had no drain plugs. Have one BSA B44VS built in Nov -69 and one built in Mar -70. First one without drain plug.
 
Mike40M said:
No one mentioned that early Concentrics had no drain plugs. Have one BSA B44VS built in Nov -69 and one built in Mar -70. First one without drain plug.
Click to expand...
My January ´69 Trident didn't have drain plugs either. I've been told that they were fitted from about April ´69?
 
Drain plugs and waterproof ticklers were supposedly introduced on Commandos during 1972 from serial number 208628.
 
These will go in a Concentrics bowl. I use them on race bikes and they don't fall out. No washer necessary. Just nip them up and no issues.
 

Attachments

  • AMAL Bowl Drain Plugs
    Screenshot_20250502-224409_Chrome.jpg
    75.2 KB · Views: 126
Last edited:
Always preferred the plastic plugs. The old red hard washer can be reused for a long time but is harder to get weep pruff (TM). The newer thick green washer will not leak but not so happy to be reused much. Since with
ethanol petrol you will be draining the carbs often you can see the rub.
50p coin ( the ones with Her Late Majesty work best) will be available to off shore types for 5 US Dollars each
plus postage. Get in touch...
 
I always removed the jet covers on my Mk2 Amals after racing. I'm sure they have flats for a spanner and there are no gaskets. A Mk2 Amal is similar to a Mikuni.
 
acotrel said:
I always removed the jet covers on my Mk2 Amals after racing. I'm sure they have flats for a spanner and there are no gaskets. A Mk2 Amal is similar to a Mikuni.
Click to expand...
On race bikes yes it is sensible to remove the pilot jet screw and the drain plug and blast carb cleaner through everything. Especially if your on methanol.

But race bikes live in a different world and get a lot more of a high rpm hammering so for a street bike I just turn off the gas and let the bike idle to empty. Maybe in the Northern climate and your winter storing for months you could add the cleanout with carb cleaner. With Allen BA cap screws on the bowl and carb top and monobloc drain plugs i have had no issues in decades.

However on a KTT Velo at a race meeting recently those horrible Phillips BA screw screws fell out and the bowl came close to falling off. All this after a Gardener carb failed to behave and they substituted a big Concentric. So personally I'd worry a lot more about those Phillips screws falling out than the drain plug.
 
Last edited:
I've now lost my 2nd drain plug this season while on a ride. Thought I had it tight enough. Replaced using blue Loctite to see if that will help. The replacement plugs are still coming with hard fiber gaskets. Emailed Amal and response below. Apparently they have no solution yet.


Customer Services <customer.services@burlen.co.uk>​

to me
Customer Services <customer.services@burlen.co.uk>
6:30 AM (11 hours ago)
to me

Hello Dave.



Thank you for your email.



We are aware of this issue, and we have been trying out various different materials to ascertain the best for the job.



Currently this is still being evaluated, so at present we are still supplying the hard fibre washers until further notice.



Kind regards





Robert Houlette
Technical Sales Advisor

Burlen Limited - The SU, AMAL & ZENITH Carburetter Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA

AMAL Bowl Drain Plugs

[td]
6:30 AM (11 hours ago)

[/td]​

Hello Dave.

Thank you for your email.

We are aware of this issue, and we have been trying out various different materials to ascertain the best for the job.

Currently this is still being evaluated, so at present we are still supplying the hard fibre washers until further notice.

Kind regards



Robert Houlette
Technical Sales Advisor
Burlen Limited - The SU, AMAL & ZENITH Carburetter Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA
 
Cuppy said:
I've now lost my 2nd drain plug this season while on a ride. Thought I had it tight enough. Replaced using blue Loctite to see if that will help. The replacement plugs are still coming with hard fiber gaskets. Emailed Amal and response below. Apparently they have no solution yet.


Customer Services <customer.services@burlen.co.uk>​

to me
Customer Services <customer.services@burlen.co.uk>
6:30 AM (11 hours ago)
to me

Hello Dave.



Thank you for your email.



We are aware of this issue, and we have been trying out various different materials to ascertain the best for the job.



Currently this is still being evaluated, so at present we are still supplying the hard fibre washers until further notice.



Kind regards





Robert Houlette
Technical Sales Advisor

Burlen Limited - The SU, AMAL & ZENITH Carburetter Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA

AMAL Bowl Drain Plugs

[td]
6:30 AM (11 hours ago)

[/td]​

Hello Dave.

Thank you for your email.

We are aware of this issue, and we have been trying out various different materials to ascertain the best for the job.

Currently this is still being evaluated, so at present we are still supplying the hard fibre washers until further notice.

Kind regards



Robert Houlette
Technical Sales Advisor
Burlen Limited - The SU, AMAL & ZENITH Carburetter Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA
Click to expand...
The problem remains. The ones they were testing months ago when I last wrote about it are good as were the originals. When tightened with a US quarter (~2.5 cm coin), they do not come loose and they do not leak. But, they've had enough of the 50+ years of complaints of them cracking and leaking from being over tightened!

I have a small stock of the Wassell washers that if coin tightened seem OK. They are NOT the same quality as the originals, but they are not hard fiber and are thicker. They are $2.00 each + shipping. It's too much a PITA to ship in an envelope so shipping to the US is $10.60. Highly advisable to get other small things at the same time! I have a few AMAL drain plus left. They are $5.00 each.

I used up/gave with carbs set the R&D washers AMAL sent me.

You can also wrap with Teflon tape usable with gasoline (usually yellow), use the hard fiber washer, and tighten like a gorilla. BTW, plumbing Teflon tape (usually white) is not usable for the purpose!
 
marshg246 said:
The problem remains. The ones they were testing months ago when I last wrote about it are good as were the originals. When tightened with a US quarter (~2.5 cm coin), they do not come loose and they do not leak. But, they've had enough of the 50+ years of complaints of them cracking and leaking from being over tightened!

I have a small stock of the Wassell washers that if coin tightened seem OK. They are NOT the same quality as the originals, but they are not hard fiber and are thicker. They are $2.00 each + shipping. It's too much a PITA to ship in an envelope so shipping to the US is $10.60. Highly advisable to get other small things at the same time! I have a few AMAL drain plus left. They are $5.00 each.

I used up/gave with carbs set the R&D washers AMAL sent me.

You can also wrap with Teflon tape usable with gasoline (usually yellow), use the hard fiber washer, and tighten like a gorilla. BTW, plumbing Teflon tape (usually white) is not usable for the purpose!
Click to expand...
somebody could design a new plug which has a smaller plug in centre, with a really good (tapered?) seal, then loctite/ whatever main plug in.
 
Quick drain aircraft type are the answer. You will have to drain regularly. But cost is not pleasant.
 
johnm said:
These will go in a Concentrics bowl. I use them on race bikes and they don't fall out. No washer necessary. Just nip them up and no issues.
Click to expand...
Seriously guys. If you have a problem use these. 12 years of racing with an engine bolted into a feather bed frame and they never came loose. They metal on metal seal with no need for any gasket. Combined with Allen BA cap screws on the bowl and carb top the carb stays in one piece. Always.
 

Similar threads

o0norton0o
Float bowl drain bolt that also grips the jet holder..
Replies
19
Views
1,636
Tornado
Tornado
Woody850
  • Locked
BAP Tap and bowl drain leaks.
2 3
Replies
43
Views
5,110
elefantrider
elefantrider
Jerry Doe
  • Locked
Check your Amal float bowl drain plugs
2 3
Replies
51
Views
6,435
MexicoMike
MexicoMike
D
Alton Installation tips
Replies
0
Views
702
DennisMo
D
Ron L
P11 oil tank drain plug
Replies
18
Views
1,976
Ron L
Ron L
Back
Top