Fuel Taps for Commando?

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When I put my 1972 Commando together in the mid nineties, I found a steel tank to replace the suspect glass one. At the time, these fuel taps were thought to be very good and they were ordered and installed. Outside of being hard to move, they seemed to work fine. After sitting a dozen years with fuel in the tank, today it was time to drain off the old fuel through a coffee filter into a funnel and then into a fuel container. The gas still smells like gas and went into the old Dodge gas tank, that car isn't fussy about such things.

Draining off the fuel should have been a five minute job, but the taps were very slow and the job turned into something like half an hour. The flow was very dribbly and I have real doubts the motor could be sustained with such a poor supply at any decent power setting. The taps look like they might come apart for cleaning, but there is very little crud on the screens and I doubt that would help them.

What taps work well with the Commandos? Now is the time to change them out while the bike is apart for other work.

Fuel Taps for Commando?


Vintage Paul
 
hudson29 said:
Draining off the fuel should have been a five minute job, but the taps were very slow and the job turned into something like half an hour. The flow was very dribbly and I have real doubts the motor could be sustained with such a poor supply at any decent power setting. The taps look like they might come apart for cleaning, but there is very little crud on the screens and I doubt that would help them.

The problem with those taps is that they contain a tubular rubber(?) seal which can expand or turn inside the tap body and thus seriously reduce the flow rate.
If you set them to ON, and hold them up to the light and look through them, the restriction caused by the seal is often apparent and can be cleared by running a suitably sized drill bit right through the valve part of the tap. They can be dismantled-but it's often not worth the effort.
 
L.A.B. said:
The problem with those taps is that they contain a tubular rubber(?) seal which can expand or turn inside the tap body and thus seriously reduce the flow rate.
If you set them to ON, and hold them up to the light and look through them, the restriction caused by the seal is often apparent and can be cleared by running a suitably sized drill bit right through the valve part of the tap. They can be dismantled-but it's often not worth the effort.

+1. I had to perform that surgery on these brand new... Have worked fine since almost 2 years now.

Cheers,

- HJ
 
You need at least 10 fluid oz per minute from each tap to supply the commando engine at its maximum HP point.

More to Dave's post, the BAP petcocks shown in the OB photo are particularly well made and work well indeed; some on the forum object to their looks. Mine have been in use for the past two years and flow 20 fl. oz./min., more than any commando engine will require.
 
rick in seattle said:
You need at least 10 fluid oz per minute from each tap to supply the commando engine at its maximum HP point.

10 oz/min would be aproximately 1 gal every 12 min. Seems a bit thirsty to me. I've run a couple hours at 60+ mph but didn't have to fill up this often. Possibly I'm not running near full HP at that point.
 
Jim,

Maximum HP for a Commando occurs near 7000 rpm, where this fuel flow is required. We had a robust discussion in the forum on this topic last year:

fuel-flow-rate-for-commando-850-t6031.html

There is a bit more discussion found on BritBike this year.

Not to worry at 60 mph. My post was directed at the petcock flow requirement, in the most demanding situation. None of us want the petcock to be limiting performance.

Rick
 
The only taps I have found that are worth a crap are BAP taps from Italy. I have 'em on all my bikes and none of them have ever leaked......ever.

Fuel Taps for Commando?
 
Thanks guys, I'll get a set of the BAP taps on order. These look simple & I like simple.

Vintage Paul
 
BAP taps are great but they don't last forever. After 50,000 - 60,000 miles, you can find yourself taking out the sealing rubber and turning it round to expose the unworn side. :)
 
79x100 said:
BAP taps are great but they don't last forever. After 50,000 - 60,000 miles, you can find yourself taking out the sealing rubber and turning it round to expose the unworn side. :)

This sounds like a 50,000mile belt change post from a few weeks ago.
 
OK, I'm convinced.
Placed an order tonight for a pair of BAP taps. Hopefully they'll banish the petrol streaks on the timing case, at least for a while.
 
I had to put some Aviation gasket sealant on the threads to keep the fuel from leaking around the threads, even with the statoseals. Otherwise they seem fine.

Dave
69S
 
DogT said:
I had to put some Aviation gasket sealant on the threads to keep the fuel from leaking around the threads, even with the statoseals. Otherwise they seem fine.

Dave
69S

I don't think that type of seal is designed to seal the thread, standard bonded/Dowty washers won't work.
There are similar types that do seal the thread or the other good ones are a rubber filled copper U section crush washer, the rubber squeezes out into the thread.

Edit - found a link
Fuel Taps for Commando?
 
The one on the right is what I got from Old Brits.

Fuel Taps for Commando?


At $3ea they aren't cheap but they don't leak. Should be able to get same thing from other sources.
 
Those OB statoseals look better than the ones I got from Walridge years ago. Maybe the OB ones would work without the sealer on the threads, but so far I'm not having any problem with the petcocks leaking either through the threads or through the BAP tap.

All my clear fuel line from OB has turned blue from the avgas.

Dave
69S
 
I had really good results with a heavy-duty PTFE thread tape I got from Ace hdw for about $5 a roll. Their brand was yellow. It was with the plumbing supplies, and specifically says on the packaging that it will handle gasoline. They sell it for people putting threaded pipe into home (natural) gas lines. At any rate - I had been fighting oozing and leaks for YEARS with other sealing attempts, but have leaked nary a drop since the PTFE. I would be interested if anyone else has used this stuff with same or other results.

-OG
 
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