BAP petcock FLOW VOLUME question

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concours

concours

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When I installed the BAP petcocks it was during the last push to get the bike ready for a trip, in a bit of a rush. I remember unscrewing the screen to inspect before I installed, the standpipe for the main side was, IIRC, nothing but a 2" length of clear plastic tubing, but it seemed WAY TOO SMALL to really flow well, in the order of 3/16" O.D., and perhaps 1/8" I.D. Now, as I blast along well North of the century mark, a little voice tells me I may have starvation/lean issues due to that tiny tube. I haven't FELT any problem, but not sure as I would. The running out of power on the top end could be the leaning? I didn't photograph the little tube, can anyone check it out if you have one on the shelf?
These are them:
BAP petcock FLOW VOLUME question
 
The tap galleries are only approximately 1/8" diameter.

BAP petcock FLOW VOLUME question

BAP petcock FLOW VOLUME question


If you are concerned they do not provide enough flow then I suggest you measure their flow rates?

Or open both when at high speed.

Edit: If they are Stat-O-Seal washers in your photo then I suggest you insert a plain washer between each Stat-O-Seal and nut.
 
agree, if you are concerned with flow rate then as LAB indicates, open both taps.
I haven't measured the BAP flow rate either.
I can imagine the both of them open and how long it would take to drain the tank and just can't see anyone on a public road at WOT long enough to use more than that.
Isn't it tourist season up your way? They have only their best interest in mind so be careful.
I do know this about BAP taps: one may screw the sock down far enough to interfere with fuel flow by sealing off the top of the standpipe on the main tap. I've done it so having a full tank and the main open used up the fuel faster than it could be replenished, all during normal riding. Opening the reserve cured the starvation and for a short time I could not figure out the problem, but that was it.
All the best.
 
Been using and selling BAPs for many years, in fact was responsible for their introduction to the Andover Norton range. I run them on all my Commandos, including racebikes, no problem. Have you ever looked at the size of the hole in your main jet? More than twice that can't flow through on WOT, and the holes in the main jets are but a fraction of the hole in the tap.
 
I was slightly alarmed when I saw the tube you mention. But I have done unscientific road tests with one petcock and both petcocks open, full acceleration, pulling up a long hill. I can't tell any difference what-so-ever. Hardly a mythbuster but it satisfied my mind.

Russ
 
ZFD said:
Been using and selling BAPs for many years, in fact was responsible for their introduction to the Andover Norton range. I run them on all my Commandos, including racebikes, no problem. Have you ever looked at the size of the hole in your main jet? More than twice that can't flow through on WOT, and the holes in the main jets are but a fraction of the hole in the tap.
Click to expand...
Yes, thanks, I've been looking at main jets for 43 years.
 
AntrimMan said:
agree, if you are concerned with flow rate then as LAB indicates, open both taps.
I haven't measured the BAP flow rate either.
I can imagine the both of them open and how long it would take to drain the tank and just can't see anyone on a public road at WOT long enough to use more than that.
Isn't it tourist season up your way? They have only their best interest in mind so be careful.
I do know this about BAP taps: one may screw the sock down far enough to interfere with fuel flow by sealing off the top of the standpipe on the main tap. I've done it so having a full tank and the main open used up the fuel faster than it could be replenished, all during normal riding. Opening the reserve cured the starvation and for a short time I could not figure out the problem, but that was it.
All the best.
Click to expand...

Opening both taps is a great idea, kinda defeats the purpose of a reserve function, and with no trip odometer, I'll be walking.

Thanks for your opinions on public roads and throttle settings. Tourist season? yeah, I guess. Welcome. Enjoy.

You mean the screen sealed off the top of the stand pipe?
 
rvich said:
I was slightly alarmed when I saw the tube you mention. But I have done unscientific road tests with one petcock and both petcocks open, full acceleration, pulling up a long hill. I can't tell any difference what-so-ever. Hardly a mythbuster but it satisfied my mind.

Russ
Click to expand...


Cool. That's good news!
 
L.A.B. said:
The tap galleries are only approximately 1/8" diameter.

BAP petcock FLOW VOLUME question

BAP petcock FLOW VOLUME question


If you are concerned they do not provide enough flow then I suggest you measure their flow rates?

Or open both when at high speed.

Edit: If they are Stat-O-Seal washers in your photo then I suggest you insert a plain washer between each Stat-O-Seal and nut.
Click to expand...

What flow rate would I look for? I used the Loctite PST on the BSPT and they sealed absolutely. Those washers are great... but not for this purpose.
 
Regarding flow rate...let's suppose you were running at 100 MPH with fuel consumption of 30 miles per gallon. You would be burning 3.3 gallons per hour. You would be burning 7 ounce per minute. My guess is you are probably getting better mileage than that, but lets hope it isn't worse!
 
Yes, the inlet pipe on the main tap is 1/8" ID.
All fuel passages are measured at 1/8" ID.

The BAP taps are nice, the tall filter screen tubes unscrew for cleaning.
BAP petcock FLOW VOLUME question
 
concours said:
Opening both taps is a great idea, kinda defeats the purpose of a reserve function, and with no trip odometer, I'll be walking.

Thanks for your opinions on public roads and throttle settings. Tourist season? yeah, I guess. Welcome. Enjoy.

You mean the screen sealed off the top of the stand pipe?
Click to expand...

If you look at your original photo's you may notice the plastic caps at the top of the sock (strainer).
That's what I meant. It should be obvious that a screen wouldn't block off a stand pipe, even to you.
I don't get the sarcasm, don't need it either as I easily have enough for both of us. Ride fast and be careless.
All the best.
 
concours said:
I used the Loctite PST on the BSPT and they sealed absolutely.
Click to expand...

The tap/tank thread is parallel 1/4 BSP (BSPP), and not tapered thread BSPT.

concours said:
Those washers are great... but not for this purpose.
Click to expand...

I've used plenty of them and found the washers to be excellent if they are uniformly compressed (although personally, I prefer the copper jacket sealing washers).
 
Not to worry. My BAP petcocks each flow more than 20 fluid oz per minute, more than enough to support 60 HP. The constriction in fluid flow lies in my Mikuni VM34, not in the petcocks.
 
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