Hammerswinger
MEMBER
- Joined
- May 2024
- Messages
- 11
Hey all, Im getting new petcocks for my '74 Commando. Are the thread sizes 1/4" on both ends?
Cheers, Joe
Cheers, Joe
Petcock Sizes
- Thread starter Hammerswinger
- Start date
I have had nothing but failure with the blade type petcocks.
One year after, they will slowly drip fuel into the carb circuit.
The reserve tap did not do that as I hardly used it but the main did.
I found that out when I took the tank off and stored it flat and found a puddle
under the main petcock.
I replaced it and months later. same thing
I have converted both to the below style but it has only been
4 months so I cannot report if they are any better
Dennis
One year after, they will slowly drip fuel into the carb circuit.
The reserve tap did not do that as I hardly used it but the main did.
I found that out when I took the tank off and stored it flat and found a puddle
under the main petcock.
I replaced it and months later. same thing
I have converted both to the below style but it has only been
4 months so I cannot report if they are any better
Dennis
Torontonian
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- Dec 2009
- Messages
- 5,746
Bap are the way to go . Fragile blade type only for shows .
concours
FULL MEMBER
- Joined
- Dec 2011
- Messages
- 10,679
As stated below, they are 1/4" BSP. Be sure you understand the nomenclature. British Standard Pipe. It is not the NPT, (National Pipe Thread) which is so readily available here in the US. Just be aware. If you already knew this, then carry on. In the industrial world, I see this continually…
NPT vs BSP Threads: Key Differences, Applications, and Compatibility Guide
Learn the critical differences between NPT and BSP threads, including design, sealing methods, and applications. Discover best practices and how to choose the right thread type for your project.
www.titanfittings.com
Last edited:
Deets55
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- Oct 2013
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- 1,704
Since my BAPs have a nut that will run the whole length of the threaded section on the tank side wouldn’t that make them a BSPP? Or are there different variants for certain year bikes. Both my Roadster and Interstate tanks are 1975 and use straight threads.
concours
FULL MEMBER
- Joined
- Dec 2011
- Messages
- 10,679
On is up, the handle is parallel with the flow.
With the handle perpendicular to the flow is off.
Last edited:
Elfix
FULL MEMBER
- Joined
- Mar 2020
- Messages
- 144
I’ve had very good luck with the tapered cone style petcocks if they are taken apart, cleaned, and lubed with this stuff:
www.aircraftspruce.com
EZ Turn ( Fuelube ) 1 Lb Can | Aircraft Spruce ®
EZ Turn ( Fuelube ) 1 Lb Can EZ Turn is a specialty lubricant/sealant used for fuel and oil line valves & is resistant to high temps. Especially effective where high octane fuels and aromatics are present. EZ Turn is also e...
www.aircraftspruce.com
