Topic: Petcock upgrade for 73 750 gas tank

[70CB750]

The title says it all, since I am piecing the bike together - to make it reliable and easy to maintain - I would not mind changing the old style petcock to some newer version.

Anybody done it?  I would make an adapter to bolt on the tank with a bunk and the new petcock would screw on the adapter.

[bjbuchanan]

Only thing is how low it could hang. A good setup would have it up high, if it gets a bit lower from the adapter it would hit the carb rack

[70CB750]

Only thing is how low it could hang. A good setup would have it up high, if it gets a bit lower from the adapter it would hit the carb rack

Yep, I walked to the parking lot to check it out and that seems to be the most limiting factor. 

[Old Scrambler]

2 fuel-lines are required and at the measured flow from the stock petcock. If you change the rate of flow........your asking for trouble. The stock unit is basically the same as used on the CL72 beginning in 1962.  It worked well for new production bikes to 1976.  Miy K3 unit still works like it should and has yet to be rebuilt. Units and parts are readily available.

[754]

One word...
 PINGEL

[MCRider]

2 fuel-lines are required and at the measured flow from the stock petcock. If you change the rate of flow........your asking for trouble. The stock unit is basically the same as used on the CL72 beginning in 1962.  It worked well for new production bikes to 1976.  Miy K3 unit still works like it should and has yet to be rebuilt. Units and parts are readily available.

I don't think the 2 line v the 1 line makes any difference Dennis. The original 2 line cock was replaced with a 1 line cock on essentially the same bike, CB750K. Around K4 I think.

[Old Scrambler]

I like PINGEL............made in Wisconsin..............and they flow very well.  MC.......Your almost right (better than my off-handed statement "to 1976"). K5 they moved to the left side and single line.........but I think larger diameter...............   

[strynboen]

my cbx 1000 1978... 105 hk use a small 1 line petcock...so think not it give problems .....

[MCRider]

I like PINGEL............made in Wisconsin..............and they flow very well.  MC.......Your almost right (better than my off-handed statement "to 1976"). K5 they moved to the left side and single line.........but I think larger diameter...............

Nope, same size. Always 5.5mm.

[Airborne 82nd]

I like PINGEL............made in Wisconsin..............and they flow very well.  MC.......Your almost right (better than my off-handed statement "to 1976"). K5 they moved to the left side and single line.........but I think larger diameter...............

Nope, same size. Always 5.5mm.

Not mine stock 78 750K valve ID is 3.45mm measured 3 times most likely should be 3.5mm. Now the fuel line is 5.5mm ID has to be to go over the valve extra tight.

[Whaleman]

Check out my internal filter in the tips and tricks section under Carbs. Dan

[kball]

Whats wrong with the stock petcock?

[neilc]

Pic for Dan

[754]

I think a brass ball valve would cleaner.... How much reserve is that. 6 tablespoons?

[vames]

Pingel makes adapters. You just have to drill holes to match the screw spacing on your tank. (Or you could pretty easily copy this design).





http://www.dimecitycycles.com/vintage-caferacer-cafe-racer-bobber-brat-chopper-custom-motorcycle-carburetor-fuel-tank-parts-pingel-universal-petcock-adapter-nut-49-7738.html

[70CB750]

Thanks guys, very helpful.

The tank I have is somewhat bent around the petcock mounting holes and i am afraid the stock petcock will not seal against it.