Topic: Petcock size question

[bunghole]

I'm putting a '73 750K tank on my '77 750K.  I noticed that the petcock from the '77 won't fit the '73.  Does anyone know the size for the screw type petcock for the '73?  Also, I assume it is a single output petcock, no?

Thanks!

[bryanj]

73 should have the type held on with 2 screws inside the bowl

[bunghole]

Actually, now that I look back at its description from Ebay, it was advertised as a '73 750E.

Here is a pick:



It has a screw on petcock fitting that is larger (working off memory) than the one for the '77.

Thanks!

[bunghole]

I'm home and measured the petcock outlet and it is 3/4" or 19mm.  Anyone know if this is original or did someone modify the tank?  If original, anyone know a source for a replacement petcock that will fit?

Here's a pic of the outlet:



While we're at it, if anyone can definitively identify the year and model of the tank, that would help alot with tracking down a new cap gasket (no lock on cap if that helps).  Thanks!  Here some pics:

[bryanj]

All i can tell you is definately NOT 73. On the bottom oposite side to the threaded boss is a plate oval pad, if thats been welded on its been modded as thats where the original goes

[bunghole]

Huh.  Interesting.  Looks like it was originally a right side petcock that someone changed to work with a 3/4" petcock.  Fits the bike just fine, except for being shorter which is a non issue because I'm going to fab up some sort of cafe seat anyway.

So does anyone know what my options are for a petcock?  I don't need it to be Honda accurate, just leak-free with an on, reserve and off setting.

Thanks!

[SD750F]

My older CB750F3 Super Sport seams to have a 3/8" NPT... Or at least that is the only thing I can find that will fit. And yes, it is a tapered or NPT thread. I have heard that Honda did this for the 77 and 78 models, is that correct? So I am having a really fun time finding an after-market Pringel or other make for my project.

Any suggestions???

Scott

[chrislib]

pingel...nice but $$$

[Brantley]

My older CB750F3 Super Sport seams to have a 3/8" NPT... Or at least that is the only thing I can find that will fit. And yes, it is a tapered or NPT thread. I have heard that Honda did this for the 77 and 78 models, is that correct? So I am having a really fun time finding an after-market Pringel or other make for my project.

Any suggestions???

Scott

Huh.  Interesting.  Looks like it was originally a right side petcock that someone changed to work with a 3/4" petcock.  Fits the bike just fine, except for being shorter which is a non issue because I'm going to fab up some sort of cafe seat anyway.

So does anyone know what my options are for a petcock?  I don't need it to be Honda accurate, just leak-free with an on, reserve and off setting.

Thanks!
   

If you guys have a boneyard near you, look for a '75 or '76 CB500t. Those tanks have the same sort of external bung (pardon!), but I'm not sure of the size.

[754]

Just buy a 76 petcock for the black tank, or machine a fitting (20 min job) to fit what you got.

Pingel if I remember offered an adapter that would convert the 75 & down tanks.. it is easy to make but requires an o-ring groove

[bunghole]

Are the '76s 3/4"?  That's how big mine is.  My petcock I mean .

[Brantley]

Just measured the 500t. Approx 3/4" O.D. and 3/8" I.D. I would imagine the '76 750 is the same.

[bunghole]

That's great!  Thanks for the help everyone and especially Brantley for measuring his.

Off to find one!