Topic: Where to find petcock seal. 78' 750F Supersport

[JJmoto]

Am looking for dimension or where to find a petcock seal, 78 750F. Style is threaded fitting onto tank with 90 degree outlet. This one is leaking real good and only has one sweet spot left in the off position where its holding and if you need to turn on reserve its really bleeding fuel out... . If anyone has info. for the dimension or part number from somewhere that would be awesome to not dismantle it first and have the o-ring on hand for fast swap!  Cheers! JJ

[754]

Do you know what it looks like ? I suspect a round disc with a few holes in it .

[samm_j2]

Perfect opportunity to upgrade to a pingel peacock. I just put one on my 78 cb750f

[JJmoto]

Trying to remember how to reply to the thread...so I was thinking you could be right...might be a solid rubber disc with selector holes, I havent taken it apart yet to see what it looks like and that Pingel petcock sure looks like a nice option if I can't repair the original which is going to happen soon...

[HondaMan]

Honda had 2 sizes of the 4-hole rubber (round) seal in the petcocks, the large one (up to 1976K models) and the small one (on the F2/3 and the K7, sometimes the K8) IF it is the petcock with a seal. Some have a tapered-seat valve instead, and if those leak they must be replaced.

Can you post a picture of yours?

Yours probably exits the valve toward the inside of the bike. I haven't seen those type in a while. There is another type available that will work, but needs a longer hose between the valve and the carbs because it exits toward the side of the petcock: it is #20-8037 at PartsNmore here:
https://www.partsnmore.com/parts/honda/cb750k/?filters[category]=air+%26+fuel&filters[fitting]=custom

[JJmoto]

Okay now thats great information Honda man! Thanks very much! I am thinking it would be the smaller size as its OEM 78' 750F with the exit to the inside going under the tank...I am certain there is some type of seal in behind it but Ive never seen one or a drawing anywheres...I have come across petcock that will fit but right or left exit and that would work but I would like to overcome the OEM issue and repair if possible....do you know if just the rubber 4 hole round seal is available from somewheres so I can keep the petcock factory style is preferred of course. That Pingel petcock might be the way...

[HondaMan]

The bigger one (K0-K6 dual-outlet and single-outlet petcocks, with filter grid & sediment bowl, outputs point down, is:
Honda #16955-268-020 (same as CB72/77)
PartsNmore #29-7028.

That's the one you DON'T want to use...just putting it here for other's reference.

[madmtnmotors]

The seal can be replaced:

https://www.partzilla.com/product/honda/16955-268-020?ref=9a5b1213b920bbd3a97a7ebe4674b3f02374a777

But, the fuel valve is riveted together so you have to carefully remove enough of the peened over rivet to be able to remove the faceplate but leave enough material that you can peen over a new shoulder upon reassembly. It can be done, I've done it, but since the petcock is riveted together you won't find this listed as a serviceable part for the later models.. Others have drilled the rivet post and tapped for machine screws. While you're at it I would suggest a new fuel filter which also happens to come with a new petcock to fuel tank seal:

https://www.partzilla.com/product/honda/16952-388-005?ref=cbfc5195024be899638c06086ef00a50d165a63c

[Don R]

 Do you want the one off my bike?
https://photos.app.goo.gl/CxJxgfdH7mGC19py5