Can anyone point me in a direction to get a new petcock for my AT1? My petcock leaks a lot when I turn it on. This is a replacement one I bought years ago that bolts up like stock but was from a different atv or motorcycle. What is everyone running now?

I’ve ordered 8 of these over the past several years and haven’t had any issues with them. Some folks shorten the intake tube to match the original tube length but I just use them right out of the box. The only effects are that you will need to switch over to reserve sooner than your original petcock if you don’t shorten the tube. The outlet tube goes out the side of the petcock which may be different than your original but it hasn’t caused me any grief.

imgur.com/a/yLej6Vu

That petcock Schu posted is the same one I have. I made the mistake of getting a cheap aftermarket one first, and it leaked horribly. I've had that one for the Yamaha Big Bear on my CT1 for almost 3 years now, and it works beautifully. I did shorten the tube to kind of match the original, but you don't have to.

The only other issue was the output on that petcock takes quarter inch fuel line, while your AT1 carburetor may take 5/16. I solved that by putting a inline filter in and have quarter inch going from it to the petcock, and 5/16 is going from the other side of the filter to the carburetor.

They can be stripped, cleaned and rebuilt.

There are a couple of versions of that part, but here is a link to CMSNL, and this shows both styles. The main rubber valve for both styles of tap are still available from Yamaha, probably through your local dealer.

Yamaha AT1C 1971 USA FUEL TANK - buy original FUEL TANK spares online