Petcock Questions

I want to replace the single feed vaccuum petcock on my 1979 kz650 with a single feed gravity petcock. I know I need an adapter plate and a new petcock and I know I will probably need to round ot the hole in the gas tank in order to fit the new petcock in. Is there anything else that I will need to do in order to get the bike to run correctly or is petcock replacement as easy as it looks. Is there anything or any products I should be wary of? (I was going to order from Z1 because I have had great results from them.)

Please feel free to offer opinions on the best set-up.

Thank you guys in advance.

There are several aftermarket gravity feed petcocks avilable for the 650, lots of people favour the ones from Pingel, that´s probably what Jeff (Z1) will suggest too. You shouldn´t need to do any mods to the tank to fit it, but when you remove the vacuum line be sure to plug the stud on the intake manifold where the vacuum line attaches (stock is cyl. 2) or you´ll run lean on that cylinder. Easiest way to plug it is to get an extra cap like the ones on the other carb manifolds.

Post edited by: onkelb, at: 2006/01/14 12:21

It sounds like you know most of what you need to do the job.

DEFINITELY block off your vacuum port on the carb. Don't skip this step. You can buy an assortment of rubber caps at major auto chain retailers in the "Help!" section (which has all sorts of random things like that -- Help! is the brand name). It'll cost you $2-$3, and save you the cost of new pistons.

Read through Jeff's writeup on replacing your petcock -- he's done a very nice job of describing the issues involved.

I don't think paying for a Pingel is necessary unless you need insane flow rates. Even a high-displacement close-to-stock street bike should do fine with a "lesser" petcock.

As you mentioned, you might have to widen the tank opening slightly to accomodate the new one. It's easily accomplished with a Dremel or a file.

As far as I can tell, though, an adapter plate and new petcock should be all you need as long as you BLOCK OFF THE VACUUM PORT SO YOU DON'T HOLE A PISTON! (heh)

I put Jeff's petcock on both of my bikes and they work great. You do have to open the center with a dremmel to accomodate the wider and round tube, but it's not a big hassle and well worth the time to install the new one.