Vacuum to manual petcock

I've got a 78 650 with the vacuum petcock.
Anyone successfuly modify it to manual?

I've capped off the fittings for vacuum but still get dribbles out of the petcock with fuel line disconnected.

Broke college kid can't afford pingel etc right now but am concerned about the dribble leaking into my engine (oil smells slightly fumey)

Thinking off installing manual cheap inline on off if all else fails

I would just clean and rebuild the factory petcock. The small oring may be the only expense. The oring may have deteriorated or there may be some schmuck on the seat it is supposed to seal against.
You can try this..... Ride the bike until the tank is almost empty. Remove the fuel tank. Hold the tank so that the fuel outlet is over a suitable container ( a piece if fuel line on the outlet may be needed), turn the lever to PRI and empty the tank. Put the tank on your workbench wit an old towel under it to prevent scratching and remove the four screws that hold the petcock together. Be very careful separating the two halves so that you do not tear the diaphragm. Replace the little oring and carefully clean the seat with a rag and a little carb cleaner. If it is not too bad, your bare finger may be good enough to clean it. DO NOT use anything more abrasive. Put it back together and check for drips and leaks.

There are 2 different vacuum petcocks they used in 1978. One of them, at least last time I checked, you could buy a new diaphram for like $14.00 through Kawasaki. The diaphram includes the sealing oring. I've done a few replacements and they all worked fine for me. The other petcock they used is completely different design and no parts available anywhere to work on it.
As to gas getting in the oil, there has always been worry of this, but the drain tubes on the float bowls prevent this. You'll get a puddle of gas on the floor, none in the oil. Believe me, in 300,000+ miles on 77-79 KZ650s and 1000s I've seen my fair share of gas puddles, but never once got gas in the oil. Some of the newer CV carbs may have this happen, not sure, but the old slide carbs not likely.

Right on fellas. I appreciate the help
I read various post for other bikes with vacuum petcocks, people will fill the inside vacuum port with a bolt or various things to make it a full manual petcock. Anyone modified one? I will probably just order a new cheap Chinese one eventually (manual petcock)

Ron, as for the oil in the gas , I guess I'm just paranoid cause I read you can destroy your engine and rings etc (I'm a worrier)
I just replaced carb bowl gaskets and stopped those leaks so I'm a little paranoid the leaks I can't see are going in the engine
Sounds like it would come out the vent before if would go into engine.

Thanks a bunch fellas now I can sleep lol!

If you want to use your current petcock manually, the only thing you have to do is remove the vacuum line and plug the vacuum port on the carb. Without vacuum, fuel will only flow when the lever is set to PRI. That will be used as ON. Every other position will be used as OFF. You will still need to have a good seal. That is also true of a true manual petcock.

What would be the benefits (and potential disadvantages) of a Pingel 6211 Power-Flo manual petcock vs. a stock vacuum unit?

www.pingelonline.com/motorcycle-fuel-valves/6211-ch.asp

Personally I prefer my stock manual petcock over the later vacuum operated ones. Since it has no diaphragm to fail it has proven to be extremely reliable. Having owned my bike for 40 years I have no problem remembering to turn it to the "OFF" position when I shut down the bike.

Regarding the Pingle manual petcock - it looks nice (I like shiny things), and I suspect because it doesn't use a vacuum operated diaphragm it probably would be more reliable than the stock vacuum operated unit. I believe you would need to use an adapter to fit it to your stock fuel tank. So overall I would say the price would be higher than a stock unit and you would sacrifice the stock appearance (if that matters to you). Ed

650ed wrote: Personally I prefer my stock manual petcock over the later vacuum operated ones. Since it has no diaphragm to fail it has proven to be extremely reliable. Having owned my bike for 40 years I have no problem remembering to turn it to the "OFF" position when I shut down the bike.

Regarding the Pingle manual petcock - it looks nice (I like shiny things), and I suspect because it doesn't use a vacuum operated diaphragm it probably would be more reliable than the stock vacuum operated unit. I believe you would need to use an adapter to fit it to your stock fuel tank. So overall I would say the price would be higher than a stock unit and you would sacrifice the stock appearance (if that matters to you). Ed

Speed thrills!:woohoo:

I picked up the Suzuki petcock from Z1 when mine went bad.... if I had it to do again I'd look for a manual one off Ebay and go through it(like Ed said) ......will do that someday for my spare tank if I ever get around to painting it and the spare panels.

The trouble with the Kawasaki manual petcock comes four ways for me. The first is the lever gets harder and harder to turn, and if not taken apart and greased on a regular basis, the lever will snap off. The other problem is despite the previous problem, the lever/hole wears and eventually the lever has tons of play and will leak between the lever and oring, even if the oring is new. Another problem is the oring will leak regularly even if the lever is not worn, and the leak is what ruins whatever lube you use to try to not get the snapped off lever mentioned previously. Lastly the rubber seal around the bottom of the petcock is always all deteriorated and leaks all over. I have like 20 petcocks and over the years used one to fix another, ect, ect. The vacuum is much superior. Just my opinion and experience. As long as you have the more common vacuum one, no reason to not just fix it. I see the diaphram is actually only $10.00 through Partzilla.com.

Have never had a vacuum petcock that was worth a damn....Those diaphragms might last a week or so,especially with the fuel blend that are being sold today
I have never seen a lever break off in over 40 yrs....This lend me to believe a lack of proper lubrication was not kept up with. if the oring is leaking there most likely is a nick or cut, if not I think the next size up oring will fit and stop any leaksge
I will never own a bike with a vacuum shut off petcock Turning it off is the same as putting down the kickstand

I guess everyone has their own experiences. I had the manual petcock on 5 or 6 different KZ650,900,1000 and every one had the same exact issues, where the vacuum works fine mostly. They got rid of that manual one after 1977 or so for good reason in my opinion. I'm sure they had multiple levers break, leaks ect, even when new, to decide to get rid of that fricking piece of dog crap.