I brought Home my '77 KZ650 *VIDEO AND PICS*

kevski wrote: previous owner has attached a vacuum pipe to number one carb inlet stub there is nothing wrong with this set up, Zephyrs are done the same way, ........

One problem with that home-made vacuum solution is that it introduces the possibility for leakage of air or fuel into the carb holder. If that happens the bike will run poorly since the #1 cylinder will run lean or rich. One way to test for leakage is to remove the vacuum hose from the carb holder and see if there is any sign that fuel has come through that hose. The hose should show no signs of fuel. Also, if you temporarily cap off the vacuum nipple on that carb with the appropriate rubber plug and set the petcock to “Prime” you should be able to start the bike and see if it idles better. If it does there was leakage; if not there was no leakage. Ed

650ed wrote:

kevski wrote: previous owner has attached a vacuum pipe to number one carb inlet stub there is nothing wrong with this set up, Zephyrs are done the same way, ........

One problem with that home-made vacuum solution is that it introduces the possibility for leakage of air or fuel into the carb holder. If that happens the bike will run poorly since the #1 cylinder will run lean or rich. One way to test for leakage is to remove the vacuum hose from the carb holder and see if there is any sign that fuel has come through that hose. The hose should show no signs of fuel. Also, if you temporarily cap off the vacuum nipple on that carb with the appropriate rubber plug and set the petcock to “Prime” you should be able to start the bike and see if it idles better. If it does there was leakage; if not there was no leakage. Ed

It's no different to the factory way of doing it, which can also be subject to the same problems, like i said the zephyrs are rigged up in the same fashion.

kevski wrote:

650ed wrote:

kevski wrote: previous owner has attached a vacuum pipe to number one carb inlet stub there is nothing wrong with this set up, Zephyrs are done the same way, ........

One problem with that home-made vacuum solution is that it introduces the possibility for leakage of air or fuel into the carb holder. If that happens the bike will run poorly since the #1 cylinder will run lean or rich. One way to test for leakage is to remove the vacuum hose from the carb holder and see if there is any sign that fuel has come through that hose. The hose should show no signs of fuel. Also, if you temporarily cap off the vacuum nipple on that carb with the appropriate rubber plug and set the petcock to “Prime” you should be able to start the bike and see if it idles better. If it does there was leakage; if not there was no leakage. Ed

It's no different to the factory way of doing it, which can also be subject to the same problems, like i said the zephyrs are rigged up in the same fashion.

Do you have a link to a diagram that shows a vacuum line from the petcock attached to a carb holder on a Zephyr? I looked at the parts diagrams for 3 different Zephyr models and could not find any that show a vacuum nipple on the carb holders (see links below). I’m not saying you are wrong, I am just curious about why the diagrams do not show it. Ed

www.powersportswarehouse.com/p/Kawasaki#...1-1991/C14C1446E1111

www.powersportswarehouse.com/p/Kawasaki#...-1995/C15C1523E11113

www.powersportswarehouse.com/p/Kawasaki#...-1992/C14C1424E11112

I have described it wrong, the vac stubs for the zephyrs are on the carb throat at the inlet stub end, the ones that are actually in the carb rubbers are on my XS650, my mistake for mixing it up, my Kz1000 also has the vac take off on the carb throat, but regardless of whether it's on the carb throat or on the inlet stub the outcome of any failures as described in your earlier post will be exactly the same, diaphragm failure poor running, carbs overflowing, petrol possibly filling crankcase and or floor covered in petrol, Vac pipe split poor running and only on 3 cylinders. all of these will occur regardless of where the stub is on the inlet tract. Though if it were mine i would change the petcock back to a manual one and as i am not bothered about originality a Pingel one it would be

Ed. Here are photos of my carbs setup. As you can see the vacuum valve from the petcock goes....somewhere. Not sure if this is all stock?

Petcock is not stock, you should have non vacuum type, the brass stub on carb is a breather and normally there are two of these one for each pair of carbs with a hose that goes rearwards towards the air box, if you have 3 carbs with the brass stubs 1 of them would be a vacuum stub, but as it is your set up works unless you want the stock tap you have nothing to worry about, and if you want a stock tap you just have to put a bung over the manifold stub.

kevski wrote: Petcock is not stock, you should have non vacuum type, the brass stub on carb is a breather and normally there are two of these one for each pair of carbs with a hose that goes rearwards towards the air box, if you have 3 carbs with the brass stubs 1 of them would be a vacuum stub, but as it is your set up works unless you want the stock tap you have nothing to worry about, and if you want a stock tap you just have to put a bung over the manifold stub.

Im not sure what all that means but Ive posted pics of my carbs set up for ppl to review

Your carbs appear to be the original Mikuni VM24SS units supplied with the bike. They do not appear to have the vacuum nipple – this is normal for the 1977 KZ650 carbs.

The brass nipples that are located on the top of carbs #2 and #4 are vents. They allow air to escape from the carb bowls as the bowls fill with fuel. They should have hoses on them, and the other ends of the hoses should be routed toward the air box and not be plugged or attached to anything. They need to let the carb bowls breathe to the atmosphere.

It looks like you have a vacuum operated petcock; as kevski pointed out that is not stock. Assuming that is true, the vacuum line from it must be connected to a source of vacuum when the engine is running; otherwise a correctly functioning vacuum operated petcock will not deliver fuel if it is set to the RUN position. If you wish, you can attach it to a vacuum nipple on a carb holder as is shown in kevski’s photo. Personally, I would just buy a non-vacuum petcock similar to that which the bike came with – but that’s just the way I am. Ed

650ed wrote: Your carbs appear to be the original Mikuni VM24SS units supplied with the bike. They do not appear to have the vacuum nipple – this is normal for the 1977 KZ650 carbs.

The brass nipples that are located on the top of carbs #2 and #4 are vents. They allow air to escape from the carb bowls as the bowls fill with fuel. They should have hoses on them, and the other ends of the hoses should be routed toward the air box and not be plugged or attached to anything. They need to let the carb bowls breathe to the atmosphere.

It looks like you have a vacuum operated petcock; as kevski pointed out that is not stock. Assuming that is true, the vacuum line from it must be connected to a source of vacuum when the engine is running; otherwise a correctly functioning vacuum operated petcock will not deliver fuel if it is set to the RUN position. If you wish, you can attach it to a vacuum nipple on a carb holder as is shown in kevski’s photo. Personally, I would just buy a non-vacuum petcock similar to that which the bike came with – but that’s just the way I am. Ed

Well Ed, Im the way you are! Wanting to replace the non-stock petcock. Where can I get it?

1977 had the manual petcock, but to use the vacuum one hooking to any of the 4 vaccum sync ports on the intake rubbers works just fine. Your bike is closely related to my 650 in the avatar it seems. Even the same wheels.

The original 1977 petcocks turn up on eBay sometimes, but not very often, so it may take a while before you find one. Pingel sells manual petcocks, but you need to make sure the holes for fastening it and the direction of the outlet are correct for your bike. Also, you may need to use an adapter plate. Ed

I have always had a vacuum style petcock on my 78 and I like it, they are safer then a manual unless you are real good at remembering to turn off your gas every time.

3 years ago I switched to a carb that was older and did not have a vacuum port so I hooked it up to one of the manifold vacuum ports and it works fine.

Ed is right about those being vents so they will not work.

Also the ethanol in the gas seems to mess with the rubber seal in the selector so I don't like to switch it a lot even into reserve.