Leaky tubes?

Hey all,
this is my first post here and I'm a bit new to bikes in general. I have never had to work on motorcycles before so I'm not sure exactly what I am looking at.

I just bought this bike for $650 and it's so much fun. A 1977 KZ750

I parked it overnight and I realized that a puddle formed under it smelling like gas. So I found some tubes that were just leaking gas from what I assume is the carburator. I would say it was 1drop/ 30 seconds. I don't know what the tubes are for or where they should go.

I'm happy to learn though if you would be so kind

here are some photos:

Untitled by Project Nate , on Flickr

Untitled by Project Nate , on Flickr

Those tubes are the Float Bowl overflow vents. The Petcock, was it shut off? Also looks like the bowl gasket is leaking. The float levels are either to high from leaking needle and seats on float valve, or miss adjustment. Is there a good In-Line filter? If not Crud could be in the float Valves. But really looks like a good cleaning and carb kits, with setting them up on the bench then following through with tuning is in order.

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MNateo wrote: Hey all,
this is my first post here and I'm a bit new to bikes in general. I have never had to work on motorcycles before so I'm not sure exactly what I am looking at.

I just bought this bike for $650 and it's so much fun. A 1977 KZ750

I parked it overnight and I realized that a puddle formed under it smelling like gas. So I found some tubes that were just leaking gas from what I assume is the carburator. I would say it was 1drop/ 30 seconds. I don't know what the tubes are for or where they should go.

I'm happy to learn though if you would be so kind

here are some photos:

Untitled by Project Nate , on Flickr

Untitled by Project Nate , on Flickr

Hello, MNateo, and WELCOME to KZr!

Obtaining a genuine official Kawasaki service manual should be a high priority.

Would monitor ebay for examples such as these:





Good Fortune!

Everything Motor Head advised and suggested, but would also add: check that the overflow tubes are not cracked first(its not clear if you meant to say both carbs are leaking). It sounded from your post that the bike is running well. I gathered this from your quote about it being so much fun. So, if the overflow tubes are the culprit, then I would just do a repair and keep on riding. Here is an example of overflow tube having a vertical crack.







You can check for this once you take the bowl off visually to see iff it is visible. Otherwise, by filling the bowl 3/4 of the way with fuel. If fuel drips out from the bottom the tube, then you have a leak. If the tubes check out as good, you should continue with a carb cleaning / rebuild as has been suggested. If the tube(s) are damaged, you can make a repair and continue ridding.

wow guys, Thanks so much for the quick responses! I was worried since the bikes were older, the board wouldn't be very active. I was pleasantly wrong! The bike does run quite well. It tries to hold it's RPM at 3K when coming to a stop, but simmers down eventually at a stop (3-7 seconds) I'm guessing that also probably has something to do with gunked up carbs.

Should I wait to take stuff apart till the kits gets here?

I'm guessing this would do the trick:
www.oldbikebarn.com/Kawasaki-KZ650-KZ750-Carb-Kit

Also, I I'll also buy book.

Taking along time to reach idle and be a couple of things. Looking at those carbs, they are needing TLC. But also you may have cracked leaking Intake manifolds/ carb holders. I might be a good Idea to look at the bike really good and do one order if you can afford it. New boots from the Airbox to the carbs will help you get them in & Out.
The Ignition has a mechanical advancer that requires periodic lubrication, in the right cover at crankshaft end. If it is slow returning it will also give the symptoms you've mentioned.
Z1enterprises has the stuff for your bike also.
I would get some filters, oil/ air/ fuel, and some fork oil, brake pads, etc. What ever looks like needs changing. Saves on freight.

MNateo wrote: I'm guessing this would do the trick:
www.oldbikebarn.com/Kawasaki-KZ650-KZ750-Carb-Kit

Also, I I'll also buy book.

Those carb kits on the old bike barn site They are for 4 cylinder bikes.
Try these from Z1 Enterprises but double check first as I am not familiar with the 750 twin
www.z1enterprises.com/Carburetor-Rebuild...er-19761978-299.aspx

Do I need 2 of these kits? It seams like it only has the stuff for 1 carb

Last bump I swear ! I ordered 2 rebuild kits, so hopefully I'll be able to get everything taken apart and put back together while Irene is outside so I don't waste days, when I could be riding! I'll be sure to take lots of photos and maybe a video to help other newbs like me.

The carbs are off the bike, the parts are in the mail, and the service manual is on my computer as a PDF. I started to take apart the carb a little to see if there was any leaky drain needles. I filled both bowls up with water to the brim of the bowl, and there was no leak:
I filled them with water and left them above the sink to see if they leaked. Is there any problem testing these things with water? Gasoline is not so great to have in your house..

Untitled by Project Nate , on Flickr


The next thing I looked at was if the Floats, Float. They do. So I moved on to the float needle.

Here is a closeup of the driver side(lol) float needle. They are both VERY similar as far as wear goes, but I could include a photo of both of them if you wanted. I don't know if these are worn or not simply from my lack of experience, but I'll let you all make the call.

Untitled by Project Nate , on Flickr

Finally I check the float needle seat. Again, very similar wear and I'm showing the one that was leaking 'more'

Untitled by Project Nate , on Flickr

For my last test, I put the drivers side carb together and filled it with water. It didn't leak and I don't think I could cram anymore liquid in there. Maybe I fixed it, just by opening it up and some piece of crap fell out?

So I don't really know what to do except replace the parts as each piece looks to be in decent condition. float level adjustment?

please advise

No problem using the water. Some people like using rubbing alcohol. Not sure it matters with regards to the fluid properties (surface tension and the like). If you had a problem with the overflow tubes or drain plugs, it would have been evident with your test. Your needles have seem better days, they could be the cause. Once done with your carb cleaning and rebuild. Bench test the float levels using the clear tube method. If test fails, keep adjusting/testing until proper float level is achived. Once you have a good level, you can bench test the carb assembly for leaks to see if you get any more drips prior to installing on the bike. Don't forget to bench sync.

+1 on the water and needles.
You'll probably get replacement needles in the rebuild kits. With the needle seats it's a good idea to run a Q tip soaked in carb cleaner around the seats when you are cleaning everything else. With dirty seats I have used Brasso to good efect when carb cleaner was not good enough.
Good luck.