Missing overflow drain tubes?
- gte105u
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Missing overflow drain tubes?
26 May 2010 11:42
Please bear with me on what may be easy or stupid questions. I just bought a '81 KZ550 this past weekend. I have every intention on buying a shop manual but until I get one in the near future hoped you gurus may be able to help (I have a PDF version but the pics are very unclear... anyone has a good link to a clear version would be helpful as well). I am pretty sure this bike is missing the overflow drain tubes. I noticed it by finding a very small spot of fuel on the ground after I brought the bike home. I looked and do not see any tubes running from the bottom of the carbs. I have included 2 photos for someone to tell me if I am crazy or not. If they are missing, could this be causing the leak? Anyone got some good tips on what I need to get to replace, how to install, and how to route? I am in the process of doing a few smaller things (seat lock and center stand), and another pretty big thing (worn sprocket, so much it will not pass state inspection). Bike looks good, low miles (18k+), but has a few more issues than I originally thought. Thanks in advance.
1981 KZ550 A2
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- xLowEndx
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Re: Missing overflow drain tubes?
26 May 2010 11:49
I'm in the same boat as you with my bike, more issues than originally thought.
On my 750 those hoses go right into my air box and if I'm correct they are 1/4" tubes.
On my 750 those hoses go right into my air box and if I'm correct they are 1/4" tubes.
1980 Kawasaki KZ750-H1 LTD
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- JMKZHI
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Re: Missing overflow drain tubes?
26 May 2010 11:50 - 26 May 2010 11:54
Howdy. The bike should have overflow tubing. They're usually routed behind the engine & forward of the swingarm, away from the chain & mufflers, and hang down a few inches below the engine/swingarm. The leak won't have anything to do with those being missing, though. Kawasaki.com has diagrams in the owner info section. I find it easiest to use the Search-by-Model-Info without entering a vin or anything... just pick a year only, then choose a bike from the list. The diagrams show what size/length you need.
Last edit: 26 May 2010 11:54 by JMKZHI.
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- TeK9iNe
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Re: Missing overflow drain tubes?
26 May 2010 13:04
Correct JMKZH1...
The leak is being caused by an improperly seating float valve needle.
If the leak isnt too bad, get yourself a can of SeaFoam.
Dump the whole thing into a fresh tank of gas and run the old girl till its gone.
This can, and often does fix that problem, as well as clean things nicely inside your carbs.
The drain tubes SHOULD NOT be routed to your airbox. They are supposed to drain down completely away from all intake and combustion sources.
GL!
The leak is being caused by an improperly seating float valve needle.
If the leak isnt too bad, get yourself a can of SeaFoam.
Dump the whole thing into a fresh tank of gas and run the old girl till its gone.
This can, and often does fix that problem, as well as clean things nicely inside your carbs.
The drain tubes SHOULD NOT be routed to your airbox. They are supposed to drain down completely away from all intake and combustion sources.
GL!

Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors

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- xLowEndx
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Re: Missing overflow drain tubes?
26 May 2010 13:15 - 26 May 2010 13:23
TeK9iNe wrote:
Really? I have actual OEM grommets that go inside of my airbox that come out of the bottom of my carbs on my 1980 KZ750.
This isn't correct or am I just confusing the overflow tubes???
The drain tubes SHOULD NOT be routed to your airbox. They are supposed to drain down completely away from all intake and combustion sources.
GL!
Really? I have actual OEM grommets that go inside of my airbox that come out of the bottom of my carbs on my 1980 KZ750.
This isn't correct or am I just confusing the overflow tubes???
1980 Kawasaki KZ750-H1 LTD
Last edit: 26 May 2010 13:23 by xLowEndx.
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- gte105u
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Re: Missing overflow drain tubes?
26 May 2010 13:36
See this is why forums are the best... love the info. I pulled up the parts list, and see the hose as item 49
What does "3.5x550" mean? I am assuming that would be in millimeters? I looked up the part from Bike Bandit and would rather not pay the $20/pop it costs. Is this something I can get from the auto parts store, or do I need to pick up from a local cycle service? I will route down and out, and trim so it hangs down. Anything special I should know? I guess you can just have them hold in place with zip ties? I know I am full of annoying questions, but thanks all for the help.
I have seen several tips on the Sea Foam. The leak is not bad, overnight there is a very small spot on the floor. I will give it a shot, if not may try flushing to see if it helps.
What does "3.5x550" mean? I am assuming that would be in millimeters? I looked up the part from Bike Bandit and would rather not pay the $20/pop it costs. Is this something I can get from the auto parts store, or do I need to pick up from a local cycle service? I will route down and out, and trim so it hangs down. Anything special I should know? I guess you can just have them hold in place with zip ties? I know I am full of annoying questions, but thanks all for the help.
I have seen several tips on the Sea Foam. The leak is not bad, overnight there is a very small spot on the floor. I will give it a shot, if not may try flushing to see if it helps.
1981 KZ550 A2
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- Patton
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Re: Missing overflow drain tubes?
26 May 2010 14:26 - 26 May 2010 14:27
Any small rubber or plastic tubing that fits snugly onto the overflow nipples will be okay.
Here's routing on KZ900-B1 LTD. Loosely bundled together and routed behind engine to exit underneath bike.
Good Fortune!
Here's routing on KZ900-B1 LTD. Loosely bundled together and routed behind engine to exit underneath bike.
Good Fortune!

1973 Z1
KZ900 LTD
KZ900 LTD
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Last edit: 26 May 2010 14:27 by Patton.
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- H1Vindicator
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Last edit: 21 Feb 2013 01:49 by H1Vindicator.
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- JMKZHI
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Re: Missing overflow drain tubes?
26 May 2010 14:53
gte105u wrote:
Yep, that is mm. And yes, you can get the tubing from the auto parts store etc. - it's nothing special. Mine isn't zip-tied or anything - it seems to stay in place - it's a snug fit between the engine & swingarm.What does "3.5x550" mean? I am assuming that would be in millimeters? I looked up the part from Bike Bandit and would rather not pay the $20/pop it costs. Is this something I can get from the auto parts store, or do I need to pick up from a local cycle service? I will route down and out, and trim so it hangs down. Anything special I should know? I guess you can just have them hold in place with zip ties? ...
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- gte105u
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Re: Missing overflow drain tubes?
26 May 2010 15:18
Thanks for the info. I found 3.5 mm vacuum hose online for about a buck a foot, so I will probably pick up 8-10 feet. I may drop by O'Reilly to see what they have as well. Thanks for the help guys.
www.amazon.com/gp/product/B002S9Y0A2/ref...ie=UTF8&s=automotive
www.amazon.com/gp/product/B002S9Y0A2/ref...ie=UTF8&s=automotive
1981 KZ550 A2
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- DoubleDub
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Re: Missing overflow drain tubes?
26 May 2010 16:44
Stay away from clear line - I have used this in the past due to laziness and they get very hard, brittle, and eventually could plug. One of these days I'm going to change them out for something more fuel resistant....
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- gte105u
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Re: Missing overflow drain tubes?
26 May 2010 17:57
Ok so O'Reilly does not have metric only standard. Will 1/8" work?
I picked up a can of SeaFoam. Sales guy said it works great. Directions say to use one ounce per gallon of fuel. Will it help/hurt to use more? I was thinking of using half a can for two tank fills which is about double the directions. Thanks for the help guys.
I picked up a can of SeaFoam. Sales guy said it works great. Directions say to use one ounce per gallon of fuel. Will it help/hurt to use more? I was thinking of using half a can for two tank fills which is about double the directions. Thanks for the help guys.
1981 KZ550 A2
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