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That system doesn't appear to be an emissions system exactly... it is a venting system that appears to have gas in the vent. The gas in the vent hits the separator gizmo and is returned to the tank. The air is coming in from the cannister to vent the tank.

The reason a tank is vented is to ensure a vacuum lock doesn't set up in the tank. If this bike were mine, I would first plug the vent hoses or outlet to the vent hose and see if the cap vents the tank as is normal. The cap appears to be the same type as on my 79 and 80 KZ1000E shaft bikes but it is hard to tell. These caps are retained by two 5mm phillips screws and have a large rubber seal that contacts the lip on the tank to keep them from leaking. To check to see if the cap vents, block the vent under the tank and the return with rubber caps and see if gas still flows normally.

If it does, plug them permanently and get rid of that separator thing and the cannister before it causes a fire. If not, install a venting gas cap... I believe it can be done fairly easily if you weld in a new bung for a Harley style screw in cap that vents then you won't have to worry about that junk with the hoses, separators and cannisters. That is truly a strange way of dealing with venting.

there might be something here that helps. it's for a 1984 gpz550, but i imagine a lot of early emissions systems worked the same way.

kzrider.com/component/option,com_joomlab...id,3/id,94292/#94292

it looks like the sealed gas tanks came in around 1984.

the gas tank is vented to the atmosphere through the charcoal canister. if the tank tubing is blocked or the canister is saturated with fuel, there will be a vacuum in the tank which stops the gas from feeding the engine.

the link also has instructions on how to remove the emissions tubing (where to cap/vent/etc).

(the purpose of the charcoal canister is to absorb gasoline fumes from the tank while the bike is parked. when the engine is started the fumes are sucked into the engine and burned up. all our cars have exactly the same setup. if you block off all the tank connections you have to install a vented gas cap or, if possible, find a way of safely leaving one of the tank tubes vented to air.)

The cap does appear to be sealed, so I'll have to look into fabing in a vented cap. Thanks for all the help guys, you all rock!

If it's the OEM cap, it is NOT sealed.

Directly in the middle of the two bracket mounting screws is a rubber fitted vent hole, and on the cap itself is a hollow "nipple" that vents the tank to the outside world.

www.kawasaki.com includes this warning:

'NOTE: Even if you did not purchase your vehicle in California, you may have a California (CA) Spec model. To ensure that you are able to select the correct parts for your vehicle, you must know whether your vehicle is a California (CA) spec or 49-State (US) spec model. Look at your warranty registration card; if the model code ends with 'L' you have a California spec vehicle. To go directly to the correct parts list for your vehicle, you may enter your Vehicle Identification Number on the Vehicle Information screen.'

funny thing is the 'L' and 'non L' gas caps have the same part number. so much for that theory...

but it's easy enuff to check. just take the bike out for a run with the gas cap slightly open. if it's still bogging, i got nothin'.

Jae,

The biggest problem with these types of systems is, after sitting for some time with fuel in them the fuel goes bad and clogs everything up.
The hoses are easy enough to replace, but it's the hard components (cannister, seperator and metal lines running from the lower rear of the fuel tank) that present flooding and venting issues.

My bike was left sitting by it's PO for 8+ years with fuel in it. And I found that the lines from the rear of the tank were so gummed up inside that it took repeatedly spraying carb cleaner into them, running a thick but flexible wire through them, and then blowing them out with my air compressor to finally be able to free it all up.
You should have seen the globs of crap that flew out of them when the largest portions of the clogs broke free and plastered themselves to my garage wall!

If you want some pics and details of how I removed all of the emission stuff and re-routed or capped the appropriate hoses on my ZN700, just shoot me a PM with your email addy and I'll get them to you.

Post edited by: RetroRiceRocketRider, at: 2007/04/08 17:28