Progression on strip down has revealed more missing parts. 1. Are connections from fuel pump critical? 2. Is it the flasher relay missing? Time to go find what else is in there or not.
Yes flasher box They have no fuel pump .... thats your vacuum system Ill take some measurements on that intake pipe tomorrow ... if I can find it
The top half of your airbox has a channel running down the middle of it. There is an air pipe sticking out towards the seat end. The vacuum valve can be bypassed by running the carb vents into a T piece and then running a hose to the airbox vent. The pipe at the bottom of the airbox (near the air inlet) is an oil drainage pipe and should normally have a piece of hose attached to it with a stopper at the end for draining any oil that is in the bottom of the airbox that has come from the Crankcase vent.
Thank you. I have none of the hoses connected or even loose need to source. What would be the best solution? Frankster's T mod.or get the 2 hoses. Thank you in advance.
I've never understood the function of the ZXR250C Vacuum Valve as it's not on the ZXR250A engines. The ZXR250A engine has the T piece configuration that I suggested as a workaround. The Vacuum Valve must use the 'draw' stroke from Cylinders 2 & 3 to create a vacuum for something. The fuel petcock is activated using the 'draw' stroke from cylinders 1 & 4. The hose to atmosphere isn't doing anything major as far as I can tell, so can someone please tell me why I shouldn't take all of that plumbing and hardware and throw it in the bin? A couple of rubber caps on the cylinder 2 & 3 vacuum tubes should seal that off nicely.
On the ZXR250A, the carb vents are routed directly to the airbox inlet that the Chief's image shows. On the ZXR250C, the carb vents takes a magical mystery tour through the Vacuum Valve and its associated plumbing. The airbox on both models is the same and you'd expect there is fresh and cool air in there for the carbs to suck in, so not sure why the ZXR250C Vacuum Valve is linked to the engine speed (vacuum from cylinders 2 & 3) to do whatever it does. It must have been designed to do something?
@Frankster maybe that vacuum valve is an early form of emissions compliance device. I am assuming when no vacuum applied the valve connects the float bowls to the air box. If so, it might be to feed vapour back into the airbox, rather than atmosphere, to be ingested by the engine when it next starts up. I have seen something similar done in cars. Or if the valve connects the float bowls to atmosphere on low/no vacuum then they might be trying to use the small depression in the airbox to tweak the mixture by pulling the fuel back into the bowl a little to lean it out under light load. Another emissions trick. Either way, for your purposes, just ditch it all and go for simplicity. Peter.
I have one at home somewhere. We'll sacrifice it to the 'discovery' gods when I'm back on the mainland. Once we figure out what's going on in there, then we should be able to confirm what the silly thing actually does. It's weird that nobody knows what it's function is. It's further weird that only Kawasaki went down this path and, from what I can tell, they only did it on the ZXR250C engine.
