I have a 2000 ZR 600. When I take the airbox off I have a little fuel sitting in the bottom of the rubber boot that connects the airbox to the carbs. When I take the airbox off and run the engine in the shop I have a light fuel spray out of the carbs when I let off the throttle. My first instincts was reeds were bad so I put in new stock reeds, just the reeds not the cases and it still did it. It will get so much fuel built up in the air box that when I bust a big drift and it almost stops you dead that the fuel will go in to the carb and it will flood out for just a second and then take off again. I inspected the new reeds to make sure they were closing and they were. I also inspected the cages to make sure the sealing surface was fine. I don't know if I am totally missing something or what but I need help!!!!!

Oh the engine is pure stock.

Try checking your needle valve, cause it might be stuck open in ur carb.

Originally posted by ac_modder@Sep 7 2004, 12:22 AM
I have a 2000 ZR 600. When I take the airbox off I have a little fuel sitting in the bottom of the rubber boot that connects the airbox to the carbs. When I take the airbox off and run the engine in the shop I have a light fuel spray out of the carbs when I let off the throttle. My first instincts was reeds were bad so I put in new stock reeds, just the reeds not the cases and it still did it. It will get so much fuel built up in the air box that when I bust a big drift and it almost stops you dead that the fuel will go in to the carb and it will flood out for just a second and then take off again. I inspected the new reeds to make sure they were closing and they were. I also inspected the cages to make sure the sealing surface was fine. I don't know if I am totally missing something or what but I need help!!!!!

* * * * * * Oh the engine is pure stock.
343753

[SIZE=7][COLOR=red]
If you have allready gone through your carbs its time to rip into the fuel pump to check for a blown diaphram pump constant fuel to carbs.
you can pinch off fuel lines to carbs and see if condition goes away to verify bad pump

Spitback is normal on twostrokes and it's not ucommon to find signs of it in the airbox. I'd bet your bog is more clutching , jetting, related? are the carbs sync'd up good? airbox intact or gutted?

I agree with "pounder", spitback it normal on 2cycle. Check the clutching.

If this only happens when you find a big drift to break through, wouldn't you consider that it may be getting a big mouthfull of snow? Not familiar with the ZR, but I would check for good seal everywhere all the way out to air intakes. Probably wouldn't worry about it if it all checked out OK.

With any luck at all, the only thing you are missing is snow :D

Agree spit back is normal. To check fuel pump diapram, look for fuel in the pulse line. It should be dry. JMHO, but clutching and other issues would show up all the time. Not just when hitting a drift?

i had a sled that done the same thing as a smallengine tech i looked for some wear on the intake side of pistons this will give you that feul in intake most the time the wear will be on the skirt of the piston what happens is the blowby will throw fuel back the throuth of carb. just a hint use your own judgement hope this helped (with this prob there will not be a compression drop )

If it just happens in the deep drifts it may just be the exhaust getting blocked off, may need to build or buy a deflector?