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zx7r ninja leans out with ram air installed

9603 Views 12 Replies 8 Participants Last post by  mscuddy
I have a 99 zx7r, It runs fine without my ram air installed. If I install the ram air tubes the zx7r starves for fuel and leans out fast. It will die if I rev too high.

I blew out the jets with 100psi air from my air compressor. I have a slipon yosh pipe. I dont know why its leaning out.
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Big Jets Needed

Beacuse you didn't PUT A FREEKING JET KIT IN...that consists of BIGGER JETS...to compensate for the increased AIR FLOW...after you put that dang Yoshi pipe on it...

DO that, (put a bigger jet kit in) and the problem should be solved. That, or put the stock pipe back on, see if it runs ok..and if it does, you'll know why.
Sometines....

Beacuse you didn't PUT A FREEKING JET KIT IN...that consists of BIGGER JETS...to compensate for the increased AIR FLOW...after you put that dang Yoshi pipe on it...

DO that, (put a bigger jet kit in) and the problem should be solved. That, or put the stock pipe back on, see if it runs ok..and if it does, you'll know why.
....ya just gotta take a breath. Hard to believe it but most people have no clue when it comes to exhaust/intake mods.... witness the high rate of loud bikes (cruisers and sportbikes) making like .38 Specials.
....ya just gotta take a breath. Hard to believe it but most people have no clue when it comes to exhaust/intake mods.... witness the high rate of loud bikes (cruisers and sportbikes) making like .38 Specials.
Breath in, breath out...
No you dont need bigger jets. The problem is the carb bowl vents need to be pressurized with the same pressure as the intake side of the carb. Your bowl vent tube iether fell off or is plugged. Did you take off the air diverter valve? If you did you need to redirect the bowl vent to the aircleaner.
No you dont need bigger jets. The problem is the carb bowl vents need to be pressurized with the same pressure as the intake side of the carb. Your bowl vent tube iether fell off or is plugged. Did you take off the air diverter valve? If you did you need to redirect the bowl vent to the aircleaner.
Exactly. John Burns had this exact problem in his recent article in Cycle World.
Good catch.

Exactly. John Burns had this exact problem in his recent article in Cycle World.
But with the mods he probably will need a jet kit anyhow. Bikes run pretty lean stock. He should at least do some runs to check the plug color.
None of us here really read Cycle World. We are all pretty much past that rag, so we certainly wouldn't know what old JB said. :lol:
?!?! Pressurize the float bowls? Wouldn't that cause the gasoline to shoot back into the gas tank and cause a horrible accident akin to the Hindenburg disaster? Oh the humanity...

Funny, but the ram air IV system on my '68 GTO (pirated from a '69) didn't have a pressurized float bowl..guess the Quadrajunk didn't need one...
?!?! Pressurize the float bowls? Wouldn't that cause the gasoline to shoot back into the gas tank and cause a horrible accident akin to the Hindenburg disaster? Oh the humanity...

Funny, but the ram air IV system on my '68 GTO (pirated from a '69) didn't have a pressurized float bowl..guess the Quadrajunk didn't need one...
Didn't they still use side valves and surface vapor carburetion in 1968?
I had a 4500 series Holly on my '69 Fury cop car with a 440 Interceptor with cop cams and factory duels. When you jumped on it it was like flushing a toilet with gas swirling down the intake.. the gas gage would head south while the speedo headed north accompanied by a nice Funny Car growl out of the Purple Hornies, That was a kick in the butt to race.
?!?! Pressurize the float bowls? Wouldn't that cause the gasoline to shoot back into the gas tank and cause a horrible accident akin to the Hindenburg disaster? Oh the humanity...

Funny, but the ram air IV system on my '68 GTO (pirated from a '69) didn't have a pressurized float bowl..guess the Quadrajunk didn't need one...
That's cause it had a FUEL PUMP!
Splain to me Loosie why pressurized float bowls wouldn't hinder the fuel filling up the float bowls unless the fuel was under pressure too. Don't make no sense 'tall.
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