99 zx9r problems : Kawasaki ZX Forums: Kawasaki Ninja Forum

dl1477 · 06-16-2008, 07:19 AM

I am having acceleration problems on my 99 zx9r. The bike accelerates fine up to 5000rpms, as soon as it its 5000rpms the bike bogs out and will not accelerate anymore. I can hold the throttle down at 5000rpm and the bike spits, pops and sometimes maintains speed, but most of the time the bike slows down. I can come to a complete stop and takeoff again, and it will run fine until 5000rpms. This problem is occurring in every gear. I can pull the clutch in and rev it to redline, but once there is a load on the bike it will not go past 5000rpm.

Any suggestions on where to start, or has anyone else ever experienced this?

Thanks
Dan

imjester77 · 06-25-2008, 06:42 PM

sounds like your carbs are running low. the fuel pump catches up and you are fine. if you sit and rev the engine you do not use as much fuel as you would think. not enough to put a strain on the fuel pump. I am not saying it is the fuel pump, but it is definatley sounding like a fuel supply problem.

did you change the plugs yet?

dl1477 · 06-26-2008, 11:19 AM

yes i have changed the plugs, and cleaned the air filter. I was thinking of taking the carbs off and cleaning them, but i have never done that before. The mechanic at the bike shop said it would be around $600 dollars for them to do it. I have cleaned the carbs on my car before, so i figure i will get it a shot. i guess i will go check the fuel pump before i go through that though. Is there a way to check the fuel pump?

imjester77 · 06-26-2008, 02:26 PM

yes. It is not really that hard either. the things that you will need are a gas can (empty or not full), and a long fuel line for the feed fuel to the gas can. hook the long line to the outlet on the fuel pump and feed it to the gas can.
Next you need to bypass the relay to isolate the pump. the relay is under the passengers seat cowl. there are 4 wires going to it. You need 2. One red and the other Blue. I used a paper clip. jump the leads to make contact. put the bike in nuetral and turn the key on and put the kill switch to run. You do not need to try and start it at this time. listen for the pump and see if it pushes fuel. If it does not turn on and pump fuel, it is bad. Also if you do not have a fuel line just hanging around, any line will work. it is out going not feeding so there will not be any suction. also the pump is relatively low volume so it wont pump like crazy. Good Luck

PS. if the main jets are clogged, you will need to tear down the carbs. But for the time being, you can spend $5 and buy Sea Foam at any auto parts store. This stuff is great. Worked miracles on my carbs.

BrianJohnson · 07-22-2008, 08:46 PM

Definitely make sure that you don't have a crack in the air filter foam that is separating under higher trottling.

dirty13south · 07-22-2008, 10:27 PM

Sound like ether a fuel problem OR a vaccum problem While you taking everything off anyway to do the carbs check you vaccum lines to. The one on top and the ones under the intake just under the carbs.

ALSO check the connection to the ram air under the front fairing there is a little Y valve that is accually an air filter pull off the lines and clean it out.

NORTHEASTCYCLE · 07-23-2008, 04:10 AM

I Had The Same Bike When It Happen To Me I Found The Vaccum Dieafram In The Carbs Bad The Wear Out From What I Had Found Out I Went On Ebay And Found A Set Of Rebuilt Carbs For Like $200.00 Shipped After Replacing Them The Bike Ran Better Then It Ever Had If You Need A Core I Have My Old Set Of Carbs Still Good Luck