[Papasta]

Hi all, just a few days ago I pulled apart my ninja 250 carbies to give them a good clean and somehow lost 2 o'rings, one for the lean/rich adjustment screw, and one that sits in the diaphrahm, I bought some generic o'rings own of which fit ok but a little loose around the fuel adjuster, and for the diaphragm it protrudes from one casing and fits into the other so it's quite deep, for this I cut a bigger o'ring down, but didn't glue it, just fit it into the slot. The bike starts, but idles rough and when I give it throttle it jumps up in revs and doesn't return to idle, could these o'rings be my issue?

These are highlighted below with the yellow dots.

Thanks!

 

[SemiFast]

I give it throttle it jumps up in revs and doesn't return to idle, could these o'rings be my issue?

Yes.
The air cut off valve 'o' ring (at the diaphragm) needs to fit just right or you'll get air leaks around it and possibly at the diaphragm too. Leaking air there will make the bike do like you describe.
Also if the fuel mixture screw is not adjusted correctly or its 'o' ring is not sealing that could aggravate the situation or maybe even cause it.
Kawasaki sells the correct fuel screw 'o' ring and air cut off 'o' ring for the year model I looked up, 2010.

What year model is your bike?

S F

 

[Papasta]

Yes.
The air cut off valve 'o' ring (at the diaphragm) needs to fit just right or you'll get air leaks around it and possibly at the diaphragm too. Leaking air there will make the bike do like you describe.
Also if the fuel mixture screw is not adjusted correctly or its 'o' ring is not sealing that could aggravate the situation or maybe even cause it.
Kawasaki sells the correct fuel screw 'o' ring and air cut off 'o' ring for the year model I looked up, 2010.

What year model is your bike?

S F

Thanks for the reply! It's a 2009.

 

[SemiFast]

Well I was wrong. Kawasaki does not list the fuel screw 'o' ring separately for this model / year model.
But here is the part number for the correct size 'o' ring from Kawasaki: 92055-1078
Suzuki also sells them separately. Part number from Suzy: 13295-29900
Both are the same o ring. I always keep a supply on hand.

S F

 

[Papasta]

Well I was wrong. Kawasaki does not list the fuel screw 'o' ring separately for this model / year model.
But here is the part number for the correct size 'o' ring from Kawasaki: 92055-1078
Suzuki also sells them separately. Part number from Suzy: 13295-29900
Both are the same o ring. I always keep a supply on hand.

S F

Thanks alot for the reply and a huge thanks for the help!

 

[SemiFast]

Happy to help.

S F