Bike running lean after 7k

[ricethief]

Hi,

I recently took my bike to a track day after removing the airbox and fitting individual socks and now having trouble with a flatspot between 7k-10k and it will pull to redline after that. As far as I know the jets are standard and the bike has an aftermarket cam. Today i put a wideband oxy sensor on it and the results are at idle its 17:1, between 2k - 7k its around 12:1 and above 7k it leaned out to 20:1 after which I backed off. Besides changing the main jets what else do I need to do? What size jets should I be looking at going to? The bike is a nc23 tri arm.

Thanks

[tanuki]

Can ask why you are running a virtually open airbox?

[ricethief]

A couple of reasons, firstly not being able to get the box airfilter from the shelf where as i can get the uni filter socks here in oz, secondly there isnt any ram air on the nc23 so the box is just in the way for access to the parts below it.

[lizard821000]

and whats your jetting now

[ricethief]

I am guessing the 115 from the factory, i haven't open the carbs yet as i am wondering what others are running so i have an idea before i start.

[lizard821000]

so youv changed the airintake volume but not checked the jetting?? bit backward that mate. get the carbs open and check fella.

[Cammo]

A couple of reasons, firstly not being able to get the box airfilter from the shelf where as i can get the uni filter socks here in oz, secondly there isnt any ram air on the nc23 so the box is just in the way for access to the parts below it.

Short story is that your carbs weren't designed to work like you've set them up.

You can make them work in an open carb type setup (by restricting the air jet, bigger pilot jets, richer needles, richer emulsion tubes, bigger main jets and more) but it would be easier to put the airbox and filter back on.

If you simply install bigger main jets, the bike will still run like shit. Try it and see...

If you're stuck for parts you can get most by mail order from overseas.

[ricethief]

Thanks for the replies, i will just run the stock airbox again.