I used to own a CBR600 2003 reg, but as I was not able to subdue myself and kept taking more and more risky chances, so I decided to sell up and downsize in an attempt to behave, which has worked a treat I must admit, more fun in the corners by a long stretch.

I used to own a NC30 years and years ago, but sold it for the CBR600, there was an obvious hike in power (nearly double). Now maybe it's just me but after having bought an NC29 and removed the restrictor kit the previous owner had installed (4 discs), the bike seems to pull very well upto circa 8K buit thereafter does not seem to pull at the same rate almost to the point of felling it's running lean? This really only appears after second gear, I have only gone upto 11K in any gear, but don't have any further pull, it really does feel lathargic after 8K, I was expecting a second wind or exponential pull?

I checked the restriction docs which only stated discs were installed to restrict the bike, so no mention of fuelling changes. Now is it just me being paranoid over the power reduction and expecting more for the 400cc? Or are other owners having a surge in power after 8K or so?

I would appeciate your comments.

I reckon it will have been rejetted and so is very lean.

Get it back to std and you'll be right

Thank you, I feel the same, will investigate. Believe the L model runs 108 main jet. Thank you.

How easy are the main jets to change please? Did it years ago back on my car...

easy..

carbs off, float bowls open, swap the jets.

might as well clean them up too..

Is it an hour job then?

Thank you

I reckon it cannot be too much more than that if you have some spannering skills and that all the screws n the float bowls don't fall apart when you point a screwdriver at them...

Cheers, do you need to remove the float pin and assembly to access the jets?

Thank you, I found the engine was running rich due to a loose emulsion tube on number 4. All fixed and very pleased. Thank you again.