Hi all
Right I have read many posts about pullling the breather hose from air box and either let it hang out bottom of bike or onto a catch tank, but what I want to know is if there is any benefit to not having the breather connected to the air box. My thoughts are that the dirty hot oily air will reduce efficiency and compromise power. My understanding has always been that closed loop breathing was purely to reduce emissions entering the atmosphere.
Ideas chaps, my nc23 hesitates at top end between 12-14k unless I roll the throttle on slowly to the stop
Dynojet 112, sponge air filter, std headers with Hyde can, 96db@8000rpm

I think the issue you're having is down to the exhaust being too restrictive rather than an issue with the airbox breather hose. Removing it will make no real difference to the performance other than allowing the bike to get covered in an oily film. the only time you would run the hose anywhere other than the airbox is if you've ditched the standard airbox in favour of the HRC carb tray (not recommended for a road bike).

MIght be worth getting the bike on the dyno for a tune up. I run a similar setup but have removed the foam from the filter element and have no issue with the bike revving out. Is the end of your exhaust quite black as I suspect you are running a bit rich.

Thanks for reply, yes the exhaust is black, the bike spends all it’s time on the track, the gearing is 14/42 so Revs quickly and now I’m able to use 6th, frustrating but I would expect a wide open throttle at top end would show a leaner mix! Because it runs so good from bottom up to 12000rpm, one thing I noticed is the bike is perfect for the first 3/4 laps then the hesitation starts

https://drive.google.com/open?id=0B9hUz ... jVCbGlPZUE

A photo

Funnily enough my track based 23 runs rich at full throttle too & I do need to get it out on the Dyno once the rebuilt engine goes in.
What is the front fairing on yours and how well did it fit?

A lot of work involved cutting and grinding, making new mounting brackets, bought off eBay unbranded fibreglass fairing, my advice would be buy the best one your budget allows . tail piece off 2006 CBR RR once again a lot of cutting and welding of subframe and mnsking mountings

https://drive.google.com/file/d/0B9hUzI ... p=drivesdk

https://drive.google.com/file/d/0B9hUzI ... p=drivesdk

Hi I'm from the Suzuki side of the fence, but I have no friends over there
You can sort the top end rich thing by increasing your MAJ by 0.1mm, and also leave your MJ where it is. That should cure your issue. If the bike splutters coming back on throttle then increase the MJ one size, and hopefully the top end will be OK.
Worked ok for my gsxr400 racer.
29mm inside diameter seems to be a ball park figure for race headers, finishing off to the usual 2" outlet.
You can also lean off the top end and gain a hp or 2 by removing the primary baffle which is usually hidden inside the collector. This will raise the db reading 2-3db, and will give your end can a slightly harder time, ie have to repack it more often.
The breather hose thing I would leave plumbed into the airbox, as it keeps the bike cleaner, and doesn't suck hp.

Good luck with it!

112 dynojet is probably too big with standard headers .


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