Has anyone ever changed the needles on the carbs before to try and reduce any flat spots between 5000 - 7000 rev's. and can this be done on a road bike ?. and if so, where can i buy them. ?... Thanks again.

You don't need to change the needles,just put a 0.5mm thick washer under the head of the needles.

Yeah putting an extra 0.5mm washer (they already have 1 x 0.5mm standard) helps with the midrange, an aftermarket exhaust system (not just muffler) helps also.

The FI International nc30 carb needles have a good reputation, dynojet needles are dodgy.

+1

iv just been playing around with my bike, 2 and 2.5mm slides and 0.5 and 1mm needle spacing (one or two washers) best I found was 2mm slides and extra 0.5mm shim

my bike has standard system with a race can and a foam air filter and the 5k flat spot it had previously is gone now

Thanks again for this i will try a few things at the weekend, F1 International needles, do you know where i could obtain a set from ? Thanks Bryan ...

here is a tip.
try going down a breakers who if they are in a good mood,may let you take out needles from various honda's carbs.
i have got cbr400 needles in my vfr750 and they are the same length but have a fractionally better shape to give me more midrange.you wil need either a good eye or a vernier to check properly(got both luckily!),but its worked a treat and if i ever get the time to play around with jetting and needle height etc then it will get better again.
if you find something in the breakers then just say you found nothing(unless the carbs are really cheap.)then find the right forum and post an ad.

cabey wrote:Thanks again for this i will try a few things at the weekend, F1 International needles, do you know where i could obtain a set from ? Thanks Bryan ...

I'm not too sure whether they still make then Bryan. Try putting a wanted ad in the for sale section, some might turn up.

It's worth trying an extra washer under the standard needles before spending your hard earned.

Thanks again, i will take your advice and try an extra washer, and see how that goes :D Cheers...... Bryan

Bryan -

My precision engineering guy has finally scheduled me some time next week to make a batch of carb parts, so I will soon have a restock (25 of each) of both NC30 and NC35 HRC carb kits, but of interest here is I that also have him making some replacement needles designed to address the midrange flat spot issue - if you can hang on a couple of weeks I`ll be happy to supply you a set...

Rick

r.oliver(at)mtxnet.co.uk

nice one rick,i have some needles your can borrow to look at if you wish