I had my NC35 on a dyno at the weekend. It has an Ethos twin stack exhaust and standard filter. It is running very rich around 5-7K. I have noticed that a popular mod is to put a washer under the needle. This would make the mixture richer still right? I have adjustable needles, so was thinking of dropping the needles one notch to lean it out in this region. What do you guys recommend?

Thanks.

Shimming them is for stock needles, and yes this will richen up the transition phase from needle to main-jet.

What brand of needles you have. Lowering them will lean this phase up.

Hows it feel to ride though? Try leaning it out a little if its superrich but dont get too hung up tuning to a perfect fuel/air graph.

Thanks for the reply. The needles are Kenso I think from what I have found on the web. The bike runs nice up from 9K to the red line, but there is a flat spot around 5K that is a bit annoying.

RVF's run rich from the factory unlike VFR's so its not unheard of to remove the needle washer altogether, some RVF's ive had have run like this. That said you dont have stock needles, are they the ones with the strange jets?

Not looked at the jets, but the needles would point towards the 3 hole Kenso types.

Do the standard needles have a rubber O ring that fits around the needle?

No

I am thinking about pulling them out and going for a standard setup.

The who setup seems a bit odd. The Dyno guy hadn't seen them before and I am now wondering if he put them back with O ring in the right place. I will pull the carbs apart and have a look and maybe drop the circlip one notch to lean things out.

I couldn't get those kenso needles to run right either, spent ages on and off with the carbs and gave up in the end. The standard needles work just fine.

Just butting in on this, my NC35 ticks over lovely and is spot on from 7000rpm up but is really boggy from 4000 to 7000rpm. I have an aftermarket can and a foam filter, is it worth me trying it without the washers on the needles?

Yes but id try a OEM filter first