Hello,

This is my first post, ive just bought a VFR 400 NC30. I love the bike but theres a problem which i think will be the fueling. The bike has a aftermarket exhaust on it. I dont know whether it would of been jetted correctly or not to suit this. The air filter is standard.

What happens is when i accelerate it sufferers a massive loss of power at around 4-6 rpm. After that it seems better but not perfect. It does it in every gear so and the engine ticks over nicely so it shouldnt be a mechanical problem. Feels abit slow but ive owned an r6 for 3 years and have a fireblade so that could be why lol.

I checked the plugs to see if theres anything noticable. The plugs are slightly white. Doesnt that indicate its running lean? Anways hope somone can help me?

Get the carbs off and check the settings, your probably need to raise the needles but your be best off reading through cammo's carbs guide in the V4 workshop section to familise yourself with them

Thank you, ill have a look at the guide. The only carbs ive ever stripped were off a peugoet speedfight scooter so i dont know excaly what im doing with this. Might have to get a garage to look at it.

andy levitt wrote: Might have to get a garage to look at it.

Noooooooooooooooooooo dont do it your end up with a hole in your pocket and a bike no better in most cases

as monkey says mate, cammos guide is real easy, a walk through with pics too, even a monkey could it^ lol no pun intended son

Ive looked at the guide. yeah seems relativly easy. ill have ago at it. anyone recomend a online place where i could buy the main jets from?

andy levitt wrote:Ive looked at the guide. yeah seems relativly easy. ill have ago at it. anyone recomend a online place where i could buy the main jets from?

Wemoto will be the cheapest and compared to an R6 or a fireblade it will seem really slow

Yeah thanks thats what i thought. I was abit unsure what to expect from it. Also im having trouble finding the jets on wemoto. From the guide i try go for 118f and 120r but i cant find them. Is it possible for somone to link me to it please. Thank you.

Jets are jets - any bike shop will have some Keihin jets of that size.

You can also try David Silver Spares online but jets are not special, they are just jets!

allens performance will sort you out..
http://www.allensperformance.co.uk/

call them and tell that what your after as the site isn't as user friendly as it could be. i called on a monday morning and was fitting the jets on tuesday evening.

For the sake of the extra few quid might be worth getting new emulsion tubes (number 35's) too as they can oval off over time and cause odd running and some 0.5mm needle washers to raise the needles.

I fitted 118/120 jets and, drilled the slide holes to 2.5mm and raised the needles 0.5mm then put the bike on a dyno. it is running very slighty rich with these jets (bike is stock apart from a blueflame end can)so i will be downsizing to 116/118.

good luck!