i have a peugeot speedfight 2.50cc . i want to fit a k/n air filter. what size main jet do i go up? mine has 72 as standard.and needle on top groove in carb (standard setting). anyone help

rayb, June 2009

72 is as good as it gets. the air filter will make little difference on a 50 unless you add a big bore kit. If anything the K+N will be worse in damp or rain; as the standard one is protected from water. I run a standard air filter, size 72 jet, gianelli hand made race pipe with size 6 variator rollers and it clears 50 mph+ you can't get much more without a big bore kit or losing too much bottom end power.

Jeff Cooper ( lord Petersham ), June 2009

hi steo.my speedfight 2. has all been deristricted and a giannelli race exhaust fitted.now want to fit K/N type filter. to give it a bit of excelleration pulling away . any help.

rayb, June 2009

a 72 main jet is big enough for a standard ped with just a k&n filter, you would up-jet if you had fitted a race exhaust. to richen the fuel mix & get a bit more power then raise the needle by inserting the circlip into the middle groove, then turn the pilot air screw in half a turn. bring the ped for a good drive & then take out the spark plug & check for a nice gold brown colour. your set-up is correct if you are getting this, let me know how you get on.

steo, June 2009