This topic contains 2 replies, has 3 voices, and was last updated by  Adrian Newnham 7 months ago.

  • Author
  • #1991

    ♠️ MARCEL
    • Topics: 32
    • Replies: 181
    Nov 18, 2018
    North UK
    Points: 2,431

    A stock filter has a cone inside and the material is different = restricted.
    Also it’s a bit smaller than K&N –

    K&N can push 3x more air  = cotton filter in oil coating – so cleaner bike & more free revving yes.  “650 specific”   K&N is good   otherwise  , BMC Italy does it too  (known for race filters on aprillias) – I owned some BMCs in some of my bikes , some K&Ns – they do the justice

    However – an upjet is mandatory  (hence carb tutorial on the forum goes in better detail on jet swapping – just search “carb” at the top of site.

    Running 3x more air on the same stock jets = engine is much hotter , misfires , new piston rings soon lol.

    Likewise, if you have a performance exhaust pipe  –> more gases going out –> upjet is mandatory

    Any air upgrades basically (intake or exhaust) = upjet

    // Meditation doesn't mean you have to sit still....

  • #2299

    Adrian Newnham
    • Topics: 0
    • Replies: 1
    Nov 18, 2018
    Blandford, Dorset
    GT 650 Comet
    Points: 9

    K&N filters are cleanable and have a 1 million mile warranty. The 650 one was £54 and the standard one was £34 which needs replacing every service. It’s well worth buying a K&N as you won’t need to buy another one ever. The fact it adds a little power and helps with fuelling is a bonus.


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