Keihin MX FCR 39 on an 03 640 Adv?

Discussion in 'Thumpers' started by overlandr, Mar 9, 2004.

  1. overlandr

    overlandr Dystopist

    Nov 30, 2003

    I am looking at getting hold of this carb from an 03 525EXC - cheap of course! The point is -

    Has anyone else got this carb on the same bike?

    Is fitment and set up going to be a hassle?

    Do I need to get a loads of other parts to make it fit?

    Will it greatly improve the mid end performance and economy ?

    Is it generally suited to the engine - I see this carb is used in the 02 660 Rallye Engine

    Where can I get Kehin parts - preferably in OZ?

    Any information on this match would be good. Cheers People :wave
  2. neduro

    neduro Addict

    Jul 8, 2003
    Colorado Springs, CO
    I've got no direct experience with this conversion, but I know the FCR is a fantastic carb once tuned. The trick is, it's difficult to tune correctly, so I'd be wary if I wasn't ready to mess with it a bunch. Hopefully you're also comfortable with jetting and have have access to an EGR and a Dyno.

    If you can get it dialed, though, I bet you'd really like it.
  3. Tim

    Tim Long timer

    Dec 9, 2002
    Guernsey, Channel Islands, UK
    People seem to run FCR41s on 640s rather than the 39, but I would guess that you should be able to get it set up OK.

    Try asking at KTMtalk, a guy called James Dean (made up name?!) seems to be very knowledgeable.
  4. Flanny

    Flanny Flanny-it-up!

    Feb 18, 2003
    Ottawa, Ontario, Canada, the World, the Universe
    The 39mm should actually be better than the 41 on the 640 for the dirt...more low end response, while still have the "snap" of a pumper...

    The 41 is more intended for supermoto due to the big top end gains...
  5. Mack

    Mack Gone, but never forgotten. RIP, Mack...

    Sep 7, 2002
    Austin, Texas USA Native Oregonian
    Flanny, and group. As I'm getting ready to pull the trigger, and order a Keihin for my 640 ADV, if anyone has additional feedback it would be appreciated. In an ideal world, I'd have dyno charts to look over for a BST 40, TM40, FCR39, and FCR 41 equiped 640 ADV. I'm pretty commited to the FCR 41, as the bike will see just as many street miles as off road miles, and it seems the bottom end is strong enough as is, but more top end when riding with GS's, into headwinds, etc. is always a plus. Then again, the Rallye 660/700's certainly don't seem to be lacking in top end! Thanks, Mack

    PS. It looks as if the kit isn't all that, with many complaining of throttle cables that don't work that well, and poor fitting carb adapters. I might just end up buying the carb, and using the RFS throttle cables, and intake boot. (Overlandr, if your getting all the above with the carb, at a good price, it sounds like it would be a pretty good deal.) I'm off to KTMtalk.