1. Dismiss Notice
  2. Dismiss Notice
  3. Hey Facebook people... We've created a group for XS400.com members to connect. Check it out!
    Dismiss Notice
  4. Want an XS400.com t-shirt? Go to the store to order. Limited sizes and quantities available.
    Dismiss Notice

XS400 top speed??

Discussion in 'The Garage' started by Vloukole, Nov 4, 2013.

  1. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    Hi guys

    What kind of speeds do you guys get at what rpm? My xs will go 120km/h (+-72mph) at +-8500rpm. I read that some people claim that their xs top speed is around 100mph. Are they able to reach such speeds and is mine therefore not tuned correctly? I cant see my xs reaching 100mph.
     
  2. Scorpio1963

    Scorpio1963 XS400 Guru Top Contributor

    If you have sohc engine about 95mph is probably be about it.I don't know how many rpm you`ll be at though.You could probably get more top end by tuning and rejetting the carbs along with a 2 N 1 exhaust system.
     
  3. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    Will I be able to use one of my mufflers and just fab a 2 into 1 header? The exhaust is not stock. Pipe is atleast 1.5".
     
  4. Hishman

    Hishman XS400 Addict

    I have a stock 80. 95mph was what it topped out at i believe it was around 9000rmp. I could have gotten 100 but id rather not push the bike a those rpms for long. Not to mention 100mph on such a small bike is sketchy.
     
  5. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    Mine is at about 8500rpm when doing 75mph. Why the diff? Maybe timing? Carbs?
     
  6. I would say it is a transmission thing. What sprockets do you have?

    Another suspect of course is the speedometer. Most of them are not very exact.

    With 16 / 39 sprockets you should have 100 km/h at 6000 rpm (6. gear, XS400 SOHC).
     
  7. Sesty

    Sesty H.E. Pennypacker

    wind, weight of the bike, weight of the rider, riding position,
     
  8. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    I'll check my sprockets. I believe they are stock.
     
  9. Scorpio1963

    Scorpio1963 XS400 Guru Top Contributor

    Yeah I forgot to mention that yesterday regearing your sprockets will get you more top end speed as well.
    For more top speed you would want to decrease the number of teeth on the rear, or replace the rear with the same and put one with a tooth or 2 more on the front.. vice versa for more torque/acceleration witjh a little less top speed. Its all preference which to do but ive read on this forum that the front is easier to change and swap out if you dont like the result
     
  10. Hishman

    Hishman XS400 Addict

    My speedo is off about 15mph or so. I used my phone's GPS to determine my speed
     
  11. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    Hishman was your speedo above or below actual speed?
     
  12. RevrdMark

    RevrdMark XS400 Addict

    The fastest i can get "cranky" to is about 85mph in full tuck and Wide Open Throttle (and even at that you could time how long it took to get there with a calendar). I have stock sprockets and dual exhaust. I am fat and old so i think going faster on this bike will require my fat butt loosing weight... but that's why i have my SV1000
     
  13. 16VGTIDave

    16VGTIDave XS400 Guru Top Contributor

    RM, weight only effects the rate of acceleration, it has no effect on top speed. I'd suggest looking at your carbs and jetting. You should be able to do better than 85mph. I have no problem doing 85mph with a large windshield and fully upright riding position. And I know that my jetting isn't dialed in perfectly...
     
  14. Scorpio1963

    Scorpio1963 XS400 Guru Top Contributor

    Even stock you shoud be able to hit 90+mph on the sohc bike.Next year Im going to try and push the limits on my bike.:yikes:
     
  15. Hishman

    Hishman XS400 Addict

    OP my tack is slow. Example 30mph on tack is more like 40-45 mph. Pish posh I will be removing it soon anyway.
     
  16. Lou Ranger

    Lou Ranger Former xs400 Luddite Top Contributor

    If your bike is geared to go 72 @ 8,500 rpm it will need to rev @ 11,800 to reach 100 - but if your redline is 10k, your top speed has to stay under 85 mph.
     
  17. FarmBoy72

    FarmBoy72 XS400 Enthusiast

    Fastest My bike has gone is probably 110mph, friend went out after I first got it and opened her up. Needed to blow out the cobwebs. :) He said when he looked down at the speedo it said around 110 and there was still some throttle left. Plenty fast for me!

    78 XS4002E
     
  18. Vloukole

    Vloukole XS400 Enthusiast

    57
    0
    6
    Parys
    But why the huge difference between similar bike?
     
  19. Scorpio1963

    Scorpio1963 XS400 Guru Top Contributor

    110mph what did you do to it?
     
  20. FarmBoy72

    FarmBoy72 XS400 Enthusiast

     

Share This Page