DemonX Pitbike


My pitbike when put into gear will not go, it just revs. I have drained the bike but the problem persists, any feedback would be much appreciated, thank you. {Michelle, Lincolnshire, UK 2009 DemonX DYX140 pit bike}


At the time of writing this page (August, 2012) a 2009 Demon X DYX140 should still be under warranty, so if our suggestions do not fix your problem, or sound like something you are not interested in tackling yourself, you may be able to get help at a local dealer. The DemonX Racing website does not list locations of its dealers but does have a telephone number and email address.

I have located a few sites with DemonX information. No online manuals or fiche though. They do not appear to be available is the US. Some sites list the 140cc model as a DYX140, some as a DX140. All refer to the engine as the YX140, a 4 stroke, 1 cylinder, 2 valve, air cooled engine. Additional specifications are listed below.

Now, on to your answer. The first thing you need to do is check the clutch cable for free play. If the cable is too tight, the clutch is actually disengaged, preventing your bike from going into gear. There is either an easy adjuster located on the cable at the handlebar or two nuts on the cable casing near the right side engine cover. Try turning these adjusters to give the cable additional slack or free play.

Your second task is to try to roll the bike without holding in the clutch lever. If it is in first gear, it should not roll freely. If it rolls freely and your clutch cable has free play, then the clutch springs may have failed or the clutch hub nut has come loose. If it will not roll and the clutch cable is ok, the inner clutch parts {plates, springs} are good.

It is possible that your machine has a clutch adjustment under a plastic cover on the right side engine cover. If you do not see a plastic cover, the adjustment may be internal. In that case a visit to your local dealer is in order.

If your bike is still under warranty, removing the engine side cover yourself or having a mechanic do it for you may void your warranty. Your owner’s manual or paperwork you received when you purchased the bike should have some information about warranty service.

Bike Specifications:

  • YX Motor Sport 140cc
  • 14/12 SDG wheels
  • KMC chain
  • Pro grips
  • Washable Foam air filter
  • Super Grip seat
  • Molkt 26mm
  • Engine type: 140cc XY Motor, 2-valve, 1-cylinder, air-cooled, 4-stroke
  • Bore x stroke: 54 x 54mm
  • Piston swept volume: 128ml
  • Compressing ratio: 10.1:1
  • Max torque: 9.2N.m / 8,500 - 9,000rpm
  • Max power and speed: 8.8kW / 9,000±620rpm
  • Idle speed: 1,500 ±150rpm
  • Clutch type: manual
  • Starting method: kick
  • CDI Ignition
  • Transmission: 4-speed manual clutch (1-N-2-3-4)
  • Min. fuel consumption: 359g/kW/h
  • Chromed 32mm exhaust with alloy end can (muffler)
  • Fully braided brake hoses with 2 pot hydraulic brake calipers
  • Chromolly double tubed cradle frame with powder coated finish
  • Alloy swing {arm} annodised in Demon Graphite colour
  • Demon X rear shock with 1000lbs spring rating
  • Reinforced poly resin fuel tank with CNC alloy fuel cap
  • USD front forks annodised gold with chromed stanchions
  • Forged alloy yokes annodised in Demon Graphite colour
  • Stainless steel foot pegs
  • 2mm steel engine guard, powder coated black
  • High impact polymer plastics with DemonX 3m quality graphics
  • 5mm steel tubular handlebars with matt black powder coated finish
  • 20mm foam bar pad and DemonX cover
  • 14/12 inch SDG wheels with matt black, powder coated finish on hubs and rims

  • Find new and used DemonX parts, accessories and bikes on eBay UK.

    Become a fan of Weeks Motorcycle on Facebook. Get the latest site updates, be eligible for contests, participate in polls and more!

    Need more free ATV or motorcycle repair information?

    Q&A:  Leaking Fuel Valve?
    Q&A:  Leaking Gas Valve flooding engine?
    Q&A:  Battery Maintenance
    Q&A:  Battery Types
    Q&A:  Carb Jetting page 1
    Q&A:  Carb Jetting page 2
    Q&A:  Aftermarket Exhaust System
    Q&A:  Carb Float Needle
    Q&A:  Carburetor Identification

    Q&A:  Honda Points
    Q&A:  Rim Bolt Pattern
    Q&A:  CB750F Identification
    Q&A: Broken Speedometer Cable End
    Q&A: Suzuki LT-Z400 QuadSport Tank Removal
    Q&A: Motorcycle Trike Conversion
    Q&A: Honda Rancher Reverse Problem
    Q&A: Kawasaki Z650SR Fuel Mix problem
    Q&A: RM80 Piston Position

    Q&A: LT80 Engine Oil Issues
    Q&A: Clutch Cable Break In period?
    Q&A: Cooling Fan Problem?
    Q&A: 1983 XV920 Virago Oil Change
    Q&A: ATC90 Spark Plug question
    Q&A: Nighthawk 750 Spark Plug Gap
    Q&A: Bike Registration Problem
    Q&A: Lost Hypercharger Instructions
    Q&A: Bourget Charging System

    Q&A: Can Spark Plugs be cleaned?
    Q&A: Wheel Bearing Removal for 1976 CB750K
    Q&A: 1982 YZ490 Kick Start
    Q&A: 1979 GL1000 Goldwing Points Gap
    Q&A: 1982 GS650GLZ Cable Routing Problem
    Q&A:  Ether vs. Carb Clean
    Q&A:  ATV Ignition Trouble
    Q&A:  John Deere backfiring
    Q&A:  Honda Phantom 200 Tire Pressure

    Q&A:  TRX350 Clutch Slip possible causes
    Q&A:  LTF250 Cam Chain Installation & Timing Marks
    Q&A:  DemonX pit bike clutch trouble

    Weeks Motorcycle Home

    Website upgrade in progress

    Ask a Repair Question

    Search Our Site
    Custom Search


    Vote for our site on Webbie World!

    Weeks Cycle Salvage
    eBay Store

    Show Off Your Machine!

    Show Off Your Machine

    Weeks Gear
    coming soon!

    Sale Banner at Adventure

    Discount OEM Parts

    Classified Listings

    Review on

    Site Build It Affiliate Program