My Bike Is Broken

Discussion in '2-Stroke Engines' started by atomichurley, Nov 23, 2009.

  1. atomichurley

    atomichurley Member

    I was riding my bike today it has a Zbox 2 stroke 66cc engine i came up to a large hill so i pulled my clutch in and rolled down the hill when i got the the bottom of the hill i let the clutch back out i obviously was going to fast my clutch cable snapped and the bike while skidding 20m the rear tire popped.
    I will be replacing the rear tire and the clutch cable. Does anyone have any advice when coming down hills regarding the clutch?

  2. Hawaii_Ed

    Hawaii_Ed Member

    best advice is to not let it freewheel and overspeed. Leave the clutch out and let it reach max engine speed and hold there. My good friend was killed on a motorcycle just like that. Pulled the clutch, freewheeled down a hill, popped it out in too low of a gear at the bottom It slid over, throwing him into oncoming taffiic.
  3. Al.Fisherman

    Al.Fisherman Active Member

    Although I don't know if it is good for the engine or not, while applying brakes, clutch engaged I hold the kill switch in while coming down a hill. I use the engine as a secondary brake.
  4. AussieSteve

    AussieSteve Active Member

    I pull my clutch in for down hills too, but you need to wait until you're back down to a pretty slow pace before letting the clutch back out. A speedo helps, otherwise it's hard to judge sometimes. It pays to give the throttle a blip at the same time, to bring the revs up to match your speed. Like when changing down a gear on a motorcycle.

    (Mine's also a ZBox 66cc.)

    ... Steve
  5. atomichurley

    atomichurley Member

    Thanks for your advice guys. i'm in the process of salvaging the motor of my bike and buying a new frame cause the one i have it just junk does anyone had any idea of what frame i should buy? thanks
  6. Hand Made

    What are you looking for in a ride? Rigid? Suspension(Prob)? Schwinn 88 Rocket? I think?
  7. arceeguy

    arceeguy Active Member

    With the ignition off, and clutch still engaged - the engine will still be drawing fuel but not burning it. The raw fuel/oil mix has about the same lubricity as raw gas, and will wash the lube off of the cylinder walls, bearings, etc.

    When I go down a long hill, I pull the clutch in and let it idle and use the brakes to keep the speed within reason. I know I could just let it coast and hit amazing speeds, but I would hate to have a tire blowout (or a clutch cable snap) going so fast. When I hit the bottom of the hill, I hit the throttle and engage the clutch - matching the RPM's as described above.
  8. ToeCutter66

    ToeCutter66 New Member

    Dont forget the possibility of shock cooling the engine. If it is a steep hill and you get going real fast, and the engine is at idle, or has the kill switch engaged, you just might crack a cylinder.
  9. Whe coasting down a hill, pull in the clutch and let it idle, when you reach the bottom wait til you are doing around 10mph or so and slowy release the clutch while giving it a little throttle to pick up some speed.

    Wasn't that hard just to give the correct answer, i dont know where the other crazy ideas come from.
  10. motorpsycho

    motorpsycho Active Member

    wait...what in the h*ll are you talking about?
  11. motorpsycho

    motorpsycho Active Member

    exactly. A little common sense goes a long way.
  12. GearNut

    GearNut Active Member

    Shock cooling/ cracking a cylinder or cylinder head? On an air cooled engine? What???
    As many times as I have ridden my dirtbikes around in a river; picture going from a few hours of playing in the hills and valleys, then hitting the river without any cool down what-so-ever, I have never, ever experienced or heard of such a thing.
    And If a sudden jolt of icy river water did not crack those engines, how could air blowing past an air cooled engine cause cracks?
    Now if you are talking about overheating a water cooled car or truck engine then pouring water into a hot,overheated radiator, then yes, you can and most likely will crack the engine block.

    Back to the subject:
    I gotta agree, pull in the clutch when going down a hill. When you get to the bottom of the hill, wait untill you slow down to a very reasonable speed, rev up the engine a bit and slowly release the clutch to match the engine speed to the bike's speed.
    If you are going to be coasting for a long time, pull in the clutch, kill the engine and coast. Never, EVER, let the engine act as a brake while going down a loooong hill. The closed carburetor will not let in enough oil mixed fuel to let the engine receive proper lubrication at high engine speeds. High engine speeds that are driven by the back tire force spinning the engine.
    Last edited: Jan 18, 2010
  13. retromike3

    retromike3 Member

    to idle or not

    I try to commute over a pretty steep hill five times a week and what I do is let it idle and pull the clutch in when I am going downhill. I have been known to reengage the engine when I started to slow down, but I always give the throttle a goose before I do so. I try to keep from using the engine as a brake because of the potential damage you can do to the engine by staving it of lubrication. Since I have broken my engine in it has been running pretty good and my spark plug looks good (gray not black or melted).
    I have had a problem in the past when I lost a chain, But I think that was caused by my cog bolts getting loose. It happened when I tried to release the clutch at the bottom of the hill in the middle of a tunnel. Boy was that a mess.
    I think the best thing to do is let it idle, I think that if you are careful you will put less wear on the motor/clutch if you don't have to push start it so often. What do you folks think?

    Mike Frye -the bike guy
  14. GearNut

    GearNut Active Member

    That seems reasonable, Mike.
  15. bigdan

    bigdan Member

    I ride to work almost everyday over a few hills. When I'm going down hill, I pull the clutch and kill the engine and I start the motor back up at the bottom of the hill. It just seems dumb to burn gas when I can coast for free. I'm also only going about 5 - 10 Mph when I start it back up so it's not a big strain on the clutch. I definitely would not try to start the motor at anything faster than about 10 Mph. I've been doing this on the same motor for 2 years now and I haven't had any problems yet.