[QUESTION] Gas bikes on trails

Discussion in 'Travelling, Commuting & Safety' started by nashy10, Apr 9, 2013.

  1. nashy10

    nashy10 Member

    Hey everyone im fairly new to this forum, but i have ordered a 80cc (i know its not actually 80) 2 stroke engine kit for a decent mountain bike i have, and my intent is to mainly ride this around dirt trails. I was just wondering how these fair in the mud, and what i could do to possibly make it work better on dirt/mud/loose pack?

  2. crassius

    crassius Well-Known Member

    put some kind of shielding around the air filter intakes
  3. nashy10

    nashy10 Member

    I was considering this
    Last edited: Apr 11, 2013
  4. Anton

    Anton Administrator Staff Member

    I haven't taken mine in the mud before but I think you'd be wanting some decent knobby tires and fenders on the bike. Without fenders you will get mud stuck all through the engine fins and overheat the engine. Motorbike & bike trails are a blast though!
  5. nashy10

    nashy10 Member


    Yeah this would be my main problem, I was thinking of scavenging a dead dirt bike, taking the plastics off it, and modding them to be attached to my bike. But im worried the heat would be too much for the engine or plastics
  6. Anton

    Anton Administrator Staff Member

  7. nashy10

    nashy10 Member

    okay, but since i am going to be going through fairly rough trails, would water splash be an issue with the engine? Would the muffler going under water be an issue? I know with atvs the exhaust can go under as long as you keep throttling it
  8. geebt48cc

    geebt48cc Member


    Make sure engine is broken in first, and chain stretching is under control. The reason I say this
    , is because sounds like you wouldn't be in the best place to have to jump off and repair?!!~
  9. jaguar

    jaguar Well-Known Member

    why not mod the engine to have much better low end grunt for the slow parts of trails as well as for climbing? Just click on my signature link to find out how.
  10. nashy10

    nashy10 Member

    what do you mean by low end grunt? id rather have power and torque than speed if thats what youre referring to.
  11. jaguar

    jaguar Well-Known Member

    Grunt = low RPM torque
    nashy10 likes this.
  12. nashy10

    nashy10 Member

    will look into this, waiting on a bearing for my back wheel to come in until i install the kit. Also, does anyone know of an exhaust that would end like a dirt bikes? Dont like how the stock one goes straight down, manual said i can bend it but im not too sure if i wanna bend it that far. Ive seen people pull this off with extended exhausts but not sure where to buy
  13. V 35

    V 35 Member

    My own experience is you may be very disappointed by lack of torque. Break motor in through a couple tankfuls of gas, torque increases greatly after run in. Check that the clutch releases fully, drive chain is loose enough not to sap power from pedals,chain tensioner is good
    and tight, don't let tensioner hit spokes. You'll probably want to do * a lot * of upgrading, as this sounds like a high stress bike, and chain,
    sprocket, hub [ forget rag joint ] the stock throttle is a joke. A pit bike, or scooter throttle may be used. The exhaust shouldn't be a problem, as the poo poo pipe only hangs down a couple inches below engine case.
  14. Skyliner70cc

    Skyliner70cc Active Member

    I ride mostly forestry service trails in the mountains. I don't do mudding so I can't help you there.
    Couple of suggestions:
    (1) SBP shifter kit install with smaller front drive sprocket and a mega range 1st gear = low end torque and incredible climbing power!!!!
    (2) Tuned Pipe tuned (longer) for low end torque
    (3) Mud/trails = slow speeds with high engine load = little air flowing over cylinder fins= at least 50% castor in your oil to protect engine against from high temps. I've had my exhaust and head glowing read climbing a mountain and castor saved its life. I'm still running the engine today with no repairs. Run 32:1 and you should be fine. When castor oil flashes form high engine temps, it forms a dry lubricant film that provides even better engine protection. You do not wish to get stuck miles away from home. Pedaling sucks. One of my last rides while camping got my engine so hot that it ran with the ignition wire removed from the spark plug. The plug was so hot it was acting as a glow plug. I was very fortunate that castor kept the engine running and allowed me to nurse the engine home after I had a throttle cable break.
    nashy10 likes this.