Piston- Queston

Discussion in '2-Stroke Engines' started by adrian101, Aug 5, 2011.

  1. adrian101

    adrian101 Member

    Does it matter which way the Piston goes in?

    I have a 66cc piston (new) and on the top of the piston it has the number 5 and a arrow.

    Does the arrow point towards the exhaust port or towards the intake port once the cylinder jug goes over the piston?

    Any help is much appreciated

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Yes, it matters what way the piston faces.

    Look carefully at the piston ring grooves to see the 2 round pins
    that locate the ends of the rings.

    Those pins go to the back of the cylinder on each side of the intake
    If you install the piston in the cylinder with the ring ends not against
    the pins you will break the rings.
    Also the rings must be installed the right way up with the angled ends
    around the pins.
    Last edited: Aug 5, 2011
  3. adrian101

    adrian101 Member

    Thank you. :bowdown:
  4. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Did your new piston come with the rings on it?

    I presume that the arrow faces towards the exhaust but most
    of the pistons I have now have no arrow or other markings.

    Hey, you have a hotted up bike. Are you Aussies going to start
    having Motorized Bicycle Races?
    If you need help with the planning let me know if i can contribute
    some of my race organizing experience.
    Last edited: Aug 5, 2011
  5. adrian101

    adrian101 Member

    yeah the piston came with the rings already on. Now that I've placed the piston on the con rod the arrow is facing the direction of the exhaust port.

    Yeah i have my engine with performance parts on it, I don't know if there are races with motorized bikes here in Australia, I've never checked lol
    If there was I'd win ;) lol
  6. HeadSmess

    HeadSmess Well-Known Member

    give over, its australia and we have to get around on pushies! 18months and while ive seeeeeen two other bikes putting round, i havent met anyone else yet :p

    and hate to say it....id win ;)