Clutch Clutch types pros and cons

Discussion in 'Transmission / Drivetrain' started by SdCruizer, Feb 2, 2012.

  1. SdCruizer

    SdCruizer Member

    So I see there is a centrifugal clutch
    I guess thats why there are pull starters for sale too

    So whats the pros and cons of this
    I would like to be able to take off from a dead stop with a centrifugal clutch
    not sure how I would like the pull start hanging off the side, but I do like you could start it easier that way

    Also without taking out the clutch is there a way to tell if mine uses the square or round clutch pads, I just got the engine brand new the other day and im told its a 66cc but the epa sticker says 69cc

  2. motorpsycho

    motorpsycho Active Member

    well, I personally have no experience with the centrifugal clutches for the china engines.
    BUT, technically you can take off from a dead stop with a cent. clutch.
    they just slip so the engine can idle, and then when torque is applied the clutch "tighens up" and eventually locks in with no slipping.
    the pull starters for these engines are pretty much junk, and almost every one I've heard about or have seen in person has broken after a very short period of time.
    My frined ordered his engine with a pull starter and it lasted for about 3 days until it broke internally. he ordered a new one, and it lasted about 2 days before it too broke. the rope didn't break, the peice that holds the big coil spring broke, so the spring came unwound in both of his pull starters.
    They are very cheaply made and will not last very long unless someone has come out with with a better one recently.

    the only real way of telling if your engine has round or square clutch pads is to take the clutch apart and look.
    Last edited: Feb 2, 2012
  3. SdCruizer

    SdCruizer Member

    actually I bet with the cen clutch you still have to pedal
    I have a cheap stand up scooter and you have to push off fast then give it gas

    im just used to motorcycles and taking off with the clutch
    so its weird not to be able to do that

    are the clutch pads rubber, they look like it from the pics

    whats the average life on them?
  4. motorpsycho

    motorpsycho Active Member

    hmm, I had a cheap stand up scooter with a 49 c.c. 2 stroke and cent. clutch. I didn;t have to push off to get it to go.
    Just open the throttle & it woudl take off from an idle with no problem.

    I personally don't pedal any of my motorized bikes (they have standard clutches), I ride them like they are motorcycles.
    you shoudl be able top take off with the clutch like on a motorcycle.
    but the centrifugal clutch worls a little different.
    But you should still be able to take off without any push off or pedaling assistance.

    how long do the clutch pads last?
    hmmm, I have no idea but they are cheap to replace.
    yes, the clutch pads are made of rubber, but they are made out of a similar material as radial car tires and there's re-inforcing fibers in them.
    Last edited: Feb 3, 2012
  5. SdCruizer

    SdCruizer Member

    They guy who sold me the engine said not to start from a dead stop

    I had an evo2x 2 speed stand up scooter with pipe and had to push off too, maybe im too heavy

    yeah the beach cruiser im using sucks to pedal so it makes it even harder to get going from a stop
  6. motorpsycho

    motorpsycho Active Member

    well, I have 2 motorized bikes with china 2 strokes on them and i take off from a dead stop without peddling every time i ride.
    I've been doing this for going on 4 years now, with no problems.
    but, My bikes are 20" frames with 20" wheels so mine have a little more low end torque than the 26" bikes with 26" wheels.
    smaller wheels means more low end torque (both have 41 tooth sprockets).

    if peddling your cruiser is hard, there's a simple, cheap remedy for that.
    If your front pedal sprocket is a 44 tooth, count the teeth on your rear pedal chain sprocket.
    if the rear one has 16 teeth, buy yourself a 19 tooth rear pedal sprocket. This will lower your gear ratio and make the bike MUCH easier to pedal.
    OR, you can go to a smaller front pedal sprocket, which will do the same thing.
    Both are simple to change and about the same price.
    changing the gear ratio on the pedal side is one of the first things i do to every bike I buy (unless it's a multi-speed bike).
  7. SdCruizer

    SdCruizer Member

    okay I will count them
    since I know nothing about bikes, is it easy to find the rear since thats easier to change?
    are they all sort of universal?
    I would like to make taking off peddling easier

    Also for the gas engine, I live in massive hill area
    I could use a hair more acceleration
    would I look for a smaller rear sprocket?
  8. motorpsycho

    motorpsycho Active Member

    well, you can find rear sprockets on e-bay pretty cheap. Yes, all coaster brake hub sprockets are the same and they are held to the hub with a snap ring. If you are unfamiliar with taking a bicycle hub apart, you best bet is to take it to a bike shop and let them do it.
    Chaning a rear sprocket is about a 15 minute job start to finish.
    going to a smaller front sprocket woudl give you the same results (like going from a 44 tooth to a 36 tooth) but changing the frint sprocket is a little more work.
    Another thing to consider is that you may have to lengthen or shorten your chain depending on how much chain is on the bike, and which sprocket you change.
    any time you want easier peddling (lower gear ratio) go to a bigger rear sprocket or a smaller front sprocket.

    for the engine rear sprocket, if you want more torque for hill climbing, you woudl go with a bigger sprocket.
    a bigger rear sprocket in this case, lowers the gear ratio and a smaller one will rais the gear ratio.
    for the engine gearing (because the engine sprocket is a 10 tooth), a bigger rear sprocket will give you more torque on take off, faster acceleration, and better hill climbing ability. but there's a trade off, your engine will rev slightly higher at cruising speeds, and your top speed will go down.
    If you want more top speed and less take off torque, you would have to go with a smaller sprocket.
    a smaller sprocket raises the gear ratio, and give you more top end speed.
    this is not good for climbing hills because you lose low end torque and acceleration.
    the cruising rpm's will be lower with a smaller rear sprocket and the fuel mileage will go up slightly. but your top end speed will increase quite a bit.


    You do understand that you don't need a pull start with a centrifugal clutch, right? It has a one way sprag/bearing. you start the engine just like a normal HT. then it's just gas and go from there.
    I have not installed one yet that went right on. Most need a two or three MM spacer for the cover to fit right.
    It's no big deal to remove the five screws holding the cover on or to remove the pressure plate to see which pads you have.
  10. SdCruizer

    SdCruizer Member

    dont the pull starts starter stick out too far and possibly cause the pedal to hit depending on the height of the engine install
  11. motorpsycho

    motorpsycho Active Member

    yes, a pull starter will stick out too far and the left side crank will hit it.
    this requires either an off set crank set, bending the left side crank to clear it, or no peddling.
  12. SdCruizer

    SdCruizer Member

    I was thinking a cen clutch and pull start would be perfect for my dad if I could do it on a trike
    because he can ride an electric bike just fine but cant pedal without loosing balance
    I figured the gas would be faster so maybe a trike is safer
    and he could just take off with the cen clutch and have time to pedal if he could without worrying about falling over
    and pull start it
  13. SdCruizer

    SdCruizer Member

    still havent counted my teeth but came across this
    its easier for me to change this out then the rear (the engine sprockets not the pedal sprockets)
    11T 8MM T8F 05T STEEL

    third bank over 9 down
    Wondering if that engine sprocket fits my ht engine
    is this another option to get the engine to accelerate easier for hills
    or are you supposed to change the rear sprocket