Clutch loud screech whine when clutch is engaged.

Discussion in 'Transmission / Drivetrain' started by impression, Mar 13, 2009.

  1. impression

    impression Member

    Hey all, well i got a new 66cc engine, same one as before. It has nowhere near the power that the last one had and makes a loud screech kinda sound when the clutch is engaged and the bike moves forward :S i have no idea what it is :S any ideas ?

    i've put gease near the clutch bearing and short pin, also the gears on the clutch cover side aswell.

  2. spunout

    spunout Member

    is the new motor broken-in? do you know if your old motor had wrist-pin roller bearings, or was bushing? if it was a bushing, they produced more power. nobody uses them anymore.

    did the whine and screech happen before you applied grease?

    sounds like you need to tighten the clutch pressure plate. look here:
  3. impression

    impression Member

    the new Engine and the old engine are the same batch and same model.

    So i assume they are both either bushing or both wrist.

    old engine is about 3 weeks old, new engine about 3 days.
  4. spunout

    spunout Member

    3 days? ok, well then you wont achieve full power until youre into your third tank, or so.
    but it still sounds like you need to tighten the pressure plate down, if it rolls forward.
  5. impression

    impression Member

    clutch works fine as normal, but whines when engaged, i tightened it as much as i could but still no go.

    I richened up the fuel/air mix by 1 notch in the needle and looking a bit better in the power scheme of things, but still down't like to wind up to full rpm. still only does 30km/h and sounds like its going to blow up at that speed. (44t sprocket)
  6. impression

    impression Member

    ok, i rode the bike to class ( where i am posting from) and max speed down hill was 40km/h but i stopped and checked all the engine after i got to the bottom as it sounded light a jet fighter or something was going to take off from the whining noise :S

    with the clutch, i took the cover off and put a little more grease on the gears.

    I also engaged and disengaged the clutch a few times with the clutch lever. This only pulls one side of the clutch plate. away from the engine,
  7. spunout

    spunout Member

    the "whine" you hear, is normal. its called "mesh gear harmonics". it happens when the gears arent cut perfectly...which these are not.
    i thought you had a constant "screeching" sound. if it just makes the screech when you let the clutch out then the sound stops, thats normal too. thats just the pads grabbing the back of the pressure plate.
    dont expect much for top revs or speed until the motor's completely broken-in.