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    old red eyes

    My kz750 B3 only occasionally starts on the button , as I’m getting older it’s not so easy to kick start. I presumed it was starter clutch so took off cover to check it out. It appears to me to be a ” lazy ” starter motor. With the cover off it turns engine well but as soon as cover goes back on it struggles, possibly due to extra resistance of stator/generator. Best road to go down would be ? Btw the battery is showing 12.8 v.


    Try again with a car battery via jump start cables connected.
    If that shows the same result, most likely the coals/sliding contacts in the starter motor are worn. Check the springs as well. Repair kits available, at least in the USA.

    There shouldn’t be a difference when using the starter motor, either with cover fitted or not.
    Is there a paper gasket used or just “fluid” sealing compound ?

    There are two reasons for starter malfunction:
    – One is the starter itself (no power)
    – The other reason is the starter freewheel clutch.

    If the starter has no power, it turns the engine or not, just stops working at some point or works very slowly.

    The freewheel clutch is a very common issue. It does not engage to turn the crankshaft, but the starter turns up to this freewheel clutch. That makes a terrible noise.

    What is it in your case ?

    Cheers, Michael (from Germany)

    old red eyes

    Hi Michael In my case it seems to be starter turning engine too slow, it works better when engine is warm but not always. I tried connecting it to my Africa Twin but still no good , will try with car battery over weekend .


    I have a similar problem with my CSR. The starter seems to really struggle turning the engine over. After saying that she always starts on the button.

    I do agree with Michaels comments. One other possibility to me is a tight engine. When my engine gets very hot it seems tighten up and can stall. I have to kick her then as the button has no effect.

    I intend to strip her down this winter and investigate the issue.

    I will also be overhauling my starter motor and giving her new bushes and brushes etc


    a warm engine is harder to turn than a cold engine.
    Probably the engine heat warms up the starter motor and eases its job ?

    First thing to do is to clean the collector and to fit new brushes/coals[?].
    Also clean the gaps of the collector with a small tool. Soft material (plastic) is prefered over metal objects.

    To disconnect the PLUS-cable, ensure the internal screw/stud doesn’t turn. If it does more than approx 30° the internal copper strips will brake off (last pic) !
    Use a simple, but flat 10mm spanner to hold it, e.g. available from bicycle dealers as universal tools for just 1 pound.

    Never disassamble the 4 screws circular to the housing !

    For reassambling of the starter motor the alternator cover must be off.

    Pay a lot of attention to the washers and their sequence !!!

    You can’t remove the rotor to the Brush/coal side. Just leave it in the housing to clean the collector.

    Cheers, Michael

    PS: I describe this brushes/coal side as the electrical side of the starter motor.
    The other side is the mechanical side. It is more complex and not straight-forward to reinstall.
    Pay even more attention to the washers there ! One sticks always at the rotor, make sure to catch that.

    old red eyes

    I got an electrician that I work with to make me up a new heavier starter motor cable, tried it this morning big difference started on the button. I wonder if it would be worthwhile making up a new battery to solenoid cable.


    If you have any doubt about the condition of this cable, replace it !
    Check correct/needed/improved cable diameter size, as there is no fuse in this powerful electrical circuit.
    In this case: “Bigger is better!” 😉

    Pay attention to have good positioning (90° cable shoe) and insulation of this PLUS-cable against batterie holder and frame.

    Good luck !

    Cheers, Michael


    My B1 struggles if I open the throttle when trying to start, the motor just stops momentarily as it has too much compression, Easy fix, Don’t open the throttle, It has never ever failed to start. Years of big singles and V twins have taught me this. 😉

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