Stucked alternator drive.

  • Hi

    Seems that the bearing of starter / alternator shaft has gone ( stucked ) , tried to rotate the "driving dog" ( pos 10…vidual-parts/12_0754.html ) but it refuses to move at all feels like it's welded to the housing. Seems that it's either the "housing dog" or/ and bearing that's gone. Diagnose: it started to sound very laud from the rear of engine and at the same time the charging lamp went on / off / on ,,, by lowering the rew. lamp reminded dark. Tring to crank the engine but the starter would not turn.
    Will remove the drivetrain from the frame in the next days and examine whats happend. [Blocked Image:]

  • Anyone had or heard of the same indication of faults.
    As the "driving dog" are very stucked can I press the axis out from alternator side with removed nut. Or any other trix?

    BTW. have a compleate second engine that I can take spare parts from.
    The mobile workshop with transport engine. Fetched the bike [Blocked Image:] from south sweden a 3200 km roundtrip from home.

    Edited once, last by tibbe ().

  • The drivetrain are in parts and frame hanging above.
    Found the fault, it's on alternator/starter freewheel axis, the innner roller bearing had gone and by this the axis was wobbeling in the end som much that it got stucked to the starter axis. Cleaning som theeth in the starter axis.

    Have to make a new custom made seat for the inner pin roller bearing.
    Or install a repalce engine. Will be this.

    After 20+kkm the bike got to a hault after making a lot of noise and loss of alternator charging.

    Cause of fault: could be that I damage the inner pin róller bearing of the alternator/starter free wheel axis. Was in a bit of hurry putting the engine/bike together.

    Next steep merging the two engines and installing new roller bearing with a new seal for the alternator/starter freewheel axis ( the outer bearing ).

    The original engine has 170kkm while the replacement engine has 40kkm though the cylinder head of the replacement engine has leaking valve sealings so I have to replace them. Guess that the valve sealings can be replaced when the engine are installed. Right?

    Edited 2 times, last by tibbe ().

  • Merging 2 engines to one hopefully working.
    Have to move the timing + oilpressure + engine temp wires and hall pickup from the old engine to the "new".
    A Q. the wire with blue connector unter the tank should it go to oil pressure pickup ur engine temp pickup.

    This is how the alternator axis and starter axis looks [Blocked Image:
    Note that there are teeths missing on the starter gear wheel, but no visible damage on corresponding gears on the alternator axis.
    Second the the splines are nearly compleatly gone on the alternator axis probably because the bearing on the backend was holding the axis failry in place.

    Will put in bearing greese in the inner pin roller bearing, the one that broke, before installing the alternator gear wheel axis, to prevent that pins will fall out or jam.

    BTW. will also swap the bearing in the alternator , seems that both 35A and 50A ( K75 > K1100 + ) has the same bearings 17x47x14 and 12x32x10 Correct?

    Present state of my workshop [Blocked Image:]

  • Got company of a experienced and inovative wrencher yesterday evening.
    Had some great diskussion over technical and human issues.

    Among others we inspected my alternator and it was in a great conndition after 170kkm incl. frequent gravel road riding.
    Got a set of new sealed bearing to install in the alternator but there was no need after our joint inspection.

    Secondly we overlooked the parts I had collected for the back of the engine as starter and alternartor gear axis.
    Checked that all pins where present in the pin roller bearring in the back of the alternator gearaxis. And pre greased that bearing to prelube and hold the pins in place.
    Took out and inserted that axis a couple of time to enshure that no pins where dislocated.
    Prelobricated ( greaseed ) the bussins for starter gearwheel axis.
    Put sealing on tube on tube on the countact to clutch bell house to crancase. And also camchain cover to crancase + cylinderhead.
    A lot of checking and rechecking to enshure a minimal risk for another breakdown. Nock nock.
    Not the funniest thing when it happends and no workshop are close by.
    What's positivly strikes me are the high quality and durability of BMW bikes ( and cars ).
    My old -77 R100RS has limped home ( 2500 km ) several times from central europe to home with f.ex. broken valve lifters and camshaft.
    That bike are "retired" now after 300+kkm touring and are only used for local trips with smile on my lips. [Blocked Image:]

  • This threads contains 3 more posts that have been hidden for guests, please register yourself or log-in to continue reading.

Participate now!

Don’t have an account yet? Register yourself now and be a part of our community!