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Thread: '93 K75 RT-P Starter Issues

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    '93 K75 RT-P Starter Issues

    Quote
    A bad sprag clutch would let the starter spin without turning the engine.
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    I have a 93 K75RTP that seems to have failed, in that the sprag clutch has NOT released.

    I hear a loud whine ( not the normal k75 whine ) when the engine is running coming from the best I can tell near the starter motor. This whine seem to start abruptly during a short ride.

    Has anyone else encountered this and what was the solution?

    Thanks,
    Wes Hoar
    1993 K75RT-P 33K miles
    Last edited by wchoar; 11-07-2013 at 03:19 PM. Reason: lost quotes

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    Wes,

    Welcome to the Forum!!!

    i moved your post to its own thread where i believe it will get more exposure.

    I have personally not heard of this issue. Hopefully, someone will chime in with your answer.


    LONG MAY YOUR BRICK FLY!

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    Lee Fulton Forum Moderator
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    Benchwrenching PGlaves's Avatar
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    If indeed the sprag clutch has stuck engaged (very unlikely) you will know it very soon, I think. Spinning the starter as fast as it will spin with the engine at highway speed will almost immediately destroy the starter motor.
    Paul Glaves - "Big Bend", Texas U.S.A
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    Quote Originally Posted by PGlaves View Post
    If indeed the sprag clutch has stuck engaged (very unlikely) you will know it very soon, I think. Spinning the starter as fast as it will spin with the engine at highway speed will almost immediately destroy the starter motor.
    Up front, I know nothing of this particular mechanical issue, but I think you are correct. If that engine were spinning 5,000 RPM's, let's say, that starter motor would be spinning about 30,000 or more.

    I am wondering if the starter motor gear is not returning back completely, and its teeth are touching the teeth on the flywheel just a bit? Just enough to make a "buzzing" (whining) sound, but not enough to actually spin the gear/starter motor?

    Just a thought from an ignorant person!

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    Quote Originally Posted by jimmylee View Post

    I am wondering if the starter motor gear is not returning back completely, and its teeth are touching the teeth on the flywheel just a bit?
    The K bike starters do not engage and disengage like an automotive starter. They are constantly engaged to the sprag clutch, which is a one way drive. The common failure of the sprag clutch is that it becomes gunked up with varnish and will not lock up in the direction it is supposed to (turning the engine over). The clutch allows the engine to spin faster than the starter, but not the other way around.


    Wes,

    Do you notice a short small metallic clatter coming from the starter area, just as you shut the bike off? If you do, that is the rollers on the sprag clutch falling into position. That is normal and would indicate that the starter and clutch are not the source of the problem.



    LONG MAY YOUR BRICK FLY!

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    Lee Fulton Forum Moderator
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    Quote Originally Posted by 98lee View Post
    Wes,

    Do you notice a short small metallic clatter coming from the starter area, just as you shut the bike off? If you do, that is the rollers on the sprag clutch falling into position. That is normal and would indicate that the starter and clutch are not the source of the problem.
    So that's what that noise is! I was always wondering if it was another shoe about to drop.

    As to the OP ... I note that he has a 20-year-old bike with 33,000 miles on it. The possibility of something gumming up in there sounds very plausible.
    2000 R1100RT / 1987 K75C (RIP) / Santa Clarita, CA

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    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by JamesInCA View Post
    So that's what that noise is! I was always wondering if it was another shoe about to drop.

    As to the OP ... I note that he has a 20-year-old bike with 33,000 miles on it. The possibility of something gumming up in there sounds very plausible.
    When the little pawls (toggles) get gummed up they fail to grip. Given the design I don't see how physics would permit them to grip and not release. If it happened I would expect it to be only momentary and not continuous.

    As for the original noise heard by the OP - there are at least two, maybe three bearings inside the auxiliary case that could be making noise.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
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    A bozo on the bus deilenberger's Avatar
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    +1 on Paul's suggestions. My suggestion, trundle on down to Harbor Freight and buy their "Mechanics Stethoscope" Full price it's $3.99 last I looked. It often is on sale, or has a coupon (see their website) making it $1.99.

    Even at $3.99 it's a tool worth WAY more than they charge for it. Then use it to narrow down where the noise is coming from and get back to us. If I had to make a WAG - I'd be looking at alternator even if the sound seems to be on the port side of the engine. Check the alternator with the stethoscope.. they have been known to have bearings fail (and the vanes in the drive hubs fail if the monkey-nuts deteriorate too much.) If it does have a bad bearing, and you can find an auto-electric place that rebuilds things (rare - but some still DO exist) - it's a common bearing used on Bosch alternators on all sorts of cars. Last time I had one replaced it cost me $10.
    Don Eilenberger http://www.eilenberger.net
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    Quote Originally Posted by 98lee View Post
    Wes,

    Welcome to the Forum!!!

    i moved your post to its own thread where i believe it will get more exposure.

    I have personally not heard of this issue. Hopefully, someone will chime in with your answer.


    Lee, Thanks for putting me into my place. :-)

    I want to thank everyone who has provided suggestions/information!

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    Quote Originally Posted by PGlaves View Post
    If indeed the sprag clutch has stuck engaged (very unlikely) you will know it very soon, I think. Spinning the starter as fast as it will spin with the engine at highway speed will almost immediately destroy the starter motor.
    Paul, I thought that might be the case, but since I don't have much real experience with k-bikes, I thought there was the possiblity the sprag would get stuck.

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    Quote Originally Posted by 98lee View Post
    The K bike starters do not engage and disengage like an automotive starter. They are constantly engaged to the sprag clutch, which is a one way drive. The common failure of the sprag clutch is that it becomes gunked up with varnish and will not lock up in the direction it is supposed to (turning the engine over). The clutch allows the engine to spin faster than the starter, but not the other way around.


    Wes,

    Do you notice a short small metallic clatter coming from the starter area, just as you shut the bike off? If you do, that is the rollers on the sprag clutch falling into position. That is normal and would indicate that the starter and clutch are not the source of the problem.




    Lee, I don't hear the rollers dropping, but my hearing isn't what it used to be.

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    Quote Originally Posted by JamesInCA View Post
    So that's what that noise is! I was always wondering if it was another shoe about to drop.

    As to the OP ... I note that he has a 20-year-old bike with 33,000 miles on it. The possibility of something gumming up in there sounds very plausible.
    James,

    The engine was very clean inside.

    Here's the rest of the story. About 10 years ago I I bought the bike with 11K miles, rode it without problems for two years and 20K miles. Then the whine started. I took the bike apart to find the noise.

    Being a simple minded amateur airhead mechanic, I got frustrated with the process.

    The machine sat in part in my garage for eight years.

    A couple of months ago I had to decide whether to sell the parts or put the machine back together again. So, after a few weeks, it was back together and running. No noise for about 3K miles. Then this last weekend, it started again.

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    Quote Originally Posted by PGlaves View Post
    When the little pawls (toggles) get gummed up they fail to grip. Given the design I don't see how physics would permit them to grip and not release. If it happened I would expect it to be only momentary and not continuous.

    As for the original noise heard by the OP - there are at least two, maybe three bearings inside the auxiliary case that could be making noise.
    Paul, I trust your experience on this. I will get the stethoscope Don recommended and see if I can get a better idea where the noise originates.

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    Quote Originally Posted by deilenberger View Post
    +1 on Paul's suggestions. My suggestion, trundle on down to Harbor Freight and buy their "Mechanics Stethoscope" Full price it's $3.99 last I looked. It often is on sale, or has a coupon (see their website) making it $1.99.

    Even at $3.99 it's a tool worth WAY more than they charge for it. Then use it to narrow down where the noise is coming from and get back to us. If I had to make a WAG - I'd be looking at alternator even if the sound seems to be on the port side of the engine. Check the alternator with the stethoscope.. they have been known to have bearings fail (and the vanes in the drive hubs fail if the monkey-nuts deteriorate too much.) If it does have a bad bearing, and you can find an auto-electric place that rebuilds things (rare - but some still DO exist) - it's a common bearing used on Bosch alternators on all sorts of cars. Last time I had one replaced it cost me $10.
    I will be trundling down to my local Harbor Freight this morning purchase the "Mechanics Stethoscope" .

    After checking with the stethoscope would there be a problem removing the alternator and running the engine to see if the noise goes away?

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    Quote Originally Posted by wchoar View Post

    After checking with the stethoscope would there be a problem removing the alternator and running the engine to see if the noise goes away?
    Just make sure you insulate the ends of the alternator wires so they don't short out.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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