Starter motor??

[greenmonster]

Nice to be in a good MonsterForum again, thx to founders!

Bought one fr a 2000+ engine , don`t remember year or model, f my 900 -97.
It spins backwards. Engaging a gear, sprag engages correctly, chain spins backwards! Is this normal?
Sprag is correctly mounted, not much more could be reassembled wrong. Old starter works OK,  chain in gear spins forward., sprag is engaged.

Have I mounted something wrong? Or some other mistake?
Anyone w same experience?
Or shuld i just stop taking those pills ,
a bit confused here.

[He Man]

Was it a rebuilt motor?

how the hell do you get it to spin the chain? is this an older bike that will start in gear?

The armature could of been wound up backwards. There are also some people who have said if you iinstalled the case backwards it will spin backwards, but i dont belive thats possible since the case only fits 1 way. ( there are 4 magnets inside the case)

[Rameses]

If the old starter works okay, why do you need a new one?


edit: After thinking about the actual question, if your brushes are in the wrong holders, that would make the starter spin backwards, right?

[greenmonster]

Dunno if starter was rebuilt.

Just put in gear, press starter button - chain spinning. Was just checking a few secs as I got more & more puzzled...

if your brushes are in the wrong holders, that would make the starter spin backwards, right?

Maybe, but they only fit one way.

why do you need a new one?

Old has 130 000 km´s on it and is quite worn.

[Howie]

The polarity is reversed, I don't know how somone could accomplish this, so no ideas how to repair it.  If the bike is on a rear stand and the bike is in gear or there is clutch drag the chain will spin with the starter

[Norm]

I have a starter that was rebuilt & does the exact same thing. People whom I've spoken to who rebuild these things tell me that with these particular starters, it's imposible to spin it backwarbs, but.......................................
If you figure out how to reverse the polarity, let us (me) know.

[He Man]

It reallly is impossible to get it to spin backwards unless someone took it apart, and rewound the wires inside backwards. The 4 magnets on the case only fit 1 way, and the brushes are interchangeable. You can only put 1 wire on it. I would get it to a starter rebuild shop, or any electrical shop and ask them if they some wound the armature backwards.

The only other thing ive heard, again, is the shell for it. I've heard that if you put it on the wrong way (its 4 very large magnets on the wall, each one with an alternating polarity) it will spin the wrong the way. But I dont think its possible since it only fits  1 way. (atleast the one i was messing with did)

[Speeddog]

 

If the starter motor is turning backwards, the sprag shouldn't engage, right?

[Howie]

If the starter motor is turning backwards, the sprag shouldn't engage, right?

Ummmm...good point since it is a one way clutch.  Now things make even less sense.

[He Man]

The devil baby from NMC is in on this. Are you sure your not just going nuts? take the starter, connect the power to it, and ground it, does it spin clock wise or counter clockwise?

[bigiain]

The only other thing ive heard, again, is the shell for it. I've heard that if you put it on the wrong way (its 4 very large magnets on the wall, each one with an alternating polarity) it will spin the wrong the way. But I dont think its possible since it only fits  1 way. (atleast the one i was messing with did)

I'm 99% certain that this is possible. If you rotate the shell with the magnets 90deg relative to the brushes it _will_ spin backwards, and I'm pretty sure it is possible to reassemble it and fit it this way. I had an extended chat about it in a thread over on TOB where someone else had done just this, and I recall when re-assembling mine that I noticed it was possible to assemble it both ways and I tested it to make sure I had it spinning the right way (but they're vague 6 year old memories now, and I haven't taken one apart since the question came up).

big

[Rameses]

That still begs the previously raised question though, how does the reverse spinning starter engage the sprag and turn the engine and chain backwards.   


(Unless the starter's turning correctly and the transmission's making the chain spin backwards b/c it's in reverse.     )

[greenmonster]

If the starter motor is turning backwards, the sprag shouldn't engage, right?

That seems logic. BUT,
also have dismounted sprag and flipped sprag a few times during my starting efforts.
Sprag in one direction - didn`t engage engine to turn, sprag flipped 180 degrees - engine turns and rear wheel turns
backwards when checked in gear a few secs.

If you rotate the shell with the magnets 90deg relative to the brushes it _will_ spin backwards,

Interesting! Unfortunately it is apart now so I cannot check how it was put together.
But I did take it apart when bought it to check starter so could be my mistake.
Usually I line up the two fine lines on the shell w the ones on the bottom piece, then the lid w brushes
only fits in one position to get the positive screw from battery in the right position.
Both ends of shell matched, ought to be correct, right?

What happends if you rotate shell 180 degrees wrong?
Split engine last year, sorry no reverse gear... 

[bigiain]

What happends if you rotate shell 180 degrees wrong?

If my understanding is correct, it'll then turn the correct way again - the 4 magnets inside are oriented N S N S, so each 90 degree turn (relative to the brushes) changes the direction of rotation.

big

[greenmonster]

OK, ian.
If you´re correct, at the moment your 90 degree theory seems like the logical explanation.
Maybe I didn`t put it together like I usually do....
Gonna try to test this today.