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Discussion Starter · #1 ·
When I first got my 450 the starter worked intermittently.

Tonight I finally bought the stator removal bolt locally ($12, no shipping) and popped the stator off. (I probably could have just bought a long M16 bolt at the bolt store today but didn't think about it.)

Anyway, the stator came off easily enough with the 1/2" drive impact and I promptly had little springs, plungers and round plug all over the place. Luckily I found everything.

I notice that all three of the screws that hold the clutch together were pretty loose and the plate the housing that covers everything was bent as seen in the pictures below.
 

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Discussion Starter · #3 ·
So, I guess my question is, can explain how this clutch works? Are the slots where the round pins sit slotted at an angle so that as the starter motor turns it forces the pins to the outside of the slot and thereby applies pressure to the crank? When the motor starts, and the starter stops, does the springs push the pins back into place away from the spinning crank?

If that's the case, what goes bad with these things? I'm assuming the the bent housing in the pictures above were cause by the screws being loose.

Anyway, I know there have been a lot of questions about starters not working in the past, but I've never seen a explanation on the theory of operation.
 

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Discussion Starter · #4 ·
tbpmusic said:
Yeah, that would do it.
The springs, caps, and rollers are all still available - the plate is not.

I think Ohio Cycle has the plate - http://www.ohiocycle.com/catalog2.html
Are you referring to the flat plate on the bottom or the the bent housing in my picture? I can't even get the housing off either because it's bent, or it doesn't come off.

I took a small hammer and gently tapped the bent housing back into shape.
 

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Discussion Starter · #6 ·
Nice job with the graphics Jayel. That's kinda what I thought but I'm still trying to figure out what can beak.
 

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Actually, the starter motor doesn't initially turn the clutch...it rotates the large gear whose center tranfers rolling motion to the rollers which, by force of rolling direction, move into the narrower area of their cut-outs and "wedge", thereby transferring the rotation to the crankshaft. ...As the engine starts, its greater relative speed "unrolls" the rollers from the "wedge" position at the narrow end of the "cut-out pockets" to the deeper end of the "pockets where they simply "free roll" as the engine runs.... This is one reason that the oil sump has a "hole" to allow oil into the dyno case....The rollers and mechanism must be lubricated, as must the big gear which is now being held motionless against the rotating crankshaft by the starter chain.....
Mike.... ANY signifigant wear on the rollers, gear, or plate and cover can allow the rollers to "cock" and damage the side-thrust plates (causing bulges or cracks)...Loose screws can also allow the entire mechanism or any of its parts to "cock" eventually leading to similar damages.....
I hope this adds to Jayel's explaination which is correct.... :D Steve
 

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Discussion Starter · #8 ·
66Sprint said:
Actually, the starter motor doesn't initially turn the clutch...it rotates the large gear whose center tranfers rolling motion to the rollers which, by force of rolling direction, move into the narrower area of their cut-outs and "wedge", thereby transferring the rotation to the crankshaft. ...As the engine starts, its greater relative speed "unrolls" the rollers from the "wedge" position at the narrow end of the "cut-out pockets" to the deeper end of the "pockets where they simply "free roll" as the engine runs.... This is one reason that the oil sump has a "hole" to allow oil into the dyno case....The rollers and mechanism must be lubricated, as must the big gear which is now being held motionless against the rotating crankshaft by the starter chain.....
Mike.... ANY signifigant wear on the rollers, gear, or plate and cover can allow the rollers to "cock" and damage the side-thrust plates (causing bulges or cracks)...Loose screws can also allow the entire mechanism or any of its parts to "cock" eventually leading to similar damages.....
I hope this adds to Jayel's explaination which is correct.... :D Steve
Excellent explanation Steve. I can picture it now. The bulging is what I'm seeing but, thankfully, no cracks and I guess it was because the screws came loose.

Thanks
 

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I got it right???? :shock: I guess even a blind hog finds a acorn once in a while :lol:
 

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Jayel, ...Of course you were right about the theory.... (you just had the rotational direction arrow backwards)... I just expanded so Mike realized that the screws being loose allowed the rollers to "cock" and "bulge" his/the housing, which acts as a "side-thrust plate and guide" for the rollers....

Mike.... If you hammered the "cover" too tight (beyond perfectly flat with correct clearance), the rollers either may not roll completely into the "wedge" position, or can get "stuck" there and your engine will be turning the starter motor in reverse direction, wasting HP.... (This is extremely rare, only saw it in one case)....If you don't get it "tight" enough, the original problem will re-occur,...... I'd replace the housing and plate (if you can find them) if it shows ANY signs of binding the rollers, or any hesitation releasing...( check by manually rotating/attempting to rotate in both directions after reassembly)....CCW should lock-up in about 10 degrees of turn....CW should immediately release....
 

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Mike-

You'll probably have to look for an intact rotor/clutch on EBay, since nothing you need is still available.
They show up pretty frequently for low bucks.
I have a spare (brand new) plate, but I can't let it go, sorry.......
 

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Discussion Starter · #12 ·
I think the flat plate that I have is fine it's only the bent housing that I'm concerned about.

Now that I understand how the thing works, I'm going to spend a little more time 'massaging' the outer cover then put it back together with the parts I have. It's easy enough to pull apart again if necessary.
 

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Mike .... The "bent housing" IS the OTHER thrust plate that guides the rollers on their "flats"..... a bump or lack of adequate/correct tolerance here (in or out) can cause a repeat of the problem, or the binding I discribed in my previous post.....
 

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Discussion Starter · #14 ·
I put the starter clutch back together this evening installed it along with the chain and starter gear. I forgot to take some pics but we've all seen them a thousand times.

Before installing the chain I rotated the clutch and it locked up instantly and turned freely and smoothly in the opposite direction.

I squirted a little oil in the cylinder and left the plugs out then hooked up a battery to the starter. I turned over nicely for a second or two that I ran it. I tried it about 5 or 6 times without fail so it appears to be working correctly (at least with the plugs removed). We'll see what happens when it's all back together.

Now it's on to the shift drum roller and neutral detent.

Thanks for all the discussion.

Opps, almost forgot to tell another bonehead story. I installed the starter clutch but forgot to tighten the screws tightly so now I have to remove it, tighten the screws, use some locktite and "peen" the screws like the factory (although in this case it doesn't seem to have worked so well).

I thought things were going to smoothly. :)
 

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Better you remembered it now than 50 miles from nowhere when it self-destructs... :oops:

EDIT:...Whew!, That sounded harsh....Sorry!... What I meant was glad you found it out now when the fix is not too bad.....Also glad to hear your gentle hammer tapping managed to save the housing......Good work!.... Steve
 

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So if the starter motor is turning the large gear behind the clutch plate but not engaging the engine this is likely the cause of problems with the roller or springs?
 

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Brushes said:
So if the starter motor is turning the large gear behind the clutch plate but not engaging the engine this is likely the cause of problems with the roller or springs?
Probably.......unless it's the thick housing that they're all in - or the flat plate that the three screws hold on.
 

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In the automotive industry these are known as "one way clutches" or "overrunning clutches" and are most commonly found in automatic transmissions.

The purpose in this application is that if the starter is turning it will cause the engine to turn but if the engine is turning it will not cause the starter to turn.

Consider that the starter turns at its rated rpm to turn the engine at maybe 300 or 400 rpm to get it started. If the engine then turned the starter while the engine was turning 3 or 4 thousand rpm the sarter would explode (which has been known to happen).

Typically the springs get weak or the mechanism gets full of crud and the clutch will not "catch" to make the engine turn so you can't get the bike started. I think it's pretty rare to have them stick the other way.
 

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it looks to be proper... the thing I noticed about the starting system on these bikes is that the design for the positive terminal on the starter motor is really poor. the terminal is at the front of the motor and the brushes are at the back, so they strung a thin metal strip from the front terminal to the brush plate, and I went through two motors where the terminal rotated and sheared the metal strip, leaving it to jam in between the rotor and stator of the motor... that could be your problem as the clutch looks good
 
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