second alton starter failure - WTF?

ntst8

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Having once had the woodruff key shear i am 100% convinced that installation should be like a head gasket - torque it up, run it, torque it again, repeat until all is tight. Loctite once all is stabilised if you want.
And as for the starter strength - there is something else going on there. When my 850 was rebuilt the kick starter would hold my weight but the Alton spun it over like the plugs were out. I have recently had a couple of no response on the starer button moments, but cleaning the switchgear seems to have sorted that, but I have a spare starter relay on the shelf just in case.
As for Derek W's failure, wow!! I have used those threaded holes to remove the sprag/rotor unit when the woodruff key smeared. I will now be taking a close look for cracks.
 

Derek Wilson

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now that i got the humor aside - informative write-up. please keep me or us informed on any improvements you come up with.
Here is what I am thinking:
Starter Drive Assembly.jpg


1. Thicken the flange in the area where the stress is the highest. I have tripled it, but then tapered it back in so that it mounts the alternator rotor in the same place. I am lengthening the crankshaft nut to compensate for the thickened flange.
2. Carry the torque into the main drive sprocket, by lengthening the hub and engaging it with the spacer that now bolts to the drive sprocket via the puller bolt holes. I am guessing that this is what the so-called "Yves fix" does. I show a hex, but I am thinking of simplifying this. I don't relish the idea of machining an internal blind female hex.
3. Make the whole thing out of better quality steel. I was shocked at how soft the drive flange was when I was trying to get it apart. I am using annealed 4140 - still has a Yp of 90 ksi - about three times stronger than mild steel.

FWIW.
 
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Derek Wilson

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Were you able to get the sprag clutch / rotor assembly off.... If not, how about a kind of make shift slide hammer/ I've done this before when there is no room for a puller on things. Using a wire cable or cables, attached to either side or behind , give yourself enough slack or room to swing a sledge hammer away from the part and into the cable. You can suspend the cable with a piece of 550 cord or similar just to get your fingers out of the way of the hammer.
I pulled mine with a 2 jaw puller, once the alternator stator, mounting plate, and drive chain were out of the way. No drama at all.

Getting the hub off once the drive flange has sheered off is another story.... vise grips, pry bars, liberal use of the F-bomb....
 
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Here is what I am thinking:
View attachment 80292

1. Thicken the flange in the area where the stress is the highest. I have tripled it, but then tapered it back in so that it mounts the alternator rotor in the same place. I am lengthening the crankshaft nut to compensate for the thickened flange.
2. Carry the torque into the main drive sprocket, by lengthening the hub and engaging it with the spacer that now bolts to the drive sprocket via the puller bolt holes. I am guessing that this is what the so-called "Yves fix" does. I show a hex, but I am thinking of simplifying this. I don't relish the idea of machining an internal blind female hex.
3. Make the whole thing out of better quality steel. I was shocked at how soft the drive flange was when I was trying to get it apart. I am using annealed 4140 - still has a Yp of 90 ksi - about three times stronger than mild steel.

FWIW.
SUPER! you are definitely on to something here. i'm by no means a machinist, but a can see where a female hex would be problematic. you might consider a two sided flat, similar to "yeves" - that along with your thickened flange might be a viable solution to the whole problem. by increasing the thickness, it allows you to simplify the spacer design. from what i can see, locking the rotor-clutch mechanism directly to the engine's drive sprocket is the key. to all this. aside form the female hex, your spacer design looks like a winner. BTW, if you are not familiar with the yeves fix, here's a link - https://www.accessnorton.com/Norton...-solution-for-broken-woodruff-key-2017.24163/
 
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MM, we were taught that small voltage drops can cause hell with starter motors. I have been out of the trade for 21 years so figures are a distant memory,. Cumulative voltage drop is kind of ok, but if its all from one place, fix it. We had to guarantee the cars left our workshop with no further troubles, so we had to check where the voltage drop existed, and clean it up.

looking at the pictures of the Alton set up, I am glad I don't have one. Then new one from CNW looks a lot more substantial. Glad my legs are still ok and that my bike usually starts first or second kick.

The issue with the key shearing reminds me of what I have found on my 1923 Dodge engine. The front sprocket and oil pump drive gear are loose on my crank. They are held in place by a retainer that has a pin driven through it and through the crank shaft. No compression of the parts and therefore all the load is on the key. Not a good way to do that but that technology is 98 years old now.

Dereck
 
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I pulled mine with a 2 jaw puller, once the alternator stator, mounting plate, and drive chain were out of the way. No drama at all.

Getting the hub off once the drive flange has sheered off is another story.... vise grips, pry bars, liberal use of the F-bomb....
how do you get the drive chain off (after the stator is removed) while the sprag clutch assembly is attached to the crankshaft? i've got some sort of casting boss, forward most 9 o'clk position, on the inner primary case that keep the chain captive as long as the sprag clutch assembly is in place.

IMG-2722.jpg

if i could get the chain off, my three jaw puller would probably work. right now, looks like in need to fab some sort of plate i can bolt to outer clutch flange that has something to pull against.
 

Derek Wilson

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SUPER! you are definitely on to something here. i'm by no means a machinist, but a can see where a female hex would be problematic. you might consider a two sided flat, similar to "yeves" - that along with your thickened flange might be a viable solution to the whole problem. by increasing the thickness, it allows you to simplify the spacer design. from what i can see, locking the rotor-clutch mechanism directly to the engine's drive sprocket is the key. to all this. aside form the female hex, your spacer design looks like a winner. BTW, if you are not familiar with the yeves fix, here's a link - https://www.accessnorton.com/Norton...-solution-for-broken-woodruff-key-2017.24163/
Yeah, that looks simpler for sure. Rev 2 coming. Cheers!
 

Derek Wilson

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how do you get the drive chain off (after the stator is removed) while the sprag clutch assembly is attached to the crankshaft? i've got some sort of casting boss, forward most 9 o'clk position, on the inner primary case that keep the chain captive as long as the sprag clutch assembly is in place.

IMG-2722.jpg

if i could get the chain off, my three jaw puller would probably work. right now, looks like in need to fab some sort of plate i can bolt to outer clutch flange that has something to pull against.
You don’t have to take the chain off completely, just move it out of the way so you can get the puller jaws onto the sprocket.

Yeah, I know, not elegant, but I did not hurt the sprocket at all.
 
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Hello. I'm interested in this thread. I recently fitted the Alton starter to my 72 Combat, and it has been absolutely faultless.
However, I had problems with that crankshaft nut, because it was very tight on the thread, and could not be screwed on by hand. The original nut was no problem at all. I asked Alton to send another nut, which they did by return of post, and the replacement was a little better, but there was still no way it could be screwed on by hand, and it got tighter as it got further on.
I thought about running a die down the thread, but I was concerned about messing about with crankshaft. Anyway, I went with it as was and it torqued up to 70 ft lbs with no problem,and I used loctite as recommended.
Based on what is being said here, I'm now worried that with a tight thread, maybe not all that torque is being applied to clamping the parts together, so I'm thinking that perhaps I should dismantle it and do something about that thread.
I don't have the facilities, or the skill, to re-engineer the parts.
 
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Based on what is being said here, I'm now worried that with a tight thread, maybe not all that torque is being applied to clamping the parts together
Correct, torque figures are based on the correct thread, maybe a tap run through the nut would be better than running a die on the crank. As the original nut worked then it sounds like the Alton nut is wrong not the crank.
 

Fast Eddie

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Hello. I'm interested in this thread. I recently fitted the Alton starter to my 72 Combat, and it has been absolutely faultless.
However, I had problems with that crankshaft nut, because it was very tight on the thread, and could not be screwed on by hand. The original nut was no problem at all. I asked Alton to send another nut, which they did by return of post, and the replacement was a little better, but there was still no way it could be screwed on by hand, and it got tighter as it got further on.
I thought about running a die down the thread, but I was concerned about messing about with crankshaft. Anyway, I went with it as was and it torqued up to 70 ft lbs with no problem,and I used loctite as recommended.
Based on what is being said here, I'm now worried that with a tight thread, maybe not all that torque is being applied to clamping the parts together, so I'm thinking that perhaps I should dismantle it and do something about that thread.
I don't have the facilities, or the skill, to re-engineer the parts.
I would definitely remove and investigate further as some of that 70ft lbs has definitely been absorbed by that tight thread rather than being applied as clamping force.

I’ve never seen an Alton rotor so I don’t know what is being compressed when tightened, but given the importance of the clamping force actually taking the load of the starter, I would have thought more torque would be in order?
 
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cliffa

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I just looked back through my posting and can see I installed the nut with the lip facing outwards and you can also see the thick serrated Bellville washer I installed underneath it..

1623065518051.png
 
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I would definitely remove and investigate further as some of that 70ft lbs has definitely been absorbed by that tight thread rather than being applied as clamping force.

I’ve never seen an Alton rotor so I don’t know what is being compressed when tightened, but give the importance of the clamping force actually taking the load of the starter, I would have thought more torque would be in order?
I would definitely remove and investigate further as some of that 70ft lbs has definitely been absorbed by that tight thread rather than being applied as clamping force.

I’ve never seen an Alton rotor so I don’t know what is being compressed when tightened, but give the importance of the clamping force actually taking the load of the starter, I would have thought more torque would be in order?
i've said this more than once, in a perfect world, it's a good design. in the real world, i have doubts. in a nutshell, the sprag clutch-rotor retaining nut is supposed to provide sufficient clamping force to keep the starter's clutch assembly from turning on the crankshaft, thus not shearing the woodruff key. that nut squeezes the rotor-clutch and spacer against the engine's drive sprocket. the whole thing depends on the nut's torque and surface contact area of the nut. to me, even at 70 ft.lbs., the contact area may be insufficient for the task. now i'm thinking, the nut which also has a step flange, and that step might be engaging on it's corresponding step on the crank before full torque is achieved. if that is truly the case, it's very possible that the nut to sprag clutch clamping torque is not seeing the full 70 ft.lbs .

i have some belleville spring lock washer's that are serrated on both sides. that washer should kick out the retaining nut enough to eliminate any possible step flange interference. the washer has by design, a double locking force - the spring action and the serrations. i've got myself convinced that, that will solve the problem, however i'm also going with the "yeves" design fix.

IMG-2723.jpg
 
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I remain somewhat confused by the problems since my Alton has been functioning perfectly for almost 8 years now. I wonder if they have changed (cheapened) the design since early '13, when they redesigned the rotor. The most difficult part of the installation for me was adjusting the clearance between the stator/rotor which, due to the fairly close tolerance of the Alton parts, was a bit fiddly. But, again, the starter has been totally bulletproof and I have been extremely pleased with it. I realize that me saying it has been bulletproof is no help to Joe and the problem he is having. I'm just trying to figure out why there would be a problem with one kit and not another. Maybe there are inconsistencies in the parts themselves? But I have been extremely pleased with the Alton and haven't seen any need to modify it or 'strengthen' it in any way from its totally as-delivered configuration.

I agree that the CNW starter appears to be a better design. But when I purchased the Alton in late '12, the CNW starter was not yet available. However, even if it had been, I would have selected the Alton because I don't want to convert to belt drive and I want to retain the original ham can air filter. Also, from a general appearance point of view, the Alton system is less noticeable, which I also prefer.

When I had problems with the original (late '12) Alton rotor, Alton was excellent with support. They sent me a new (original style) rotor from France to Mexico in less than 5 days, paid all shipment, Mexican customs and for shipment of the failed rotor back to them. When the 2nd one failed, they had redesigned the rotor and did the same thing - paid for the shipment/customs of the new rotor AND shipment back to them of the failed rotor. SO...I'm thinking (hoping) that unless their service has degenerated, they will do whatever is necessary to correct the problem Joe is having.
 

BERT

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how do you get the drive chain off (after the stator is removed) while the sprag clutch assembly is attached to the crankshaft? i've got some sort of casting boss, forward most 9 o'clk position, on the inner primary case that keep the chain captive as long as the sprag clutch assembly is in place.

IMG-2722.jpg

if i could get the chain off, my three jaw puller would probably work. right now, looks like in need to fab some sort of plate i can bolt to outer clutch flange that has something to pull against.
I removed mine with the engine sprocket puller. The holes on the Alton rotor are tapped and are spaced the same as the engine sprocket. There are minimal threads and the guts of the rotor are close and easily damaged by the puller bolts. I was very careful and this one came off with the chain as a unit. This was 5 months ago, but all to the best of my recollection. I need to add that there was no damage to this unit, it worked fine, I removed it for repairs to the bottom end.
 
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BERT

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I remain somewhat confused by the problems since my Alton has been functioning perfectly for almost 8 years now. I wonder if they have changed (cheapened) the design since early '13, when they redesigned the rotor. The most difficult part of the installation for me was adjusting the clearance between the stator/rotor which, due to the fairly close tolerance of the Alton parts, was a bit fiddly. But, again, the starter has been totally bulletproof and I have been extremely pleased with it. I realize that me saying it has been bulletproof is no help to Joe and the problem he is having. I'm just trying to figure out why there would be a problem with one kit and not another. Maybe there are inconsistencies in the parts themselves? But I have been extremely pleased with the Alton and haven't seen any need to modify it or 'strengthen' it in any way from its totally as-delivered configuration.

I agree that the CNW starter appears to be a better design. But when I purchased the Alton in late '12, the CNW starter was not yet available. However, even if it had been, I would have selected the Alton because I don't want to convert to belt drive and I want to retain the original ham can air filter. Also, from a general appearance point of view, the Alton system is less noticeable, which I also prefer.

When I had problems with the original (late '12) Alton rotor, Alton was excellent with support. They sent me a new (original style) rotor from France to Mexico in less than 5 days, paid all shipment, Mexican customs and for shipment of the failed rotor back to them. When the 2nd one failed, they had redesigned the rotor and did the same thing - paid for the shipment/customs of the new rotor AND shipment back to them of the failed rotor. SO...I'm thinking (hoping) that unless their service has degenerated, they will do whatever is necessary to correct the problem Joe is having.
I also had excellent service with them. Paul was prompt with emails. I believe they are in it for the long run and try to keep their customers happy.
 

Derek Wilson

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SUPER! you are definitely on to something here. i'm by no means a machinist, but a can see where a female hex would be problematic. you might consider a two sided flat, similar to "yeves" - that along with your thickened flange might be a viable solution to the whole problem. by increasing the thickness, it allows you to simplify the spacer design. from what i can see, locking the rotor-clutch mechanism directly to the engine's drive sprocket is the key. to all this. aside form the female hex, your spacer design looks like a winner. BTW, if you are not familiar with the yeves fix, here's a link - https://www.accessnorton.com/Norton...-solution-for-broken-woodruff-key-2017.24163/
Did a little more work this morning - this looks easier to make:
Starter Drive Assembly, R1.jpg


Two changes:
1. Hex replaced by 2 drive tangs (5/8" wide, ~1/2" of engagement) - easier to produce
2. Countersunk screws holding drive member to main engine sprocket replaced by low head socket head screws - can loosen tolerances,

FWIW
 
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What purpose does the lip serve if it's facing outwards?
not flaming anyone, but one thing i see in cliffa's photo - the retaining nut, with the flange outward and the belleville washer, appears that the nut does not have a full , 100% thread engagement on the crankshaft. i always try use the minimum 1-1/2 thread showing on the male threads on any fastener.

note, on my Mk2, the retaining nut has full thread engagement w/ some crank thread showing. i also have sufficient clearance to add a bellville washer to the assembly. i would imaging, most likely, no two bikes are the same.

IMG-2724.jpg
 
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