Alton starter

baz

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thanks baz - got to eat crow on this one. i didn't have any spares after my two woodruff key failures, so i bought a section of poly rod and fab'd my own. problem is, i used 3/8" rod (.375 ) whereas should have known better and used 10mm (.3937) - that's a difference in diameter of .0187" and enough of a difference, that i ate through those slightly smaller pieces after about a dozen starts. lesson learned, problem is, i've got to tear into the alton assembly again. this will be my third time, and hopefully the third time's a charm! based on brutis61's post, i might try adding a forth shear pin.
The 10mm pins are a very tight fit
 

gortnipper

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Why would those pins continue to fail? Seems as though there must be some issue that is causing excessive stress on them.
I don't know, but a metal hemisphere pushing around a poly rod? Something about shear strength?
 
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I have never had such a failure on my Alton, installed in '12. So I was thinking there might be something causing excessive force. Maybe severe kickback due to improper timing/faulty EI? Just speculating...
 

baz

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Yep the pins are effectively a fuse in the system
It shouldn't keep blowing
 

baz

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Of course it could be that using 3/8 instead of 10mm is allowing a certain amount of snatch that is shearing the pins
I took a brand new drive apart yesterday to measure the pins
And they were extremely tight in there
 

Fast Eddie

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Surely it’s also possible that home made pins are not of the exact material specification required ?
 
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"Of course it could be that using 3/8 instead of 10mm is allowing a certain amount of snatch that is shearing the pins"

A failure makes sense to me under that condition. ;)

"Surely it’s also possible that home made pins are not of the exact material specification required ?"

A failure makes sense to me under that condition. :)
 
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Why would those pins continue to fail? Seems as though there must be some issue that is causing excessive stress on them.
good question - i've had more issues with alton and my Mk2 than i care to admit. t've sheared two sprag clutch woodruff keys, and i'm guessing the ploy pin failure was somehow connected to those failures. this last poly pin failure was totally my f-up. i really think there is a compatibility issus between my alton kit and mty 74 commando - what it is, haven't got a clue. i do experience some kickback and backfire, and i did have my original tri-spark failure, and that, i'm thinking, was the root cause of my failures. incorporated the yves fix, and that should fix the woodruff key failures. i'll just keep plugging away, and hopefully resolve all issues. my gut feeling is the correct sized poly rods, plus adding a fourth will finally put an end to this fiasco.
 

baz

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good question - i've had more issues with alton and my Mk2 than i care to admit. t've sheared two sprag clutch woodruff keys, and i'm guessing the ploy pin failure was somehow connected to those failures. this last poly pin failure was totally my f-up. i really think there is a compatibility issus between my alton kit and mty 74 commando - what it is, haven't got a clue. i do experience some kickback and backfire, and i did have my original tri-spark failure, and that, i'm thinking, was the root cause of my failures. incorporated the yves fix, and that should fix the woodruff key failures. i'll just keep plugging away, and hopefully resolve all issues. my gut feeling is the correct sized poly rods, plus adding a fourth will finally put an end to this fiasco.
If you are having kickbacks then that is the cause of your problems
And the pins have done their job protecting the sprag clutch
 

maylar

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Any particular reason? I only ask as not too long ago I bought a second Alton starter for my next project bike as I've been so pleased with the first one
Let's see... shear pins, Woodruff keys, Yves' fixes... stuff like that.
I hope you have the best of luck with them. I'll pass.
 
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well, i for one have had my share of problems, but it seems like most folks have years of trouble free service from alton. nobody should base anything on my past experiences. my failures most likely are caused by secondary reasons. i'll sort thru things and life goes on. my alton problems are miniscule compared to my BSA project - 70% through restoratation, and just realized the frame is bent. it's minor, just need to figure out how to fix it without going back to square one. i think i need to walk away from my toys for a while.
 

baz

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Let's see... shear pins, Woodruff keys, Yves' fixes... stuff like that.
I hope you have the best of luck with them. I'll pass.
I'm not sure how many people have had the woodruff key fail out of how many starter kits have been sold so I can't comment on that
The shear pins are a safety fuse designed to shear if there's an issue IE the engine kicking back
So it's not so much of a fault it's doing what it's designed to do if there's a fault elsewhere
I'm hoping my second kit performs as well as the first kit
 
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The shear pins are a safety fuse designed to shear if there's an issue IE the engine kicking back
And the 1975 MK3 had an anti kickback clutch that reset itself after it was set off by a kickback, why did Alton think that self destruction nylon pucks were better.

I have the same anti kickback clutch on my Kawa KLF300 4X4 1989.
 

baz

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And the 1975 MK3 had an anti kickback clutch that reset itself after it was set off by a kickback, why did Alton think that self destruction nylon pucks were better.

I have the same anti kickback clutch on my Kawa KLF300 4X4 1989.
Does the anti kickback clutch work ok on the MK3 ?
 
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Does the anti kickback clutch work ok on the MK3 ?
I don't have a MK3 so can't comment, but it works fine on the KLF300, added to the starter to second years production after a spat of sprag failures. My 89 is on original starter and sprag.
 
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