New Layshaft

[shamrockexpress]

is there any reason not to use original italian ones?

[dscscotty]

We've (Team DSC) had one on test all last season in our 40bhp group 6, finished 2nd overall in both group 6 and overall championship, no issues and immaculate on all pre/post race checks, if Steve cant break it usually means they're good!

[rossclark]

is there any reason not to use original italian ones?

Yes

They're minimum 50 years old and who knows what abuse they've had over the years.

[shamrockexpress]

is there any reason not to use original italian ones?

Yes

They're minimum 50 years old and who knows what abuse they've had over the years.

so is the casing that the whole engine is relying on and alloy isnt as hard and long lasting as steel!!!!!
anyway its everyones own decision what they trust i suppose.

[dscscotty]

Snapped layshafts are more common than you think, here's 3 just in past few yrs, plus I know of several others, each one tells a heart pumping, arse clenching tale!



photo sharing

[shamrockexpress]

cant argue with that,,,,,,,,,innocenti paper weights lol

[Fast n Furious]

I've never tried it, but often wondered how well these broken shafts could be recovered by drilling out the center and tapping out to M16 fine. Then use a high tensile steel setscrew to secure the taper locking of the hub instead of a nut? The bolt could then be easily replaced periodically before structural fatigue sets in? It would make getting the hub off with the wheel much easier.
The steel hardness might be an issue?

[Nudger]

This sort of failure is more common than people think.
With quality replacements on the market why take the risk?

[Nudger]

Bloody photo hosting @&^%£*'ers

[Scooterdude]

My AF one has just landed, got to say it looks very well made and nicely finished. I’ll report back if it won’t fit

[Scooterdude]

Is there any reason why my new AF layshaft is completely different to the original one I’ve just taken out?

[ToBoldlyGo]

Yes, the thicker one on the left is generally used in the S2. Whereas the one on the right is a standard S3. But there is no guarantee that the earlier one wasn't used in later models. So it's just rule of thumb.

[Scooterdude]

Yes, the thicker one on the left is generally used in the S2. Whereas the one on the right is a standard S3. But there is no guarantee that the earlier one wasn't used in later models. So it's just rule of thumb.

Ok thanks, I looked in my Stickies book but couldn’t see any reference made to it, mine’s s3 1964 btw.

[rossclark]

cant argue with that,,,,,,,,,innocenti paper weights lol

The casing isn't really 'loaded' in the same way as parts like the layshaft - the casing is equally susceptible to kak-handedness but in different ways - stripping a thread is not the end of the world. Layshafts are subject to repeated 'torqueing' of the hub nut, often with a length of scaffold pole, or similar, stressing the metal and leading to the failures you see above. The stress placed into the steel doesn't always lead to an immediate failure, it is cumulative and will eventually lead to weak points being exposed with potentially life threatening consequences.

[Warkton Tornado No.1]

is there any reason not to use original italian ones?

This issue of "New versus Old" has been raised before & TBH, & it's fair to say no decisive action has been taken to address the concerns within the debate.

It amounts to "New (but uncertified materials, manufacturing methods, quality processes/inspection & transportation/storage care)" versus "Old [in the case of OEM] (but no means of quantifying age related stresses)"

As far as I am aware (& I stand to be corrected) those OEM layshafts that have failed have had assumptions made as to the reason why. It's all very well to speculate why a layshaft can fail, but I would argue that it cannot be put down to age. Otherwise, WW2 aircraft & the like would never be allowed to fly.

That said, virtually all old planes & Motorsport vehicles will have to conform to some kind of worthiness certification, right down to each safety critical component.

'We' (as a large owner enthusiast club) do not apply those principles adopted by other organisations, & I personally would prefer it if we did.

I'm not looking to add fuel to any argument, but this is an emotive subject.

I believe there is an amount of naivety in both camps.

If it were feasible to source an absolutely unused NOS (New Old Stock) layshaft & compare it with one of the pattern/'upgraded' replicas in testing (destructive if need be) then the results would be able to speak for themselves.

Until then, any evidence is largely anecdotal.

I hope nobody believe that I am out to p*ss on their chips, but surely many of us have by now been caught out with the presumption of "new being better?"

It is a fact of life that copies are rarely as good as the originals, with very few exceptions.

It's not just layshafts that need to be thought about, though some replacement components are more obviously a safety issue to some of us. For instance. Layshaft bearings with ball-cages that are 'popped in' during construction can so very easily 'pop out' again. Premium rear shock absorbers have been dangerous. Heavy duty disc brake cables have failed. Tubeless rims have been proven unsafe.

Even rear hubs can fail, including NOS OEM 'Innocenti' hubs that collapse, as has happened to many of us during the rigours of racing. That's why Serveta rear hubs are prized, but even the OEM Innocenti hubs are designed to 'fail safely', that is, collapse inwardly toward the gearbox, rather than outwardly. Still a b@stard to control, mind you, then push back to the pits. Do you know just how safe your modern pattern rear hub is? It may not have failed, but if it does, do you have the assurance that it will fail as it should? I don't care how many have been sold & are in use. That's not proof of fitness for purpose.

[Scooterdude]

is there any reason not to use original italian ones?

This issue of "New versus Old" has been raised before & TBH, & it's fair to say no decisive action has been taken to address the concerns within the debate.

It amounts to "New (but uncertified materials, manufacturing methods, quality processes/inspection & transportation/storage care)" versus "Old [in the case of OEM] (but no means of quantifying age related stresses)"

As far as I am aware (& I stand to be corrected) those OEM layshafts that have failed have had assumptions made as to the reason why. It's all very well to speculate why a layshaft can fail, but I would argue that it cannot be put down to age. Otherwise, WW2 aircraft & the like would never be allowed to fly.

That said, virtually all old planes & Motorsport vehicles will have to conform to some kind of worthiness certification, right down to each safety critical component.

'We' (as a large owner enthusiast club) do not apply those principles adopted by other organisations, & I personally would prefer it if we did.

I'm not looking to add fuel to any argument, but this is an emotive subject.

I believe there is an amount of naivety in both camps.

If it were feasible to source an absolutely unused NOS (New Old Stock) layshaft & compare it with one of the pattern/'upgraded' replicas in testing (destructive if need be) then the results would be able to speak for themselves.

Until then, any evidence is largely anecdotal.

I hope nobody believe that I am out to p*ss on their chips, but surely many of us have by now been caught out with the presumption of "new being better?"

It is a fact of life that copies are rarely as good as the originals, with very few exceptions.

It's not just layshafts that need to be thought about, though some replacement components are more obviously a safety issue to some of us. For instance. Layshaft bearings with ball-cages that are 'popped in' during construction can so very easily 'pop out' again. Premium rear shock absorbers have been dangerous. Heavy duty disc brake cables have failed. Tubeless rims have been proven unsafe.

Even rear hubs can fail, including NOS OEM 'Innocenti' hubs that collapse, as has happened to many of us during the rigours of racing. That's why Serveta rear hubs are prized, but even the OEM Innocenti hubs are designed to 'fail safely', that is, collapse inwardly toward the gearbox, rather than outwardly. Still a b@stard to control, mind you, then push back to the pits. Do you know just how safe your modern pattern rear hub is? It may not have failed, but if it does, do you have the assurance that it will fail as it should? I don't care how many have been sold & are in use. That's not proof of fitness for purpose.

I suppose that in my case my big saving grace would be if the original layshaft failed whilst out I’m basically up the creek without a paddle, on the other hand however if my new AF one was to fail I would fully expect full recompense from AF not only to cover the layshaft but also other damage caused to the scooter as a result of their product failing.

[dscscotty]

If nothing else, at least a new one will not have had 50yrs of abuse, and been under severe stress due to being over the recommended torque settings, despite whats been relayed I've seen 40+bhp put through new type layshafts, under very hard circuit racing and endurance racing and not had a failure in 5yrs, for me thats enough.

[Warkton Tornado No.1]

is there any reason not to use original italian ones?

This issue of "New versus Old" has been raised before & TBH, & it's fair to say no decisive action has been taken to address the concerns within the debate.

It amounts to "New (but uncertified materials, manufacturing methods, quality processes/inspection & transportation/storage care)" versus "Old [in the case of OEM] (but no means of quantifying age related stresses)"

As far as I am aware (& I stand to be corrected) those OEM layshafts that have failed have had assumptions made as to the reason why. It's all very well to speculate why a layshaft can fail, but I would argue that it cannot be put down to age. Otherwise, WW2 aircraft & the like would never be allowed to fly.

That said, virtually all old planes & Motorsport vehicles will have to conform to some kind of worthiness certification, right down to each safety critical component.

'We' (as a large owner enthusiast club) do not apply those principles adopted by other organisations, & I personally would prefer it if we did.

I'm not looking to add fuel to any argument, but this is an emotive subject.

I believe there is an amount of naivety in both camps.

If it were feasible to source an absolutely unused NOS (New Old Stock) layshaft & compare it with one of the pattern/'upgraded' replicas in testing (destructive if need be) then the results would be able to speak for themselves.

Until then, any evidence is largely anecdotal.

I hope nobody believe that I am out to p*ss on their chips, but surely many of us have by now been caught out with the presumption of "new being better?"

It is a fact of life that copies are rarely as good as the originals, with very few exceptions.

It's not just layshafts that need to be thought about, though some replacement components are more obviously a safety issue to some of us. For instance. Layshaft bearings with ball-cages that are 'popped in' during construction can so very easily 'pop out' again. Premium rear shock absorbers have been dangerous. Heavy duty disc brake cables have failed. Tubeless rims have been proven unsafe.

Even rear hubs can fail, including NOS OEM 'Innocenti' hubs that collapse, as has happened to many of us during the rigours of racing. That's why Serveta rear hubs are prized, but even the OEM Innocenti hubs are designed to 'fail safely', that is, collapse inwardly toward the gearbox, rather than outwardly. Still a b@stard to control, mind you, then push back to the pits. Do you know just how safe your modern pattern rear hub is? It may not have failed, but if it does, do you have the assurance that it will fail as it should? I don't care how many have been sold & are in use. That's not proof of fitness for purpose.

I suppose that in my case my big saving grace would be if the original layshaft failed whilst out I’m basically up the creek without a paddle, on the other hand however if my new AF one was to fail I would fully expect full recompense from AF not only to cover the layshaft but also other damage caused to the scooter as a result of their product failing.

I hope that such a scenario ever occurs. However, if it were to happen, I wouldn't bet on winning a case in Court because of the doubts that cannot be disproved. How would you prove "no misuse, correct torque setting, no road pothole impact" etc?

I don't know the solution but without some proof of conformity to OEM specification, faith in a pattern product is no better than using OEM without proving that it remains suitable for use.

[Warkton Tornado No.1]

If nothing else, at least a new one will not have had 50yrs of abuse, and been under severe stress due to being over the recommended torque settings, despite whats been relayed I've seen 40+bhp put through new type layshafts, under very hard circuit racing and endurance racing and not had a failure in 5yrs, for me thats enough.

Equally, there are OEM layshafts that can take such abuse, but my point is that neither you or I are able to prove they are any better, or worse, prior to building into an engine. Nor are we able to do so with the new ones that you advocate.

Your option is not the be all & end all, & I say that with respect.

After all, I know people that have lived to an old age smoking 40 a day, but that doesn't mean it is healthy.

I'm just trying to achieve quantification of the real improvements of new &, more importantly, hoping to achieve some action toward disproving the capability of any existing, OEM layshafts.

[Fast n Furious]

WT1's analogy with WW2 aircraft spells it out really.
Ultimately, these old aircraft get permanently grounded due to metal fatigue of a critical bit that will make it fall out of the sky (Concorde for example).
Those early series 2 shafts would have used the 20 or 11 degree hubs and cones probably, which were torqued up tighter than the series 3 ones. How many times in their 50+ year life have they been relaxed and re-tensioned and were they ever over-tightend? The scaffold bar torque wrench was a very popular tool when we was lads!
As evidence above shows:- you need to assess the risk for yourself based on the published evidence available, How much you value tomorrow, and realising the cost benefit ratio.