clutch slip ?

[isthmus]

hi Adam,thank you for that,I have a few gearbox main shims in my tool box that are just the right size to go behind spring,bonus or what what do you think ,that would suit meo

[Warkton Tornado No.1]

This debate has been a healthy one & Adam, in particular, has really endeavoured to fathom out the problem of why the sprocket cam can override the carrier cam & how to go about correcting it

I still have no idea as to why a shim placed between the oil thrower disc & the splined carrier would affect such overriding, but I’m prepared to believe that it worked in those instances.

However, Adam hit the nail on the head with his reference to SI splined top hat washers which completely obviate the problem by preloading the spring so much more. They are/were highly sought after in the racing World as a consequence.

The strain put through those components causes breakages & a DNF is horrendous

I think we can all take it as read that the main part of this debate is focused upon the cam overriding problem with just a nod to the fact that any modifications should keep in mind the importance of chain alignment....

[isthmus]

[quote="Warkton Tornado No.1"]I hate to appear pedantic, but placing any shim between “the oil thrower washer and under the splined column that it all revolves on” will only have an effect on chain alignment.

To increase ‘cam engagement,’ ‘preload,’ call it what you will, the shimming as stated above will not achieve the desired effect.

The critical dimension of the spring & sprocket assembly is controlled by the splined column & the splined ‘top hat’ washer.

A decrease in that critical dimension may be achieved in a number of ways, but not by shimming between the oil thrower washer and the splined column.

I just wanted to make that crystal clear

[isthmus]

This debate has been a healthy one & Adam, in particular, has really endeavoured to fathom out the problem of why the sprocket cam can override the carrier cam & how to go about correcting it

I still have no idea as to why a shim placed between the oil thrower disc & the splined carrier would affect such overriding, but I’m prepared to believe that it worked in those instances.

However, Adam hit the nail on the head with his reference to SI splined top hat washers which completely obviate the problem by preloading the spring so much more. They are/were highly sought after in the racing World as a consequence.

The strain put through those components causes breakages & a DNF is horrendous

I think we can all take it as read that the main part of this debate is focused upon the cam overriding problem with just a nod to the fact that any modifications should keep in mind the importance of chain alignment....

would you think a gearbox main shim is strong enougth to take the strain of the spring,

[Warkton Tornado No.1]

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:25 am

Warkton Tornado No.1 wrote:
I hate to appear pedantic, but placing any shim between “the oil thrower washer and under the splined column that it all revolves on” will only have an effect on chain alignment.

To increase ‘cam engagement,’ ‘preload,’ call it what you will, the shimming as stated above will not achieve the desired effect.

The critical dimension of the spring & sprocket assembly is controlled by the splined column & the splined ‘top hat’ washer.

A decrease in that critical dimension may be achieved in a number of ways, but not by shimming between the oil thrower washer and the splined column.

I just wanted to make that crystal clear
)(I AM SORRY BUT thats not what you wrote previous !: )Isthmus

Just because I wrote:

“I still have no idea as to why a shim placed between the oil thrower disc & the splined carrier would affect such overriding, but I’m prepared to believe that it worked in those instances”
!

doesn’t mean that I would do it for myself, even if I’m prepared to believe in the integrity of others

I would not attempt a fix in that manner. That may well be ‘my loss’ rather than anybody else’s, but I do attempt to remain civilised & polite .

I’ve said whereabouts I consider shimming should go.

My usual* preference after utilising sprockets & cams that cannot override would be to fit a hard shim/washer/spacer between the sprocket flatish face & the sprocket carrier.

Then, I would be prepared to adjust the chain alignment by shimming appropriately.



As for:

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:53 am

would you think a gearbox main shim is strong enougth to take the strain of the spring,

After sniping @ me earlier (which I can get over if you can ), if you are now asking my opinion of whether the large gearbox shim should be used to preload the spring, I would not do so.

The bore of the large gearbox shim is > Ø35 mm whereas the top cap spigot is < Ø34 mm.

Let’s keep in mind that we are debating how to help one another here by getting around a problem. Essentially, I personally am trying to suggest a smart bodge purely out of good will....

However, remember the * above? As a further testament to my intentions, this is what I would do if I were in your position. You've dragged this knowledge from me that I was hoping to test first @ my own expense:

I would obtain one of my many spare top caps & turn it down so that only the splined portion remained (in other words, a splined spacer)

It should fit snugly in the top cap that I would intend to use.

Ideally, I would then get it brazed into place.

That would then result in a top cap that preloads the spring a lot.

You read it here first....

[isthmus]

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:25 am

Warkton Tornado No.1 wrote:
I hate to appear pedantic, but placing any shim between “the oil thrower washer and under the splined column that it all revolves on” will only have an effect on chain alignment.

To increase ‘cam engagement,’ ‘preload,’ call it what you will, the shimming as stated above will not achieve the desired effect.

The critical dimension of the spring & sprocket assembly is controlled by the splined column & the splined ‘top hat’ washer.

A decrease in that critical dimension may be achieved in a number of ways, but not by shimming between the oil thrower washer and the splined column.

I just wanted to make that crystal clear


Just because I wrote:

“I still have no idea as to why a shim placed between the oil thrower disc & the splined carrier would affect such overriding, but I’m prepared to believe that it worked in those instances”
!

doesn’t mean that I would do it for myself, even if I’m prepared to believe in the integrity of others

I would not attempt a fix in that manner. That may well be ‘my loss’ rather than anybody else’s, but I do attempt to remain civilised & polite .

I’ve said whereabouts I consider shimming should go.

My usual* preference after utilising sprockets & cams that cannot override would be to fit a hard shim/washer/spacer between the sprocket flatish face & the sprocket carrier.

Then, I would be prepared to adjust the chain alignment by shimming appropriately.



As for:

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:53 am

would you think a gearbox main shim is strong enougth to take the strain of the spring,

After sniping @ me earlier (which I can get over if you can ), if you are now asking my opinion of whether the large gearbox shim should be used to preload the spring, I would not do so.

The bore of the large gearbox shim is > Ø35 mm whereas the top cap spigot is < Ø34 mm.

Let’s keep in mind that we are debating how to help one another here by getting around a problem. Essentially, I personally am trying to suggest a smart bodge purely out of good will....

However, remember the * above? As a further testament to my intentions, this is what I would do if I were in your position. You've dragged this knowledge from me that I was hoping to test first @ my own expense:

I would obtain one of my many spare top caps & turn it down so that only the splined portion remained (in other words, a splined spacer)

It should fit snugly in the top cap that I would intend to use.

Ideally, I would then get it brazed into place.

That would then result in a top cap that preloads the spring a lot.

You read it here first....

sorry,I think

[isthmus]

sorry dear friend,I am not about making people look foolish,and I am really sorry for what I did and I hope you will forgive me,I hope we can still be buddies after this,Isthmus ps I am terrible with people and am always a bit much with some

[Warkton Tornado No.1]

No worries.

I hope you get things sorted.

That’s what ‘we’ should be all about.

I’ve tried to find a 34 mm shim that would serve under the top cap on to the spring. The nearest I can get to it is:

M33 Form ‘A’ Flat washer

(which is Ø34 mm bore x 5 mm thick but outside Ø60 mm)

[isthmus]

sorted,i think i,ll put that one down to " how to lose friends and alienate yourself"

[isthmus]

hi Tornado,Adam too,I would agree,brazing onother piece of cap pushing down on the spring,and about the gearbox shim,granted it is slightly larger inner measurement (1mm all round),should not really mater, as when all bolted up it shouldn,t go anywhere,and also I think if you can whack the shim a few times with a club hammer should give us a good idea about its suitability fitted behind the spring.I have also found the clutch basket has slight up and down movement for which I have used another 0.75mm-1mm shim which I slightly modified to fit around spider boss in bottom of the basket,so chain alighnment would then be totally fixed position Isthmus

[Warkton Tornado No.1]

Yet another method, especially for somebody with access to a surface grinder, is to increase spring preload/reduce clearance by grinding material from the top of the splined column, ensuring that the bolt doesn’t bottom out first.

The thing is, somebody else will ask the same thing in a few weeks...

[isthmus]

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:25 am

Warkton Tornado No.1 wrote:
I hate to appear pedantic, but placing any shim between “the oil thrower washer and under the splined column that it all revolves on” will only have an effect on chain alignment.

To increase ‘cam engagement,’ ‘preload,’ call it what you will, the shimming as stated above will not achieve the desired effect.

The critical dimension of the spring & sprocket assembly is controlled by the splined column & the splined ‘top hat’ washer.

A decrease in that critical dimension may be achieved in a number of ways, but not by shimming between the oil thrower washer and the splined column.

I just wanted to make that crystal clear


Just because I wrote:

“I still have no idea as to why a shim placed between the oil thrower disc & the splined carrier would affect such overriding, but I’m prepared to believe that it worked in those instances”
!

doesn’t mean that I would do it for myself, even if I’m prepared to believe in the integrity of others

I would not attempt a fix in that manner. That may well be ‘my loss’ rather than anybody else’s, but I do attempt to remain civilised & polite .

I’ve said whereabouts I consider shimming should go.

My usual* preference after utilising sprockets & cams that cannot override would be to fit a hard shim/washer/spacer between the sprocket flatish face & the sprocket carrier.

Then, I would be prepared to adjust the chain alignment by shimming appropriately.



As for:

Re: clutch slip ?
Post by isthmus » Wed Aug 17, 2016 9:53 am

would you think a gearbox main shim is strong enougth to take the strain of the spring, my[/i][/b] opinion of whether the large gearbox shim should be used to preload the spring, I would not do so.

The bore of the large gearbox shim is > Ø35 mm whereas the top cap spigot is < Ø34 mm.

Let’s keep in mind that we are debating how to help one another here by getting around a problem. Essentially, I personally am trying to suggest a smart bodge purely out of good will....

However, remember the * above? As a further testament to my intentions, this is what I would do if I were in your position. You've dragged this knowledge from me that I was hoping to test first @ my own expense:

I would obtain one of my many spare top caps & turn it down so that only the splined portion remained (in other words, a splined spacer)

It should fit snugly in the top cap that I would intend to use.

Ideally, I would then get it brazed into place.

That would then result in a top cap that preloads the spring a lot.

You read it here first....

[HxPaul]

I would obtain one of my many spare top caps & turn it down so that only the splined portion remained (in other words, a splined spacer)

It should fit snugly in the top cap that I would intend to use.

Ideally, I would then get it brazed into place.

That would then result in a top cap that preloads the spring a lot.

You read it here first.... [/quote]


I agree,that may work,but wont it cover the oil hole in the sprocket sleeve ?

[Warkton Tornado No.1]

Post by HxPaul » Fri Aug 19, 2016 7:34 pm

I agree,that may work,but wont it cover the oil hole in the sprocket sleeve ?

Those two holes, that you call oil holes, will be covered as you say.

Do you know why they are there & their true function?

[HxPaul]

I always thought that it was there to lubricate the bolt,head and thread.

[Warkton Tornado No.1]

Post by HxPaul » Sat Aug 20, 2016 11:37 am

I always thought that it was there to lubricate the bolt,head and thread.

I'm being 'Devil's Advocate' because I don't know for sure, either

However, I reckon that those holes would be simply an escape for any oil that finds it's way into the hollow formed under the bolt head to prevent hydraulic lock. As there is clearance around the splines anyway, plus the thing is not assembled with hands & parts immersed in oil, I'd reckon that they may be a little bit of over-engineering or somewhere to hang the things during the heat treatment processes....

[Adam_Winstone]

These holes may have been solely for the use of the original removal tool, which allows you to get a tight one off with ease. The 2 thub screws locate in these 2 holes for removal.

http://www.lambrettaspares.com/products ... G_2234.jpg

Adam