Author Topic: Anybody with Twenty One / 3TA experience?  (Read 34148 times)

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #30 on: August 12, 2013, 06:30:36 PM »
"Another thing to think about is what sliding/rolling surfaces resist the clutch springs when the clutch is disengaged. As far as I can see it's the clutch basket flange pushing against the central hub through the rollers"................ can you explain this in more detail please im not sure what your trying to say

Offline antoni

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Re: Anybody with Twenty One / 3TA experience?
« Reply #31 on: August 12, 2013, 07:43:42 PM »
"Another thing to think about is what sliding/rolling surfaces resist the clutch springs when the clutch is disengaged. As far as I can see it's the clutch basket flange pushing against the central hub through the rollers"................ can you explain this in more detail please im not sure what your trying to say

It's a bit difficult to get your head around but just had another go.

When the clutch is engaged it just sits on the mainshaft and transmits torque to it, with or without wobble. All parts of the clutch are rotating at the same speed, which is the same as saying no parts are rotating with respect to each other. So there's no worry about anything wearing against anything else.

When disengaged, the clutch parts are not only rotating at different speeds, but the push-rod is pushing the clutch assembly 'outboard' of the bike, creating a side force.

Of course the side force is your left hand against the clutch springs. Consider what the path of that force is.

The pushrod pushes the clutch pressure plate outboard and compresses the springs (from the inside). The springs respond by pushing on the slotted spring adjuster nuts, which pull their bolts. The bolts pull on the clutch hub. What restrains the clutch hub? It's the tight main nut pulling the hub against the clutch flange, and in so doing holding thee clutch flange firmly onto the mainshaft.

So the basket doesn't take part in procedings. It doesn't have to handle any side force against its guides, only rotating radial force, handled by the rolllers.

Thanks to Wetdog for forcing me to think about it more carefully. I only worked out there's no problem with side force writing this! And there are the spiral wear marks on the inside of the hub - I was at work and couldn't look at it when I wrote the last post.

Rock's still there tho...

Offline chaterlea25

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Re: Anybody with Twenty One / 3TA experience?
« Reply #32 on: August 12, 2013, 10:19:30 PM »
Hi Antoni
The picture shows the roller bearing almost to the end of the bearing surface, this is correct
The "hub" which fits over the splines should fit against the roller race shoulder
It sounds to me as if the "thick washer" that fits in before the nut is missing, this washer is about 5mm thick and holds the hub against the shoulder and the nut locks everything solid
In your case it seems the nut is holding the shaft adaptor and not the hub
If the inside spider of the hub shock absorber is worn where it fits against the roller race it can lead to the clutch locking up when the nut is tightened  >:(

HTH
John

Offline antoni

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Re: Anybody with Twenty One / 3TA experience?
« Reply #33 on: August 12, 2013, 10:46:47 PM »
Hi Antoni
The picture shows the roller bearing almost to the end of the bearing surface, this is correct
The "hub" which fits over the splines should fit against the roller race shoulder
It sounds to me as if the "thick washer" that fits in before the nut is missing

 ...snip....
.

John, thanks for the input.

Anyone, thanks for input.

That cup-washer (think that's what the books call it) is present. So the nut does act through it onto the splines of the mainshaft flange, the hub being trapped in the 'spline-space' hope you can see what I mean.

The inboard surface of the shock-absorbing hub is indeed acting against the shoulders of the rollers. Unfortunately, for whatever reason, there's 30th end float for the rollers, and significantly the clutch basket flange, to rattle around in.



 

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #34 on: August 13, 2013, 09:50:35 AM »
interesting , ive just measured my 1958 clutch basket , from the out side edge of the teeth to the edge of the basket its 22 and 1/2 mm ...... but looking at the primary cover (no tentioner type ) it looks a bit shallower over the clutch compared to my later t100 primary cover , but you have the latter primary so don't think its a case of shallow type primary , also the basket would not wobble unless it hits something when spinning (in this case the outter cover ) , all said I would try a roller thrust shim ............... mine is also a 4 spring type and I have fitted roller thrust shim (twice as it did ware one out ? )
« Last Edit: August 13, 2013, 12:29:24 PM by wetdog »

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #35 on: August 13, 2013, 12:25:39 PM »
one other thing , you say the chain lines up , but the crank nut looks to be a way out off the end of the crank  , has some one spaced the crank sprocket out ?

Offline antoni

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Re: Anybody with Twenty One / 3TA experience?
« Reply #36 on: August 13, 2013, 01:53:02 PM »
Hello Wetdog,

The dimension you gave, not sure what it refers to. Do you mean that if you laid the basket flat on a table it would be 22.5mm high?

Anyone know how thick the shim is? 28th by any chance?

BTW, I haven't shown a picture of my crank - the pic in post 19 is someone else's bike. The sprockets line up and the chain run path looks sensible. I have the earliest primary chain case cover with the vertical oil drain. It fits the unit-engine properly. Someone has retrofitted a chain tensioner, I'm minded to leave it out as it has a new chain and has none of the droop visible in the earlier picture (yet).

Just spoke to 'Tri-Supply', he said there should be no shim at the rollers on a four spring clutch, and that all bikes were fitted with 4 spring up to the 60s. He's sending me some ~6mm by quarter rollers, but had been thinking he was selling quarter by quarter until he measured them. He didn't offer any opinion on why the clutch rocks. He said there should be a bit of rock. Did he say 1/8th? Mine's more like 3/8ths - 1/2 inch.

I'm getting closer to attacking things with a lathe....
« Last Edit: August 13, 2013, 04:45:21 PM by antoni »

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #37 on: August 13, 2013, 06:58:51 PM »
"Someone has retrofitted a chain tensioner" .... how ? the later chain tentioner needs the latter primary so how is it you still have the early cover ? the 22half is with the basket fitted measure with a rule butted up against the teeth on the basket to the edge of the same . the early cover with no tentioner looks shallower to me , but cannot be 100% as the t100 one is still fitted to the bike , im wondering if they made the clutch basket wider for some reson , can you post a pic of your retro fitted tentioner thanks ( ps they did make alloy barrels for 3ta )
« Last Edit: August 14, 2013, 09:03:34 AM by wetdog »

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #38 on: August 14, 2013, 09:17:23 AM »
"He's sending me some ~6mm by quarter rollers" ................. just read this again , if you have 1/4 .1/4 rollers now and fit 1/4 ,6mm wont this make it worse ?

Offline antoni

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Re: Anybody with Twenty One / 3TA experience?
« Reply #39 on: August 14, 2013, 09:57:12 AM »
"He's sending me some ~6mm by quarter rollers" ................. just read this again , if you have 1/4 .1/4 rollers now and fit 1/4 ,6mm wont this make it worse ?

Yes. My quarter-wide rollers are currently improving the symptom very slightly, but I want to fix the problem.

I'll photograph the tensioner set-up as it was at disassembly. It's clearly wrong because the adjuster screw fouls on the bottom of the primary case.

I'll compare that dimension you gave with mine when I go back into the shed.

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #40 on: August 14, 2013, 10:29:40 AM »
I really need to pay more attention this early alloy barrelled 3ta I have here (vertical drain etc) has a chain tentioner fitted , but can only be accessed when the outer shallow cover is removed ( how I missed this I don't know) unlike the t100 which can be accessed via the oil drain so no need to take primary off , does yours look like this im not sure if this is a retro fit or original , the clutch does not rock
« Last Edit: August 14, 2013, 10:32:40 AM by wetdog »

Offline Rex

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Re: Anybody with Twenty One / 3TA experience?
« Reply #41 on: August 14, 2013, 02:04:51 PM »

[
Yes. My quarter-wide rollers are currently improving the symptom very slightly, but I want to fix the problem.

All those roller are 1/4" wide (diameter) but genuine Triumph ones are 17 thou shorter in length. Anyone actually asking for 1/4 X 6mm rollers should raise a hearty laugh at the suppliers anyway... ;)


Offline antoni

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Re: Anybody with Twenty One / 3TA experience?
« Reply #42 on: August 14, 2013, 03:03:10 PM »
Interesting size naming convention you're using there Rex!

The supplier did not know that the rollers he has been selling were quarter by approx 6mm. Only after I asked him to measure them did he realise what he had - with some embarrassment I think.

I don't see anything wrong with mixing metric and non-metric if it's convenient and clear.

The works warehouse floor is marked with metres and cubits.

Offline Rex

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Re: Anybody with Twenty One / 3TA experience?
« Reply #43 on: August 14, 2013, 04:37:52 PM »
I'm not using it, but quoting it from the previous posts.

It's just daft to mix units like this. It's like the DiYer who asks the timber merchant for 2 metres of 4X2, or the nut and bolt stockist for M6    by 2" set screws usually  to much hilarity from the staff... ie it's laughable in any mathematical or engineering context.

More seriously Triumph didn't make 1/4 X 6mm rollers, they made 0.250 x 0.234 rollers. Nothing to do with 6mm, ever.

wetdog

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Re: Anybody with Twenty One / 3TA experience?
« Reply #44 on: August 14, 2013, 04:47:47 PM »
4 by 2 is sold by the meter , bad example , but I do know what you mean