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Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520320
12/26/13 8:39 pm
12/26/13 8:39 pm
Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
T140V-Rich Offline OP
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T140V-Rich  Offline OP
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Oh, go on, T-man! I wouldn't call myself an expert. smile I'd say I'm a decent reader who can follow instructions. smile But I must admit I found it rather easier than I dreamed it would ever be. You lads told me I could accomplish this task, and now I felt a lot more encouraged to attempt it with your words of wisdom.

I'm waiting on a couple of spares that should be here this weekend. If they arrive, I'll be posting a video of the bike actually running!


1977 T-140V
1973 T-140V
2011 Bonneville SE
Author of "Relics and Reminiscing."
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Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520479
12/28/13 12:55 pm
12/28/13 12:55 pm
Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
T140V-Rich Offline OP
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T140V-Rich  Offline OP
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Posts: 2,000
Sunny South Carolina, (US)
Wanted to give a theory as to why the kickstart drive side nut broke.

The clutch nut goes on at 70 pounds of torque. The kickstart drive side at 45. My theory is that if the kick nut is at 45 pounds intially, any - and I mean any - space will be taken up when the clutch nut is turned home.

My theory is that the extra pressure it takes to wind home the clutch nut is transferred to the kick side nut. Hence, instead of 45 pounds, you wind up with much more than it can stand.

My solution was to simply run home the clutch nut, then the kick nut to a genuine 45 pounds. Button it all up.

I know, laugh me out of the house now. But the breaking point on the mainshaft/nut doesn't appear to be sheared. It simply looks like it was pulled off. Straight out. The clutch nut would be in position to do just that.

Waiting on the mail to close up the clutch side.


1977 T-140V
1973 T-140V
2011 Bonneville SE
Author of "Relics and Reminiscing."
Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520481
12/28/13 1:16 pm
12/28/13 1:16 pm
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
J
John Healy Online content

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John Healy  Online Content

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J
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
OK Rich, slowly turn and step away from that theory.

All of the clutch nut torque is applied to the taper. None, read none, of the torque is transferred through the shaft to the kick starter nut.

The taper needs to be tight to work, so don't skimp on the torque. And don't forget to clean the threads of both the shaft and nuts so they are free from all oil and apply a bit of blue Loctite.


Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520494
12/28/13 4:10 pm
12/28/13 4:10 pm
Joined: Feb 2008
Posts: 4,359
New Jersey USA
Tridentman Offline

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Tridentman  Offline

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Posts: 4,359
New Jersey USA
I agree with John. The torque is transmitted by the clutch taper.
It is vitally important for the taper in the clutch hub and on the mainshaft to fit closely.
Clean thoroughly and make sure there is no burr at the edge of the keyway.
If in doubt LIGHTLY lap the two tapers together using fine grinding paste (as used for valve lapping).
Then clean everything very thoroughly and make sure the nut is damned tight. If you prefer you can leave out the key---the taper does the torque transmission and the tapers are held together by the torque of the clutch nut.
I must admit to being old fashioned--I never put Loctite on the taper--if the fit of the tapers is good then they are difficult enough to get off as it is without being held by Loctite as well.
But--JH is sparing with his Loctite so if he says it is OK then feel free to do it.
HTH

Re: Opening up the gearbox for mainshaft replacement [Re: Tridentman] #520495
12/28/13 4:18 pm
12/28/13 4:18 pm
Joined: Sep 2011
Posts: 984
New Zealand
Excalibur Offline
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Excalibur  Offline
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New Zealand
I think Johns' loctite recommendation is for the thread. The taper should be dry.

Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520498
12/28/13 4:41 pm
12/28/13 4:41 pm
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
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John Healy Online content

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John Healy  Online Content

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J
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
I agree with above - no Loctite on taper, but have always been taught to never lap this type of taper. These tapers are ground and as such have small tears of metal that lapping removes. Grinding does not leave a perfectly smooth surface, but a series of small tears in the metal. Part of the ability for the tapers to lock, and transfer large amounts of toque, is in the tears on the shaft and hub interlocking with each other, not unlike Velcro.

We have discussed this here before and I know Tridentman, and others have another opinion. It is how I was taught in school and it makes perfect sense to me. It is of no offense to me if you have another opinion.


Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520499
12/28/13 4:54 pm
12/28/13 4:54 pm
Joined: Jul 2012
Posts: 1,633
UK Berks
A
AngloBike Offline
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AngloBike  Offline
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UK Berks
completely off topic but a good crystal whisky decanter should have a ground taper in it's neck.
You should be able to slightly twist the stopper and lift the entire decanter aloft by the stopper. That proves the seal is good.

Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520500
12/28/13 5:55 pm
12/28/13 5:55 pm
Joined: Feb 2008
Posts: 4,359
New Jersey USA
Tridentman Offline

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Tridentman  Offline

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New Jersey USA
Yes-John and I agree to disagree on this one.
Even a lapped surface has its mountains and valleys--if you magnify it enough. It is the interlocking of these mountains and valleys ---if held tightly enough together--that provide the transference of torque.
It is surprising if you look at surfaces under an electron microscope---even the most smooth polished surface to the naked eye looks like the Himalayas under the microscope.
I think where John and I do agree is to get the tapers thoroughly clean with no burr on the edge of the keyway and then to make sure that the nut is very tight.
HTH

Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520501
12/28/13 5:56 pm
12/28/13 5:56 pm
Joined: Feb 2008
Posts: 4,359
New Jersey USA
Tridentman Offline

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Tridentman  Offline

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Joined: Feb 2008
Posts: 4,359
New Jersey USA
Yes-John and I agree to disagree on this one.
Even a lapped surface has its mountains and valleys--if you magnify it enough. It is the interlocking of these mountains and valleys ---if held tightly enough together--that provide the transference of torque.
It is surprising if you look at surfaces under an electron microscope---even the most smooth polished surface to the naked eye looks like the Himalayas under the microscope.
I think where John and I do agree is to get the tapers thoroughly clean with no burr on the edge of the keyway and then to make sure that the nut is very tight.
HTH

Re: Opening up the gearbox for mainshaft replacement [Re: AngloBike] #520503
12/28/13 7:16 pm
12/28/13 7:16 pm
Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
T140V-Rich Offline OP
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T140V-Rich  Offline OP
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Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
Originally Posted By: AngloBike
completely off topic but a good crystal whisky decanter should have a ground taper in it's neck.
You should be able to slightly twist the stopper and lift the entire decanter aloft by the stopper. That proves the seal is good.


Are you psychic, Anglo? I just poured scotch into a decanter I received as a gift. Moments ago. Then read your post.

Quite odd. But, here's to your health. smile

I can clearly see the point, and that being the taper absorbs any and all torque received from the clutch nut being turned home.

And no worries, gents. The clutch nut is 70 pounds and the kick side rachet nut, 45 pounds. The grand part is - no breakage! I simply wanted to be absolutely certain I was putting no extra pressure on the kick side rachet nut. And I did that by tightening the clutch nut first.

But the bad news is not all parts arrived in the post today. I'm waiting on two clutch pressure plate thimbles. Another week of waiting.

Today was spent putting the gearside engine bracket back on along with the Trident-style filter, attaching the clutch cable, refilling the gearbox, and tightening the clutch and kick nuts.

Once the thimbles arrive, I can put pressure on the clutch and tighten the rotor nut, button her up and see about getting it cranked again.

Cheers


1977 T-140V
1973 T-140V
2011 Bonneville SE
Author of "Relics and Reminiscing."
Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #520620
12/29/13 3:45 pm
12/29/13 3:45 pm
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
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John Healy Online content

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John Healy  Online Content

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J
Joined: Mar 2005
Posts: 10,156
Boston, Massachusetts
One of the things you must consider about the taper is the surfaces themselves are hard, but the metal under the surface hardening is quite malleable. Even slight deviations from a perfect taper will mold as the pressure to the joint is applied. This is just one reason to tighten the nut holding a taper, properly.

An ever so light coat machinist "blue" applied to the surfaces, and a "single "twist" of the hub on the shaft (no key installed), will expose any imperfections. It has been my experience that any shaft that does not display a decent taper, or one that has failed previously, and is being lapped trying to remove any galling, will not hold if stressed.


Re: Opening up the gearbox for mainshaft replacement [Re: T140V-Rich] #521593
01/05/14 8:32 pm
01/05/14 8:32 pm
Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
T140V-Rich Offline OP
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T140V-Rich  Offline OP
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Joined: Sep 2005
Posts: 2,000
Sunny South Carolina, (US)
Re-checked the torque settings on the nuts and installed the pressure plate.

Do I have the pressure plate adjuster nuts too tight if the clutch won't disengage when I push the kickstart down? I've backed the adjuster nuts out somewhat but the clutch hasn't disengaged when the lever is pulled.

This one has fought the entire way, and is trying again.

Oh, someone asked, I think. 1973 T140.


1977 T-140V
1973 T-140V
2011 Bonneville SE
Author of "Relics and Reminiscing."
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