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Author Topic: saving a 1980 KZ750 twin  (Read 67855 times)

Online doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #390 on: Apr 27, 2018, 15:47:45 »
This is for the rear.  I have a nice stainless axle nut that is made out of 316 I would like to use. I was a little worried about welding dissimilar metals so that's why I was thinking solder as well, but after doing some research I believe using 309L should work fine

Offline jpmobius

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Re: saving a 1980 KZ750 twin
« Reply #391 on: Apr 27, 2018, 17:32:46 »

The parts do not function the same front and back.

Actually they DO end up the same - there are just a few extra parts needed in the front to accommodate the telescoping parts.


By having the bottom of the forks clamp, that is what is stiffening the front end, not having it threaded in or providing force to the underside of the hex cap.  The binding of the forks onto the axle is doing the work.  Notice one end of the axle in the pic does not have a hex bolt.  If it were important to provide force torquing down on that, it would not be designed that way.  Many, many, many axles including my BMW F650 and all modern Suzuki sport bikes are made without a cap at all. 
Here is a VZ800 front end.  The axle is not capped at all.  You thread the axle into the left fork and clamp with the right.  There is zero force squeezing the forks together.  A shoulder on the axle works against the spacers and the bearings keeping the wheel parts tight together, but the fork is separate from that force.


Absolutely agree with all of this!  Evidently my communication skills are as poor as my reading ability.  In all cases, the TENSION in the axle itself is important in keeping all of the various wheel assembly components together.  Having these parts clamped tightly together is fundamental to how stiff this assembly is.  At the rear, the swing arm is part of this assembly, so it gets clamped with all the other bits.  On telescopic forks (99.99% of them anyway), either one of the legs or none of the legs is part of this assembly.  (In the case of one leg incorporated, this in fact IS exactly like the swing arm situation sans one side, which obviously must be fixed independently to prevent fork bind).  Either way, the axle ALWAYS has to provide clamping force.  In the case of one leg being incorporated, it is clamped into the assembly and this clamping force provides the stiffness at the connection.  The other end "floats" in the independent clamp on the other leg until it is tightened and this clamping force provides the stiffness there.  This connection is not on the axle, but on the much larger diameter nut, which, in being previously tightened down with the wheel assembly bits effectively becomes a larger diameter axle.  This of course is the same for assemblies with a nut clamped by BOTH fork legs.  Once the axle assembly is tight, installation into the forks can be accomplished without tweaking the forks out of align.  But the axle itself MUST clamp the wheel components together tightly first in order to maintain the structural strength of the assembly.  That's the point I feel important.  Sorry it took me so long to make it!

Apologies for jacking the thread - I shall work on explaining more clearly on the first pass! (as well as my reading skills!)
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Offline jpmobius

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Re: saving a 1980 KZ750 twin
« Reply #392 on: Apr 27, 2018, 17:45:16 »
This is for the rear.  I have a nice stainless axle nut that is made out of 316 I would like to use. I was a little worried about welding dissimilar metals so that's why I was thinking solder as well, but after doing some research I believe using 309L should work fine

Maybe have a look at 317L if you are determined to make one from stainless.  Should be reasonably easy to get.  That said,  IMHO stainless steels on the whole might not be the best choice for an axle.
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Online doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #393 on: Apr 27, 2018, 20:20:15 »
The axle, I assume, is some type of chromoly. The nut I want weld to it 316 stainless. As far as I can tell ER309L is the preferred filler rod for this application 317 seems to be for dissimilar stainless alloys. I will pin it for added safety, cause I'm a belt-and-suspenders guy when it come to this type of thing. Pro Bolt sells these nuts specifically for motorcycle axles so i can't imagine its too much of a problem.
« Last Edit: Apr 27, 2018, 20:26:27 by doc_rot »

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Re: saving a 1980 KZ750 twin
« Reply #394 on: Apr 28, 2018, 20:32:09 »
Finally had the time to cut and buff the paint. The result is dead flat with no definition line over the stripes. I also put on the badges.Ive been tinkering with the wiring off and on for months and it is finished. I did a bit of driveway tuning learned about the one year specific pilot screws to this year. Rounded up the nessecary parts and it's synced and seems to run great. All that remains to sort is an axle and a license plate. The latter of which should  be here ina week or so.
« Last Edit: Apr 28, 2018, 20:33:42 by doc_rot »

Offline 1fasgsxr

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Re: saving a 1980 KZ750 twin
« Reply #395 on: Apr 28, 2018, 20:42:40 »
I love that green! That's close to the color I was leaning towards on my 1000. Very nice man !!
http://www.dotheton.com/forum/index.php?topic=41083.0

Life is a journey from the maternity ward to the crematorium....

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Re: saving a 1980 KZ750 twin
« Reply #396 on: Apr 28, 2018, 20:55:09 »
Thanks man. It looks even better in the sun

Offline The Jimbonaut

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Re: saving a 1980 KZ750 twin
« Reply #397 on: Apr 28, 2018, 21:18:18 »
Dude.  Just... dude. 

This is glorious.  Skills to pay the bills.  Absolutely terrific looking bike, and that colour!  Doing Kawasaki proud.  Incredible looking bike man, massive kudos. 
"I'm telling you Donnie, nuthin' but nuthin' but right"

Offline CrabsAndCylinders

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Re: saving a 1980 KZ750 twin
« Reply #398 on: Apr 29, 2018, 01:14:28 »
I love that green! That's close to the color I was leaning towards on my 1000. Very nice man !!

I love it too!
Lighter, Quicker, Faster.
ZX-14, 900F x 2, 1100F, R100, CBR600, SR500, GT500, RZ350, KZ1000 x 2, Moto Guzzi Lemans lll, CBX550, RD 350, 750 SOHC police special, RG250, TL1000R, GT750, KTM Super Duke 1290 R, Harris/Z-1, Norton 750 Commando, Green 77 KZ650

Offline The Limey

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Re: saving a 1980 KZ750 twin
« Reply #399 on: Apr 29, 2018, 05:11:56 »
Oh yeah baby.  Bikes on this forum are judged by the turmoil they cause in my Y fronts, the famous brown ones with the orange trim.  Well, I can tell you they're currently stretched to the limit of the elastics ability to contain the swelling beneath, such is the pleasantness of this bike.

At first glance, utterly traditional, but a closer look reveals cleverly integrated modern detailing.  Very cleverly done.  One of my favourite bikes of all time too - Z1easque styling with a brawny, manly, none-of-your-new-fangled-four-cylinder-rubbish-here-son big twin motor.  Love it.  I want this bike soooooo bad.
« Last Edit: Apr 29, 2018, 05:14:59 by The Limey »