Author Topic: CB500 Four K1 1972, currently mid mono-shock, working on engine  (Read 8004 times)

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #25 on: January 13, 2019, 04:46:06 am »
Waiting on rebore.

Built these   

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #26 on: January 27, 2019, 03:09:09 am »
I could use a bit of help please.

To allow the twin calliper/disc set up I bought some 1975 CB550 SS forks (the blue ones).

Having stripped both the original 1972 500 K1 and the 550 forks, there are the following differences.

500 tubes are about 7mm longer than 550.

500 internals have a continuous rod through the spring.

I need to combine the 500 (longer) tubes (as the 550 are shot) with the 550 sleeves for dual callipers.

Questions.

Are the 550 internals an upgrade?

If so will the extra 500 tube length be a problem?

Or, do I use the 500 internals with the 550 sleeves?

Any thoughts?

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #27 on: January 27, 2019, 03:11:22 am »
With photos

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #28 on: January 27, 2019, 03:16:58 am »
photos

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #29 on: January 27, 2019, 03:18:20 am »
Photo

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #30 on: January 27, 2019, 03:29:43 am »
Photo

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #31 on: February 11, 2019, 03:15:14 am »
Only combination that worked was 500 parts in 550 outer.
All good just need to fit oil seals and refill.
Any thoughts on callipers behind the fork legs?

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #32 on: November 23, 2019, 06:05:18 am »
Long time but a quick update and hope to share the rebuild bits from here on.

Just back from powder coat.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #33 on: December 08, 2019, 08:54:59 am »
Finally started reassembly.

Steering and engine.

Lay the engine on its side, lowered the frame over. Long bolts first. No scratches, no problem.



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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #34 on: December 14, 2019, 08:59:58 am »
I’m sure it’s been asked a thousand time but, which way up do these fork seals go?

First photo has a few numbers/letters on the upper surface. 

Second photo has no letters on upper surface.

There is a projecting ridge on the outside of the no letters’ surface - photo three.

I.e. the seal has a slightly larger external diameter at the surface with no letters on.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #35 on: December 15, 2019, 11:47:55 am »
Made some progress.
Fitted the mono-shock swing arm. Not everyone’s taste but works for me.
Fitted the fork seals using a short piece of plastic plumbing pipe. Could not have been easier.
Circlips and boots and the forks look terrific.
Reversed the forks so the callipers will go behind for twin disc set up.
Need to work out ugly relationship between brake cylinder/piston and clip on mount.
Otherwise all good.
I think.
« Last Edit: December 15, 2019, 12:10:38 pm by Register »

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #36 on: December 15, 2019, 11:51:49 am »
A few photos

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #37 on: December 15, 2019, 11:59:05 am »
And the forks.
Piece of plastic plumbing pipe made installing the fork seals really easy - letters upwards seems to be the way.
Fork sliders reversed for callipers behind for the twin disc set up.
Need to sort out the master cylinder to clip-on mounting, as currently the brake lever angle means a very bent wrist.
Otherwise all good.
I think.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #38 on: December 18, 2019, 03:59:25 pm »
Wow, that looked painful.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #39 on: December 18, 2019, 10:36:13 pm »
yep, those twin shocks didn't know what hit them.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #40 on: December 22, 2019, 12:28:02 pm »
Made a bit of of progress - now rolling.
Rather wish I’d gone for black rear sets however.
One for later.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #41 on: December 23, 2019, 08:45:02 am »
Cut the bars to length, fitted the kick stand, cut some 0.090 washers for top yoke bolts.
Sat on it and made noises.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #42 on: December 23, 2019, 08:46:57 am »
Photos

Offline Korven

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #43 on: December 29, 2019, 03:09:39 am »
Woah, your making great progress. Not sure if im into monoshocks or not, i mean on Sportsbikes they arent that visible.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #44 on: December 31, 2019, 10:19:36 am »
Took forever to fit the calipers behind the forks.
Had to machine 2mm off the larger mount to get pads to align with the disc.
Finally got everything sorted with free spinning wheel.
Need to flip the mudguard mount or work out a fork brace.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #45 on: December 31, 2019, 11:13:50 am »
Tarozzi makes a turn-key fork brace, but that doesn't solve your mudguard issue unless you mount the fender/mudguard directly to the bottom of the fork brace.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline seanbarney41

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #46 on: December 31, 2019, 01:36:23 pm »
Tarozzi makes a turn-key fork brace, but that doesn't solve your mudguard issue unless you mount the fender/mudguard directly to the bottom of the fork brace.
actually,  if he has the forks I think he has, the tarozzi will clear a fender.  It is only the 69-72 750 And 500 forks that have the short lowers which require a very special brace.  Here is a tarrozi with fender on my 750f
If it works good, it looks good...

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #47 on: January 01, 2020, 12:37:48 am »
On the 550s only the 77-78 lowers allow for both fender and brace mounting. I assumed the 500s were the same as the early 550s.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #48 on: January 01, 2020, 04:51:38 am »
Thanks both.
Just spent an endurable hour on a vintage 11 page thread with the believers and doubters of the mudguard 'mounting bracket' v 'fork brace'.
K1 fork tubes, I'll go take a look.

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Re: CB500 Four K1 1972, currently mid mono-shock, working on engine
« Reply #49 on: January 01, 2020, 09:37:47 am »
Looks like this with mudguard mount/brace reversed to suit callipers.
Difficult to know if an aftermarket brace will fit with mudguard.
Also need to weld something into the oversize holes to suit the small bolts if the bracket is to be any use as a brace.