Author Topic: 1975 CB750 Restoration  (Read 4083 times)

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Offline derbydave

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1975 CB750 Restoration
« on: April 14, 2017, 10:22:00 AM »
I recently purchased a non running 1975 CB750 for $250.  I plan to restore it as close to original as possible. There are a few missing and broken parts but it is mostly all there.  Should be a fun project.










« Last Edit: April 28, 2017, 02:57:32 PM by derbydave »
1975 Honda CB750
2003 Suzuki GZ250

Offline SOHC4 Cafe Racer Fan

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Re: 1974 CB750 Restoration
« Reply #1 on: April 14, 2017, 10:24:15 AM »
Nice buy especially if it has a title.

Is the motor free or seized? 
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 derbydave

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Re: 1974 CB750 Restoration
« Reply #2 on: April 14, 2017, 10:27:04 AM »
Motor is seized and no Title (yet).  In KS the bike qualifies as an antique which allows me to get a title with just a bill of sale and VIN inspection.
1975 Honda CB750
2003 Suzuki GZ250

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Re: 1974 CB750 Restoration
« Reply #3 on: April 14, 2017, 11:34:08 AM »
In KS the bike qualifies as an antique which allows me to get a title with just a bill of sale and VIN inspection.

That's a plus. 

I'm sure calj737 will chime in on his "cocktail" for freeing up a seized motor.
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 CycleRanger

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Re: 1974 CB750 Restoration
« Reply #4 on: April 14, 2017, 08:58:09 PM »
Looks like you have a good candidate there!  :)
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline Jnel

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Re: 1974 CB750 Restoration
« Reply #5 on: April 15, 2017, 08:27:02 AM »
Marvel mistery oil and #2 fuel oil.  Fill the cylinder thru the plugs holes.  Let it sit for as long as you can. Keep topping it off. This worked for me on several occasions.   Be patient.  Try to turn it by hand.  Both ways.

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Offline Stev-o

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Re: 1974 CB750 Restoration
« Reply #6 on: April 15, 2017, 08:49:02 AM »
Marvel mistery oil and #2 fuel oil.  Fill the cylinder thru the plugs holes.  Let it sit for as long as you can. Keep topping it off.



Or ATF/acetone....worked for me.  After setting a few days, put in 3rd gear and rock it back and forth.   Had a 17' long geyser shoot out of it, set the record!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Jnel

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Re: 1974 CB750 Restoration
« Reply #7 on: April 15, 2017, 01:22:40 PM »
Yes, this is not a indoors sport. Definitely do the final move outsid. Don't forget your safety gear, and do a JSEA pror to starting the job.

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Offline derbydave

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Re: 1974 CB750 Restoration
« Reply #8 on: April 25, 2017, 07:34:49 PM »
I got the engine freed up this evening.  I took the stator cover off and used my breaker bar on the end of the crank to rock it back and forth until it freed up.  Didn't take near as much as I was expecting.
1975 Honda CB750
2003 Suzuki GZ250

Offline Stev-o

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Re: 1974 CB750 Restoration
« Reply #9 on: April 25, 2017, 08:41:42 PM »
Good news
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline calj737

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Re: 1974 CB750 Restoration
« Reply #10 on: April 26, 2017, 04:42:02 AM »
It would still be wise to pour a cocktail down the plug holes to eat away at the rust that accumulated in the cylinders (if you didn't).

Don't know your full plans for the restoration, but member Noblehops (Nils) runs RestoCycle and provides a vapor blasting service to restore your engine cases and carbs and hubs to an immaculate level of beauty!
https://www.restocycle.com

Many members have used his service and none have regretted it  :D
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline derbydave

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Re: 1974 CB750 Restoration
« Reply #11 on: April 26, 2017, 07:10:46 AM »
I put PB Blaster in the cylinders when I first got the bike.  I will probably add some MMO later.  Since I am planning a full restoration the engine is going to come out of the frame and get a full inspection and a rebuild if the inspection warrants it.
1975 Honda CB750
2003 Suzuki GZ250

Offline Jnel

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Re: 1974 CB750 Restoration
« Reply #12 on: April 26, 2017, 07:50:26 AM »
Good job.  What was the mixture you went with?  PB Blaster alone?

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Offline derbydave

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Re: 1974 CB750 Restoration
« Reply #13 on: April 26, 2017, 07:53:11 AM »
Yup, just straight PB Blaster.
1975 Honda CB750
2003 Suzuki GZ250

Offline derbydave

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Re: 1974 CB750 Restoration
« Reply #14 on: April 26, 2017, 07:38:30 PM »
My Honda loaded in the back of my Honda ready to go get a VIN inspection tomorrow and hopefully an antique title.

« Last Edit: April 26, 2017, 07:42:53 PM by derbydave »
1975 Honda CB750
2003 Suzuki GZ250

Offline derbydave

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Re: 1975 CB750 Restoration
« Reply #15 on: April 28, 2017, 03:00:20 PM »
So when I went to get my VIN inspection I found out that my 74 is really a 75.  I was unaware that despite the 7/74 build date it is considered a 75 Model year.  Whoops
1975 Honda CB750
2003 Suzuki GZ250

Offline Stev-o

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Re: 1975 CB750 Restoration
« Reply #16 on: April 28, 2017, 03:56:10 PM »
So when I went to get my VIN inspection I found out that my 74 is really a 75.  I was unaware that despite the 7/74 build date it is considered a 75 Model year.  Whoops

Hodel didnt use "model years", you either have a K4 or a K5, the VIN will help you determine that.

Now, you could have had a K4 built in '74 but was sold and titled in 1975, with a title stating it's a '75.     Got it?!

'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline derbydave

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Re: 1975 CB750 Restoration
« Reply #17 on: April 28, 2017, 04:22:19 PM »
It is a K5.  I did some research and looked up the model differences.  The turn signals, indicator light panel, and rubber tipped kickstand are all K5  :D  That being said Kansas designates it a 1975 since it was built after May 74
1975 Honda CB750
2003 Suzuki GZ250

Offline Tews19

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Re: 1975 CB750 Restoration
« Reply #18 on: May 01, 2017, 04:14:58 PM »
Subscribed
1969 Honda CB750... Basket case
1970 Honda CB750 survivor.

Offline derbydave

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Re: 1975 CB750 Restoration
« Reply #19 on: May 10, 2017, 02:44:16 PM »
The bike is no longer Titleless.  I successfully got my Antique title today from the DMV.  The lady doing the title work gave me a funny look when I didn't have the original title for the bike but with some help from a supervisor and after looking up the antique title rules (which I printed just in case) all was good.  She said hey I learned something today.  :)  I can begin the real work now that all the paperwork is out of the way.
1975 Honda CB750
2003 Suzuki GZ250

Offline Stev-o

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Re: 1975 CB750 Restoration
« Reply #20 on: May 10, 2017, 04:33:28 PM »
What is an "antique title"?

I've made them scratch their heads and grab the big book before too!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline derbydave

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Re: 1975 CB750 Restoration
« Reply #21 on: May 10, 2017, 05:26:35 PM »
Antique titles and the associated plates are a special class of registration reserved for vehicles 35 years or older in Kansas.  The vehicles major components must be from the same model and vintage for the year of the vehicle,  for example a modern drive train installed in an antique body or frame does not qualify.  The upside is the taxes are only $17.00 per year and I get a special antique plate when I put it on the road or I can use a plate from 1975 and register the plate so I can legally display the period correct plate.
1975 Honda CB750
2003 Suzuki GZ250