Author Topic: CB 550F in a CB 750 frame  (Read 2027 times)

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Offline stevewj

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CB 550F in a CB 750 frame
« on: April 27, 2015, 12:11:03 PM »
Simple question - I have a CB 550 1978 which is great but with a nasty frame
I have seen a CB 750 rolling chassis again 1978 for sale, how similar are the frames ?
How easy would it be to transplant the 550 engine and gearbox into the 750 frame ?

Offline jaguar

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Re: CB 550F in a CB 750 frame
« Reply #1 on: April 27, 2015, 12:16:05 PM »
Easy?
If you have to ask, you probably cant do it.
It isn't a dig, just is what it is.

I don't actually see the point in the swap.
Honda made millions of both.
Just find what you need.

Offline calj737

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Re: CB 550F in a CB 750 frame
« Reply #2 on: April 27, 2015, 12:38:08 PM »
Very difficult to get them to fit. Mounting holes on frames and engine differ greatly. Engines are angled differently to each other. Overall width of 550 is more narrow. Among other things...

I'd think you could source a new frame or refurb yours for far less trouble. What's wrong with your stock 550 frame?
'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 seanbarney41

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Re: CB 550F in a CB 750 frame
« Reply #3 on: April 27, 2015, 01:15:48 PM »
Even if you do manage to get a 550 into the 750 frame, that will not be a fun to ride bike.
If it works good, it looks good...

Offline SOHC4 Cafe Racer Fan

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Re: CB 550F in a CB 750 frame
« Reply #4 on: April 27, 2015, 01:58:39 PM »
The balance and handling is MUCH better with the 550 frame.  If you fabricate new engine mounts for the 750 it will be like sticking a Civic DX engine in a full size sedan.
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 rb550four

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Re: CB 550F in a CB 750 frame
« Reply #5 on: April 27, 2015, 03:30:07 PM »
Most guys want to squeeze a 750 in a 550.
A 550 in a 750 frame would be  a waste of time, money and energy.
A 650 would be a better candidate as the engine should slip right in but I don't know of anyone who has done it, I wouldn't do it unless there were no more 500/550  frames left in the world.
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline Retro Rocket

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Re: CB 550F in a CB 750 frame
« Reply #6 on: April 27, 2015, 03:38:04 PM »
Most guys want to squeeze a 750 in a 550.
A 550 in a 750 frame would be  a waste of time, money and energy.
A 650 would be a better candidate as the engine should slip right in but I don't know of anyone who has done it, I wouldn't do it unless there were no more 500/550  frames left in the world.

I'd throw a 650 engine into a 550/500 frame....There, I think we have everything covered now.... ;D ;D ;)
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline SOHC4 Cafe Racer Fan

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Re: CB 550F in a CB 750 frame
« Reply #7 on: April 27, 2015, 06:13:41 PM »
Me too!   ;D
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 stevewj

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Re: CB 550F in a CB 750 frame
« Reply #8 on: April 30, 2015, 11:34:02 AM »
So... That's a no then
Thanks guys !

Offline stevewj

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Re: CB 550F in a CB 750 frame
« Reply #9 on: April 30, 2015, 11:36:45 AM »
Think I'll sell it and start a new search when I reach Mallorca.
Anyone know any classic bike guys on the island ?

Offline SOHC4 Cafe Racer Fan

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Re: CB 550F in a CB 750 frame
« Reply #10 on: April 30, 2015, 11:55:52 AM »
Make a stop in Jerez this weekend for the MotoGP race on Sunday. 
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 stevewj

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Re: CB 550F in a CB 750 frame
« Reply #11 on: April 30, 2015, 12:53:40 PM »
Not going til the 28th May lol

Offline SOHC4 Cafe Racer Fan

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Re: CB 550F in a CB 750 frame
« Reply #12 on: April 30, 2015, 01:50:19 PM »
If you are still there in Mid June, go to the Catalunya GP on June 14.  Or, you could divert to Portigal to see World Superbike racing at Portimao on June 7!
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