Author Topic: 1980 CB650C Build Thread  (Read 1388 times)

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Offline mr-m37hods

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1980 CB650C Build Thread
« on: July 08, 2019, 04:00:45 AM »
Hi all,

I've been holding on to this guy for a while now (something like 4 years). I'm ashamed to say I've been making excuses and/or too broke to dive in.

This is my first thread and my first bike build project, but I have a background in tinkering with cars. This will also be a first for me digging this deep in a motor, so I think it's safe to say expect a lot of mistakes, and questions. I supposed the whole venture could be a frivolous mistake.

I know it's summer and I should be riding by now, but I wanted to further my knowledge and of course, get the ball rolling on this build. I'm going to need some accountability partners  :D.

I'm not against a simple rebuild, but why not put it back together better then it was before? Not looking to go too race-crazy on this build. At the end of the day, I plan to make this mostly a daily driver but would love it to pack a punch.

I promise to try to do my research before asking dumb questions, to be thorough with my work, and listen to the community's wisdom. I hope this might help someone down the line.

Remember this is engine only. So first off thanks, and let's build a sleeper.

TLDR

Plans: A daily with a punch. Carb rebuild. Exhaust TBD. Nothing is really set in stone in terms of the internals, so I'm all ears on suggestions.

Some pictures to come...

EDIT: Changing this to a build thread.
« Last Edit: October 09, 2020, 08:41:53 AM by mr-m37hods »

Offline DaveBarbier

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CB650C Motor Build
« Reply #1 on: July 17, 2019, 06:08:20 AM »
What year? You could always join the few of us with 674cc 650’s :)). If you want to look around in my build thread (link below in my signature) you might get some ideas.

In short, the stock 650 was about 50 horse at the rear wheel. I just dyno’d mine at about 68. It’s a very fun around town bike and it’s quick.

Port work done by MRieck, bored to 674cc with the Dynoman kit, Swain Tech coated pistons, Megacycle 126-20 cam, CR26 specials and a 750/550 Dyna S modified to fit the 650. Fun stuff!

Offline mr-m37hods

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Re: CB650C Motor Build
« Reply #2 on: September 28, 2020, 12:32:16 PM »
1980 here. Your thread is amazing. Much appreciated!

Offline mr-m37hods

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Re: 1980 CB650C Build Thread
« Reply #3 on: October 09, 2020, 08:57:51 AM »
Here’s a photo of her when I just bought her.

Will be back with a back story post shortly :-)

« Last Edit: October 09, 2020, 11:15:05 AM by mr-m37hods »

Offline SOHC4 Cafe Racer Fan

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Re: 1980 CB650C Build Thread
« Reply #4 on: October 09, 2020, 02:02:42 PM »
If you want a less-cruiser and more standard frame, you can swap your 650 motor directly into a 1979 CB650 or any CB550 or CB500 frame.
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: 1980 CB650C Build Thread
« Reply #5 on: October 11, 2020, 02:21:02 PM »
I find the recent interest in the 650 amazing.  Why , it was only a few years ago  , it seems, that there were only a handful of them on this forum . You didn't hear much about them from those who owned one . They knew how to keep a secret. The 650 was the almost  the unknown Honda or the red header stepchild to those familiar with them. It was the the machine that wiped out the 550, the next generation kind of, but it could never take over the 750's place in history,   left in historic limbo must be the reason for it's lack of popularity . I was under the idea that there was so little visible difference (except extra bulkiness and funky wheels).from the 550 to the 79 650 that there was really no point to it, a corporate mistake .The very next year  Honda transformed it to a cruiser style machine bringing the 650 to the mainstream of other of Japanese motorcycle  design of the day leaving behind the tried and true older classic style of the 500/550 and 750 that Honda lovers respected. I wasn't a fan , looked like a Yamaha to me. I bought a 650 by chance a few years back and was sold, I have no complaint about the 650 with one exception,  that is . that some days I want to ride a 650  that doesn't look as bulky as the '79 and not as Yamaha as the '80' version , so the 550/ 650 swap was a perfect solution for me and others here too, the more interest the in the swap, made  more interest to find other ways to make them faster. Reminds me of  60's 70's hot rodding, new ways to upgrade older machines . This is an exciting time for the 650 and it's new owners, because now is the time when you can make one of  these great machines  truly your own. Good luck with your project , they are as fun to build as they are to ride.
« Last Edit: October 11, 2020, 02:24:01 PM by rb550four »
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