Topic: CB550 with a CB650 engine: research for future project

[onepieceatatime]

Yes, I appreciate those numbers 'opaat'(onepieceatatime)  Thanks Man.  The 79' CB650 is a lot more like the CB550 and the parts are a closer fit.I want to set one up with round top carbs. When all these parts and pieces do get to me and sitting in front of me,I will begin my assembly.I will need to figure-out what rubber intake manifolds to use on this;I think/hope the airbox rubber boots will connect-up,depending whether I get a CB550-650 eng swap or a 1979 CB650 motorcycle.

I can measure the rubber boots and intake side of the carbs too if you would like. I'll be back at the garage tomorrow.

Sent from my Pixel 4 XL using Tapatalk

[Scott S]

 About halfway down page 4, I start covering the 650 swap. Hurry now and you can see the pics, before Photobucket limits the monthly bandwidth!

http://forums.sohc4.net/index.php/topic,67907.75.html

[grcamna2]

Yes, I appreciate those numbers 'opaat'(onepieceatatime)  Thanks Man.  The 79' CB650 is a lot more like the CB550 and the parts are a closer fit.I want to set one up with round top carbs. When all these parts and pieces do get to me and sitting in front of me,I will begin my assembly.I will need to figure-out what rubber intake manifolds to use on this;I think/hope the airbox rubber boots will connect-up,depending whether I get a CB550-650 eng swap or a 1979 CB650 motorcycle.

I can measure the rubber boots and intake side of the carbs too if you would like. I'll be back at the garage tomorrow.

Sent from my Pixel 4 XL using Tapatalk

Opaat,
Do you have CB650 rubber manifolds for the early head ?

[grcamna2]

About halfway down page 4, I start covering the 650 swap. Hurry now and you can see the pics, before Photobucket limits the monthly bandwidth!

http://forums.sohc4.net/index.php/topic,67907.75.html

Scott S,
I looked(decent pics about to expire,thanks and learned what you and your Father did for the swap.
How did you work out the clearance for the bottom of that header ?

[grcamna2]

The numbers look good  on the 79' CB650;why should I swap a 650 into a 550 when the 79' 650 is good. 
Did you ever own a 79' ? How does it handle compared to the 550 ?

I found in the 550 manual that it’s dry weight is 400lbs. So that’s 30lbs lighter than the 650. So it’s lighter but the difference could easily be made up with a fat rider.

The later cruiser type 650’s are not as easy to turn into a traditional cafe style bike (if that’s what one is doing) so the swap makes sense. If you have an earlier year 650 that runs and rides well then I don’t see a reason to find a 550 to swap the motor into. BUT if you have a 550 that you’re looking to upgrade and come across a 650 parts bike then it’s a no brainer. What I had was a well running 550 and found a 650 for a few hundred bucks. Did the dynoman 674cc big bore kit, megacycle 126-20 cam, MRieck’s stage 2+ porting and CR carbs over a year or two while I was having fun with the 550. Swapped it over a winter and had a 30+ hp increase. It feels good.

Dave,I remember your build  thread and was watching it come together while you built the Patina Hyena.I also liked when you chose to pump-up the engine and wanted to ask,now that you've had a couple years to enjoy the finished product: How do you like the bike and have you been able to keep-up with any other bikes that surprised you? are you glad you did the swap rather than just getting a CB650 ? Can you tell the difference in handling between an early CB650 and the CB550 ?  Thanks,Bill

I love the bike. It still makes me smile when I really give it the beans. As James May would say, it gives me the fizz. I don’t really ride with a lot of other people but I was on a ride with guys with new bikes (not crotch rockets) and I’m right there with them. They were definitely surprised. Getting a 650 wasn’t even a thought, I wanted to do a swap and that’s what I did because I like the aesthetics of my bike. I have never ridden a 650 so I can’t speak to the handling. I imagine the later years didn’t handle as well as the earlier years since they were pretty much a 550 that hit the gym vs a cruise type. Are you veering towards just getting a 650 or still contemplating a swap?

Dave,I hope to see how a fellow member here likes the handling of their 79' CB650.The bike has an inch longer wheelbase than the CB550,was wondering how the rake and trail are different than the 550.

[onepieceatatime]

Yes, I appreciate those numbers 'opaat'(onepieceatatime)  Thanks Man.  The 79' CB650 is a lot more like the CB550 and the parts are a closer fit.I want to set one up with round top carbs. When all these parts and pieces do get to me and sitting in front of me,I will begin my assembly.I will need to figure-out what rubber intake manifolds to use on this;I think/hope the airbox rubber boots will connect-up,depending whether I get a CB550-650 eng swap or a 1979 CB650 motorcycle.

I can measure the rubber boots and intake side of the carbs too if you would like. I'll be back at the garage tomorrow.

Sent from my Pixel 4 XL using Tapatalk

Opaat,
Do you have CB650 rubber manifolds for the early head ?

I have '80 and '81 parts. The '80 engine, carbs, and mount rubbers are the same as the '79. I don't know if the air box and those rubbers are the same though.
I have both models from '80, a complete '81 custom with no title, and 2 incomplete standard model parts bikes, one '80 (engine was blown) and one '81, plus a spare '80 engine.

Sent from my Pixel 4 XL using Tapatalk

[grcamna2]

The 80' have the same airbox as the 79'? Would you see if a pair of round-top CB750 carbs will fit into that if you have the parts ? Thanks 

[Scott S]

About halfway down page 4, I start covering the 650 swap. Hurry now and you can see the pics, before Photobucket limits the monthly bandwidth!

http://forums.sohc4.net/index.php/topic,67907.75.html

Scott S,
I looked(decent pics about to expire,thanks and learned what you and your Father did for the swap.
How did you work out the clearance for the bottom of that header ?

 Honestly, I don't remember. I think I just moved it around as we tightened it up and it cleared.

[onepieceatatime]

The 80' have the same airbox as the 79'? Would you see if a pair of round-top CB750 carbs will fit into that if you have the parts ? Thanks 

I looked up part numbers, '79 and '80 have different part numbers for the airbox and airbox rubbers.

[grcamna2]

The 80' have the same airbox as the 79'? Would you see if a pair of round-top CB750 carbs will fit into that if you have the parts ? Thanks 

I looked up part numbers, '79 and '80 have different part numbers for the airbox and airbox rubbers.

Oh,
Do you think the round-tops might fit the 1980' airbox rubber flanges ?

[onepieceatatime]

Oh,
Do you think the round-tops might fit the 1980' airbox rubber flanges ?

They will fit, but the rubbers are loose, so I don't know how well they will seal even with smaller clamps.


CB650 carbs


Round top carbs

[grcamna2]

Thanks for that 'Opaat',I appreciate you measuring.I'll figure out a way to add custom flange parts if it comes to that. 

[onepieceatatime]

No problem!!