Topic: 79 cb650 into a 77 550 frame with a bunch of other stuff

[thatoreoguy]

Hey all so I have built a few bikes before and previously raceed 600 class crotch rockets.

My first venture into the cb world. Plan is going for the look of the green and silver wrench monkees cb750

I bought a cafe'd cb650 without papers runs and drives
I also bought a 77 550 k frame and engine with papers  *( i'll be selling the engine and K series carbs if anyone is interested.

The idea is to fit the 650 engine and errythang into the 550 frame. On top of that with a few tasteful mods to make it a fun DD

Planned Mods:
- New exhaust... any recommendations?
 - CR or gpz600 carb swap  ( opinions? the ninja carbs are cheaper and with "Soos" write up I have an excellent starting platform) but the cr carbs are drop in fantstico
- CR750 tank ( where to buy one thats not fiberglass?
- Electrical is good but wouldn't mind an updated system
- Maybe single sided swingarm from something
- Front fork moderno swap while trying to keep wire wheels !

[SOHC4 Cafe Racer Fan]

Planned Mods:
- New exhaust... any recommendations?

Oreo,
There are several members who have or are in the process of swapping a 650 motor into a 550 frame.  DaveBeabier and I are in the process.  I believe rb550four has also done it before, as well as others.  In addition, there are other members like Paulages who have swapped in the top end of the 650 onto the bottom end of the 550, but this requires some adaptation work.

I am not aware of a turn-key aftermarket exhaust for the 650.  I was planning to start with the headers off my 650 and modify them at the collectors, or use them as a model to have a new header made.

- CR or gpz600 carb swap  ( opinions? the ninja carbs are cheaper and with "Soos" write up I have an excellent starting platform) but the cr carbs are drop in fantstico

I was not aware of the GPZ swap.  If you have a 79-80 engine, you can use stock 750 carbs.  I am going to start with the stock CV carbs (since my engine is from a 1982 model 650) and move up later to CRs.

Planned Mods:
- CR750 tank ( where to buy one thats not fiberglass?

Mead Speed, CMR Racing each make aluminum CR tanks, but they are outfitted for 750s and not 550 frames.  CMR can do it easy because it has access to both frames.

- Electrical is good but wouldn't mind an updated system

My electrical is gone. I will likely go with a Motogadget M-Unit set-up.

- Maybe single sided swingarm from something

Interesting.  More weight but cool.  Devin at Cognitomoto adapted a Monster swingarm to a CB350 build. 

- Front fork moderno swap while trying to keep wire wheels !

Devin at Cognitomoto offers turnkey hubs that will work with GSXR and CBR fronts to lace up to spokes. Check out which years are compatible to his set ups.

[thatoreoguy]

Planned Mods:
- New exhaust... any recommendations?

Oreo,
There are several members who have or are in the process of swapping a 650 motor into a 550 frame.  DaveBeaubier and I are in the process.  I believe rb has also done it before, as well as others.  In addition, there are other members like Paulages who have swapped in the top end of the 650 onto the bottom end of the 550, but this requires some adaptation work.

I am not aware of a turn-key aftermarket exhaust for the 650.  I was planning to start with the headers off my 650 and modify them at the collectors, or use them as a model to have a new header made.

Any tips and tricks? It looks fairly straight forward and having the frame together I should be able to unbolt and bolt back up pretty easy.

I only am think a diff swing arm because i heard the 550 is a little shorter. So 'id like to make it a little longer for the similar style and ride stability.

The first incarnation will be a clean swap over.

Exhaust. Yeah I have a few friends that build custom exhausts for cars so i will be getting their services. Maybe I can do a small batch run.

Thanks for the links and any other info feel free to hit me up. I still have to check out the 79 to see if its a later model cv carb setup or the older mechanical style.

[rb550four]

You can use the 650 swing arm but you'll have to drill out the mount to fit the larger 650 bolt. This solves the chain issue that goes with the swap... the 650 has a bigger chain. if you have the standard, not the custom  , you can use the 650 wire rim then too. If you have the custom , you'll be looking at comstock wheels, ugly , but will bolt right in correctly. Can upgrade to the 650 shocks...better than the ones on the 550. No one has been able to put dual disc set up on the front end of the standard 650 wire wheels. I forgoot which year , but 1 year there was a custom model that had dual disc on a comstock wheel...what a waste.
  The entire upgraded 650 front end will fit on the 550 with no adaptors, just bolt it in at the neck.
I usually use the complete 650 wiring harness, and will gladly switch to a Pamco electronic ignition on the 550 wiring harness. One, aftermarket 550 wiring harnesses are for sale and they are inexpensive , or you can use your working 550 harness.
Two , no cdi boxes to buy, just one of them cost as much as a repro 550 harness , and you need 2.
Decent 650 electrical stuff is hard to get and has little offerings in aftermarket...except for Rick's or you go hunting for other off model parts. If interested in this , member Pamco Pete is the man to PM , he's interested to know what to expect so he can do a production run.
  Mac makes a header for a 650, got one last year. Haven't found any other manufactures for pipes.
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050890.m570.l1311.R7.TR10.TRC0.A0.H0.Xhonda+cb650.TRS0&_nkw=honda+cb650+exhaust&_sacat=6000

                                                                                                              RB

 

[rb550four]

  Oh and by the way, and anyone else who is doing the transplant, the F model works better than the K frame, you will find that you will be sourcing an F model brake pedal, the K pedal interfeers with the exhaust. If you want to stick with stock Honda parts. Then there 's the rearset option.

[thatoreoguy]

Thanks for the Info I'll prob go with a tazzori rear set like set up or something custom. I will prob upgrade to modern forks off GSXR or R1 so the front hweel will be relaced with a dirt bike rim or something haven't gotten that far yet