Topic: CB550/650 First Bike Build

[seaninc]

Hey all, I think it's finally time to start putting thread together as my build is now starting in earnest. I do not even have a bike license yet (taking MSF class in 2 weeks) and this is my first bike build so please bear with my inexperience.

Last October my former coworker let me know that her neighbor was selling "some sort of Honda motorcycle" so I went to take a look thinking it was a CB750. When I got there I was presented with a very long-sitting '81 CB650 Custom. Saddle bags, sissy bar, crash bar and the whole cruiser look. I have no idea how long this bike sat, possibly even 15 years as it only had ~2000 miles on the odometer. I paid the $500 he was asking and way on my way.



*Please ignore the filter. I somehow lost the original

Got the bike home and it really just sat until this spring, minus some impromptu modeling by my better half. Pretty girl, very ugly bike.



Got the saddle bags and sissy bar off, finally. They're up for offer if anyone wants.



Then in May I happened upon a '74 CB550 rolling frame on Craigslist for $190, titled with engine and trans plus two newly balanced tires/wheels. Figured I might as well jump on the better looking frame so I picked it up in the East Village. Threw on an eBay tank recently. It's ugly and primered/bondoed but cheap and doesn't leak.



That's the current progress, I'll be here often as I have a ton of questions. My main wish is to retain the kickstart from the CB550 with the CB650 engine. Not exactly sure how to go about that, might just have to take them both apart and experiment. Another wish would be to keep the dual discs front end from the CB650 but I don't know if the shocks are too tall for the 550. Any input is greatly appreciated!

[rb550four]

Okaay here's the deal . There won't be a kickstart on the 650 engine. Q: Are both machines titled/ transferred to you? If yes I would do 2 builds. if the 650 is untitled that's a different story.

The 650 engine will mop the floor with the 550-, the 650 is a straight on drop in in the 500 or 550 frame.

The entire front end from trees , forks,wheels, discs and all will fit in the 500/550 frame. it's a no BS swap.

The 650 swing arm is about an inch and a half longer than your 550's, The 650 will out handle the 550 stock, if you are switching to the longer 650 front end you should consider swapping out the swing arm,-you will have to drill out the swing arm bolt hole in the 550 frame to accept the 650's larger swing arm bolt. The shocks from the 650 will also improve the ride and with the swing arm swap will handle like the 650.
hope you like comstock wheels over the 550 spoked rims, they are not interchangable so the can't go back on the 550 if you make these changes. You can get wider tires with the comstocks...I didn't like them at first, but they grew on me quickly.

The 550 wiring harness will have to be altered if swapping the 650 engine in the 550, it is way easier to swap the 650 harness into the 550 frame you will have to do some mounting alterations such as 650 battery box into the 550 frame-not too tough, the 650 air cleaner will be a tight fit but it will work. I understand that the 650 runs like crap with pods so best to stick with stock 650 set up.

The 550 and 650 seats or rear fender are not interchangeable , that fact alone will retain the classic look of the 550 especially with the stock 550 tank. Most guys wouldn't know the difference out on the street. But we'll all know the difference here.

The 650 tank can be used on the 550 frame with a simple alteration (drill new rear mount hole on the frame) but it looks like $hit with the 550 seat.

You may have to find a different brake pedal as they are mounted in close but different places especially if you are using the stock 650 pipes(clearance issue) I forgot which on I used when I did this, but there is a stock 550 solution (ebay if you have to) but you never know if another member may have an extra one.

Yeah I am interested in your project and would like to see what you do. Good luck and keep the pics coming.                                                                        RB

[rb550four]

Almost forgot, don't throw away your unused parts, lots of guys here might be looking for them, okay , maybe I'm looking for some parts.... either way , give us first shot at them please.

[goldarrow]

I would do two builds. One for you and one for your better half.   Looks like she's interested in riding also.   

[MiGhost]

Gotta jump on the two build wagon here. Especially if you have titles for both bikes.
1. CB650C: Get it running, cleaned up, and safe (it has been sitting for some time) for you, and your girl to enjoy a bit of two up running on the town. This will be a great bike to get your feet wet while learning how to ride. A sharp, low mileage classic gets plenty of attention. Even if it is the forgotten stepchild.
2. CB550: These make great little cafe/chopper bikes. The possibilities are nearly limitless. If you use the 650 top end (crank, pistons, jugs, head) on the 550 bottom end (cases, trans). You can make a serious motor while still retaining the kicker. paulages has a write-up on the 650/550 stroker motors.

The basic questions that you need to answer are.
What do YOU want out of the bikes?
Do you want to be wrenching, or riding?

Do not be concerned with how long a project takes to build. They usually go through changes as they progress along, and you learn of a mod that you just have to do on yours. You have two great bikes to start with. Get wrenching, learning, and rolling

[seaninc]

Gotta jump on the two build wagon here. Especially if you have titles for both bikes.

The basic questions that you need to answer are.
What do YOU want out of the bikes?
Do you want to be wrenching, or riding?

Thanks for the advice, Ghost. Unfortunately I really only have the time and money to build 1 bike right now. I'm an older engineering student (second shot at college) still living at home so my parents would flip. Both bikes are titled and a friend is interested in building a bobber with the 650 frame. I'm picking up another 650 parts bike tomorrow so he'll have an engine.

The goal of this bike is to commute to school and work most days. Not really a cafe bike, but stripped down with a flat seat for two and superbike bars. My commute is 40 miles each way.

hope you like comstock wheels over the 550 spoked rims, they are not interchangable so the can't go back on the 550 if you make these changes. You can get wider tires with the comstocks...I didn't like them at first, but they grew on me quickly.

The 550 wiring harness will have to be altered if swapping the 650 engine in the 550, it is way easier to swap the 650 harness into the 550 frame you will have to do some mounting alterations such as 650 battery box into the 550 frame-not too tough, the 650 air cleaner will be a tight fit but it will work. I understand that the 650 runs like crap with pods so best to stick with stock 650 set up.

I plan on swapping over the entire harness from a 650 parts bike I'm picking up tomorrow. I've heard the 550 charging system is a pain. I really do want spoked wheels with dual discs but could live with comstars if I could find a larger rear wheel. Really hating the 16" rear on this bike.

I would do two builds. One for you and one for your better half.   Looks like she's interested in riding also.

Unfortunately she's living in London right now and likes the look of bikes rather than me riding one. She's moving over within a year so we'll see if that changes.

[seaninc]

Got a free parts bike along with some rebuilt VB44s set up for dual K&N filters. Parts bike came with Koni shocks and nicer pipes so I made out like a bandit. Oh and it's titled if anyone needs a titled frame. Pics tomorrow if it doesn't pour.

Sent from my super cool phone using my thumbs

[seaninc]

Started taking everything off the CB550 roller tonight. Taking it to a friend of a friend for a cafe loop quote tomorrow morning. I picked up another 650 parts bike on Wednesday but damn, it's not pretty. It was free with the carbs I bought, though, and has a set of Koni shocks and better pipes that I'll use on my project. Based on advice above, I'm going with the 650 front and and swingarm. Once welded and stripped the frame is getting media blasted and powdercoated.

[seaninc]

Dropped the rolling frame off at Miro Ovcharik's shop. He's a friend of a friend and also a Formula Drift driver (in the S13).



In other exciting news, I'm defecting to hondatwins.net...NOT. But I did pick up a running and titled SL350 for $300 today, woo! So glad to have something as a daily rider. I'm taking my safe rider course next weekend so looking forward to commuting on that new toy. Pictures tomorrow for sure.

[MiGhost]

I gotta say. That parts bike looks more fitting for your buddies bobber project, and its already missing most of what he will not need.

How much of that complete 650 would you be willing to deal on?

[seaninc]

I gotta say. That parts bike looks more fitting for your buddies bobber project, and its already missing most of what he will not need.

He's getting the frame since the title's in my name. I'm keeping the engine, front end and swingarm for the 550. Sorry.

[seaninc]

Here's my new toy! 1972 SL350. Couldn't pass this up since it's running and titled. Needs a tail light and I put in a new battery. Not bad for riding to work

[Tews19]

Subscribed!

[seaninc]

Welcome aboard, Tews. Hopefully I can keep the progress going.

[Tews19]

Sweet info RB! I've read where some say the 650 swap into a 550 isn't worth..... how much more hosepower is gained? If the swap is done, will it still as nimble as a 550?

You have me questioning myself now on my build...should I just do the 650 cam swap or be somewhat different and do the 650 enginw swap?? What if one uses a modern 2006 gsxr front end, will still be an effective upgrade?

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[Scott S]

 Take a look at my build thread. The 650 swap starts on page 4.

http://forums.sohc4.net/index.php?topic=67907.0

 The 650 is much, much more powerful than the 550. You may have to deal with petcock issues....it may be too close to the carbs. I got lucky, but you have a different tank. I've seen another person do the swap using the same tank I have but earlier carbs and he had issues. It's all in the combo.

 Speaking of carbs, make sure that whatever engine you use, you have the correct carbs for it. The '79-80 engines used mechanical carbs; the '81-82 engines used CV carbs. They will not interchange without swapping the head.

[Tews19]

Thanks Scott! I just Pm'd you too about this... Are the CV carbs the way to go??? Oh I am dying now for more insight.. Got to do some more research but I am think this may be fun.... I am not to worried about the petcock issues. More of the reliability issues for the 650 to the 550 engine.. I am familiar with the 550s and I am think what the hell. Let's jump in head first....

Sorry for the hijack...

[seaninc]

No worries on the hijack! It's good info for me too. The reason I'm doing the 650 swap is I have a complete 650 but don't like the cruiser style. The 550 frame gives me the look I want. Will I have petcock problems if I use the CV carbs and a stock 550k tank?

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[Tews19]

Sean I just read Scott's build thread.. He fixed the petcock clearance issue.... I am officially looking for a 650 engine!

[Scott S]

 To clarify: Another member used the same (early style) tank I have. He did NOT have the CV carbs. He had petcock clearance issues.
 The only thing I can say for certain is that the style tank I have and CV carbs work fine. Sean, you have the later '77-78 style tank. I simply don't know what to expect with the petcock....you may be just fine.

 What year is the second CB650 engine you picked up? I see you have CV carbs; the second engine must be an '81-82 in order to use the carbs you have.

[seaninc]

What year is the second CB650 engine you picked up? I see you have CV carbs; the second engine must be an '81-82 in order to use the carbs you have.

Whoops, so I have an F tank? Both my 650 engines are '81s with the VB44A carbs.

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[Scott S]

 Well, it's not necessarily and "F" tank, just a later model tank with the flip up filler cap door, right? I'm not sure if the petcock bung is in the same position as the earlier style tanks. Guess you'll have to test fit it to be sure.

[MiGhost]

To clarify: Another member used the same (early style) tank I have. He did NOT have the CV carbs. He had petcock clearance issues.

What carbs did he use?

The 79-80 650 used the same base PD mechanical slide carbs as the 77-78 550. There should have been no issues with the petcock clearance unless something other than PD carbs were used. The CV carbs are wider due to the round slide caps. This may cause the clearance issue with the tanks.

[Scott S]

 Well, he DID use CR29's....

http://forums.sohc4.net/index.php?topic=114345.0

 However, even though the '79-80 used PD-like carbs, the 650 doesn't have the manifolds that move the carbs back. Who knows? The PD style carbs may clear just fine. I only know for sure about the CV carbs.

[free85]

Is there an option (or a desire) to do the 550 bottom end with the large bore 650 top end?

http://forums.sohc4.net/index.php?topic=40414.0

   I have a '78 CB550K, and the above thread makes me smile when I think about it.

[seaninc]

Is there an option (or a desire) to do the 550 bottom end with the large bore 650 top end?

Just no real desire to tear down two engines. I don't really trust myself building one.

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[seaninc]

Got the rear loop from harisuluv welded on today!



One step closer. Next order of business is to get some powdercoating quotes for the frame and spoked wheels. Any reason I should go with paint instead?

[free85]

Is there an option (or a desire) to do the 550 bottom end with the large bore 650 top end?

Just no real desire to tear down two engines. I don't really trust myself building one.

Can't say I blame you here. Good luck. Rear hoop looks good.

[seaninc]

Been too busy having fun on my SL350, but that's child's play Time to work on the "big bike".

Tore into the CB650 donor today and I'm running into some issues. I really, really want to run the dual disc front end but with my spoked wheels. Any idea if there's a hub I can lace to my CB650 standard rims AND will give me the proper rotor spacing for the dual disc front? I'm thinking a CB750 hub will allow me to bolt up 2 rotors but can't confirm the spacing.

[inferno]

I've run into the same problem. I'm stuck with the cb650c mags until i can find an entire front off a cb650 spoked. apparently the only way from what i am told.

[seaninc]

Wow, it's really been a while. Been busy with work and school but finally got back to work on my project bike. Sold my SL350 last week so I'll have some cash to dump into this turd.



Started by enlarging the swingarm bolt holes on my CB550 frame so I can fit my CB650 swingarm and bolt. A new drill and 5/8" metal cutting bit took care of that and left me with the perfect tolerance.



So I'm currently trying to get the bike into rolling shape. 650 swingarm, Koni shocks and wheel are on for now. I have a set of spoked wheels ready to go after I pick up a Gixxer front end and a narrow glide hub.