'75 CB550K1 Gulf - Round...3, the fun stuff


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Picked it up yesterday. It's a sound runner, in good tune. The plan is to do a ground up build, completely strip everything and start from scratch. I haven't decided on color or well anything yet. Wish I had more to report at the moment, but I figured I'd just get my build thread started with this.

Re: '75 CB550

Wow! nice find! That is a lot better shape than I had figured. Has an exhaust, too...I want to see it in person :eek:
Re: '75 CB550

Yeah, the motor runs strong and the exhaust sounds great- just a little quiet for my taste. ;D I'm pretty happy with it.

Sad to say I won't be joining you on any more rides until spring though. I want to tear into the 550 and make sure everything's up to snuff before I ride it again. The 400 got dropped, and is out for the count, so from now on, nobody rides my bikes unless they are as good or better a rider than me! You'd think I would've learned the first time...
Re: '75 CB550 "Autumn"

Shit, nice starting point.

Sorry to hear about your 400. I really dug on that bike...especially the exhaust. You know what they say, "Fool me once, shame on you. Fool me twice...."

At least now you have the opportunity to one-up yourself.
Re: '75 CB550 "Autumn"

Thanks man. I will admit that I half-assed the 400, so if I give this one the attention it deserves, it should turn out pretty nice.
Re: '75 CB550 "Autumn"

I don't think I would say it was half-assed. Your standards have just gotten higher.

My first vintage bike was a '76 CB550. The only mod I made to it was clubman bars (and I paid a shop to do it), but to me it was "cafe". If I had it today, at the very least, I would have ditched the starter, put on some new exhaust, threw on some mini-billet signals, clubmans and a new fiberglass seat, and I'd have done the work myself.

I wouldn't rag on someone for "only" having clubman bars or anything, but I would no longer be satisfied with that as the only mod on my bike.
Re: '75 CB550 "Autumn"

You know, you're right. I would have saved myself a pretty penny if a year ago I knew what I know now, too. Live and learn!
Re: '75 CB550 "Autumn"

Been doing a bunch of reading on sohc4 today and with crazypj's help, I've convinced myself to do a cb750 piston swap/2.5 or 2.75mm overbore and a 650 cam swap. Should end up with around 590cc and waken the motor right up.
Re: '75 CB550 "Autumn"

Just found a sweet deal on a set of NOS cb750 pistons/rings/pins on ebay so that's done. .25mm oversize, so that'll give me 2.75mm oversize, around 595cc. *EDIT: 596cc to be exact** Will be needing to machine the pistons a little to fit the 550's smaller combustion chamber, but that should be straightforward. Having a hard time finding a cb650 cam...anyone have one? :)

Stability wise, I'm not happy with the front brake caliper sitting in front of the fork, so I swapped left and right forks so the caliper would be behind the fork. Good thing both lower forks have caliper mounting holes! The right (now left) mounts do need to be machined down a little to match the other side, but other than that, it looks to be a perfect fit. Curious why Honda didn't make them mirror images of each other...

I also got the frame stripped, and will be cutting it up shortly. I know, I have to break out the camera and stop being lazy. I'll get some pics up one of these days, I promise.

I do have one though. Check out the blob of shit that came out of the (very corroded) caliper when blew the piston out. I HAD to take a cell phone pic of that. It's amazing the brake even worked.
Re: '75 CB550 "Autumn"

I'm single, Tyler. I have all the time in the world. ;D But seriously, I only just got started. Finally finished my "shop" (cave), and tallied up all that I plan to do to the bike. Talk about sobering. I wonder how much the 400 will fetch on ebay. Might be just the cash boost I need to finish.
Re: '75 CB550 "Autumn"

I might sell it, Tyler. I move around too much to be hauling a couple bikes around. And my brother completely lost interest in it, he found Shinya Kimura's samurai choppers. So he wants to build something like that, but we'll see... i wouldn't sell it until this spring though.
Re: '75 CB550 "Autumn"

Hey fellas, finally got around to a little actual work. I wanted to give the rear a raised look so I started cutting/welding up the subframe. The long end tubes still need to be cut down and braced, and I might do a gusset or two in a couple places, but this is the basic shape.

You'll have to bear with me on the cell phone pic. Still need to charge the camera.

Re: '75 CB550 unnamed - subframe

Well I received the "OEM NOS" CB750 pistons in the mail today. The pistons, wrist pins, and circlips are fine, but the rings have some surface rust on them! :( Also, the oil ring is a one-piece, not a 3-piece. I thought OEM Honda rings were 3-piece. Anyone know?

Ah, gotta love ebay... So, I would think new rings are in order. Hopefully this guy won't be a douche and just refund it all - said everything was new/unopened/undamaged, but I wouldn't consider rusted rings undamaged.
Re: '75 CB550 unnamed - subframe

Okay, got the camera's battery charged finally. I'll get caught up on some pics of both Hondas this evening, but for now here's the rusty rings. I'm going to say they're shot so I'll have to get a new set of rings... Very nice that the guy didn't put that info in the listing. But I think I'll keep the pistons/pins as they are in great shape and they were so cheap. Oh well.


Re: '75 CB550 unnamed - subframe

Some better pics of the subframe. I'm not sure if I need or really want to do any gussets. What do you guys think?



Forks were a little rusty under the headlight ears. I couldn't find any rust-free cb550 tubes on ebay, so I got a set of cb650 forks and stole the tubes from them. They're about a half inch or so longer, so I'll just slide them through the trees a little.

Thanks for lookin.
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