Fixing an old Honda Motorcycle
May 2, 2006 9:50 AM   Subscribe

How interchangable are parts on Honda CB motorcycles from 1974 - 1985?

I have a 1976 CB 550 that i've put a lot of work into. I've totally rebuilt the wiring harness, added an electrical ignition system, replaced the forks and fuel tank -- basically put a lot of money into it already.

Now my head gasket is leaking pretty badly and i am about to move cross-country. My mechanic tells me that with the leak, the bike is unlikely to make it to the east coast, but their estimated cost of repair (rebuilding the whole engine) is approx $1200-1500, which is too rich for my blood.

I have found clean engines for cb550s from the mid-80s, as well as one from a 1978 cb 650. How difficult would it be to fit these engines to my bike?

Second, as a reasonably mechanically intelligent person with little experience working with engines -- how realistic is it to set out to rebuild the engine myself, and what resources should i start with for my research?

posted by milkman to Sports, Hobbies, & Recreation (8 answers total)
I rebuilt an xs650 engine over the winter, having zero experience with engine work, but consider myself fairly "handy."

First of all, it's hard to say what all you'll have to do once you get inside. Anybody who has worked on motorcycles will suggest the following: don't crack the case unless you absolutely have to. I've guessing you need a top end job only (1500 sound pretty high, IMO.)

Your first resource would be to get 2 manuals. I've found both chilton and haynes to be good in tandem, but without both, you may miss some subtleties.

Be sure you have plenty of room, take your time, document everything you take apart. A top end engine job at worst, would be to replace the pistons / rings, rebore the jugs, replace the valves (port and polish), replace the cam-chain, gaskets, and that's about it.

This is standard fare on a top end rebuild, but you might get away with spending / doing less. Without indepth research of the later year hondas here's my diagnosis / suggestions.

Bike built from the early eighties on are tuned to run lean, in lieu of emissions and fuel efficiency (like bikes aren't clean enough comparatively.) What that means to you, you might have to get different carbs, rejet the current carbs, as well as modify your exhaust if jetting doesn't permit the optimal fuel mixture. Different air filters, etc.

One last thing to consider is part availability (shouldn't be a problem they made a ton of 'em)

Good luck, drop me a line if you have any further questions I might be able to help with.
posted by AllesKlar at 10:07 AM on May 2, 2006

To answer your first question, my guess is that there might be a difference in mounting and frame geometry between the different years. You'd have a better chance if it was the same engine, within a couple of years of yours. I notice that the Clymer manual covers the CB550 from 1974-1978, so an engine from those years might fit. You might want to ask around the Honda bike forum.

To answer your second question, if you're handy enough to do an engine swap, you'll probably be okay rebuilding your engine, though it will take longer and parts for older bikes can be costly.

Anyway, good luck with whatever you decide to do -- that's a great bike. I had a '75 CB550F with the 4 into 1 pipes that I bought new (damn, I'm old) and sold 10 years ago.
posted by SteveInMaine at 10:29 AM on May 2, 2006

Back in the late 70's I, too, used to own that exact bike - well the four pipe 'K' version anyway. Lovely bike. But I digress.

Don't ask us. As SiM notes, the key issue is the engine mounts. I'd guess the CB650, which, IIRC, was essentially the same engine, would have the same mountings, but my guess is worthless to you. Ask people who know or who have access to the right reference sources, i.e. the mechanics at your Honda dealership with the best reputation for repair competence.
posted by mojohand at 10:38 AM on May 2, 2006

Oh, and while doing the swap or rebuild yourself is quite practical, and a great opportunity for building competence and self-confidence, I would never, never, ever start projects like that, where I would be constantly on the learning curve, facing a hard deadline. Maybe it would all work out, but that's not how I'd bet.
posted by mojohand at 10:50 AM on May 2, 2006

I see you are in San Francisco - Is your mechanic Charlie at Charlie's place on 17th? If not - you might want to call him and see what he would charge to do the work. He would also likely know about engine swaps in older Hondas. It's all he does. I had him do some work on my 400/4 - very reasonable prices and super friendly.
posted by Wolfie at 11:04 AM on May 2, 2006

Response by poster: Yeah, actually i deal exclusively with Charlie's place. That's where my estimate came from.

Unfortunately, I am looking at a hard deadline. I might have to let this one go.
posted by milkman at 11:05 AM on May 2, 2006

One last idea - why not ship the bike to where you are going? My husband has used the same company a couple times to ship bikes from here to the east coast - and it was less than a few hundred dollars. I've got a call into him to get their name. The engine rebuild could then be something you did at your leisure rather than with a deadline looming.
I'll assume you know about these guys in case you do end keeping the bike as a project for the other coast.
I'll post again as soon as I get the name of the bike movers.
posted by Wolfie at 11:34 AM on May 2, 2006

Hmm - just talked to the husband. apparently I'm remembering "cheap" relatively. He said it was about 500 bucks and you had to crate the bike yourself and get it to SFO. He says the company was called Arrow Freight in South San Francisco - but I can't find them online. Sorry my suggestion may be a bust. 500 bucks is well on your way to a new CB 550 once you get to your destination.
posted by Wolfie at 1:26 PM on May 2, 2006

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