Topic: 1978 Honda CB550K: Project *Education* Now W/ Video

[OneWheelDrive]

Whew...it's been about six months since I started creepin' through this site and the seemingly unlimited volumes of knowledge hosted here.  As I started describing in my "550 Basket Case: Purchased for Cheap" thread, I finally found the right deal, for the right bike: a currently titled 1978 CB550K in seemingly pretty decent shape for a final negotiated price of $225.  

The bike appeared complete, with most of the miscellaneous parts in milk crates including velcroed DIY seat (original seatpan is rusty swiss cheese), but the top end of the motor was removed.  The PO stated that the cam chain broke while at speed, and he never was able to commit the time to the repair.  



I decided the easiest and cheapest way to get this sucker running was to find a donor motor, and within a day of looking, I had found a generous parts hoarder nice enough to offer me a motor for $100, I'm yet to see if the Dyna ignition is included in that price.  I'm gonna grab it on Sunday when I have time to make the drive.

After a week of peeking into my garage, I've finally had time to start digging into the crates of parts to share photos with the class.  

Plan of attack is definitely going to be remove the 90 lb paperweight from the frame, get the runner in there, overhaul, bench sync, and tune the best set of carbs, assemble the accoutrement, reconnect the jumbled harness to a new battery, cross my fingers and push the button!

With the bricked motor out of the bike, I'm gonna tear the thing apart piece by piece, not necessarily with the intention of rebuilding it, but more to absorb the mechanics and to familiarize myself with all of the parts.

After I've got a good runner, and I spend some time falling in love with riding her, I'm going to do a full frame off resto to very close to stock with some functional upgrades (original aren't I?).  Gonna clean the years off of every part, likely with a cheap-o soda blasting cabinet.

Then frame and miscellaneous part powdercoating and/or home polishing, including wheels, exhaust and engine exterior.  Definitely a stainless allen bolt set upon reassembly.  Eventually a professional paintjob on the tank and sidepanels.  Then I'm thinking modern suspension, tires and brakes.  Perhaps a simple front end swap but a fork rebuild at the least w/ tapered bearings.  Also a mildly cafe inspired custom (2 up) seat, comfortable bars, and K&N drop in filter (don't want to get frustrated by pod tuning).

My goal is not to produce a BOTM, but to learn, enjoy the process, and make something that is my own that I'm happy with.

Here are some pics finally!

Baby Vespa 150 in the background




Top end removed


Crusty pistons, some contact from valves


Gauges are in OK shape, back mount for the dummy lights is snapped off


THE CULPRIT


Busted Cam tensioner?


Bolt baggies, hmm, "misc"?


Pretty excited to rip into the carbs







Blah





Hmm, where's the fuse panel?


A bit crusty




Couple of decent looking side panels.  No 550Four emblems though


More misc.?


OOOH, I likey





More wiring nastiness



I can't wait for everyone's help and support as I finally join the Honda brotherhood!

[chronic_rider_550]

Lookin great man! Sweet bike. I'll be following this thread to see how she turns out.

[harisuluv]

Cool beans, man.  I'm in the same boat as you, same exact year, I got a k, though.  I'm getting ready to start mine soon and ride *hopefully* so I got a lot of parts leftover, if you need anything, just ask me.  Also, if I were to guess, I would say that "miscellaneous" bolt was the upper right rear engine hangar bolt that also is the lower bolt for your battery box.  Good luck.

[Greggo]

Subscribed!  Nice lookin exhaust, you could probably recoup your purchase price with that alone.

[Stev-o]

You do know that exhaust is for an "F" model, right?

Is the sidestand seem more forward than "normal"? If no, you may have an F model. Post a pic if you are not sure.

Those are aftermarket side covers. If you are interested in another pair, Frankenstuff is now making them [check the for sale threads].

Good Luck!

[Greggo]

You do know that exhaust is for an "F" model, right?

Is the sandstand seem more forward than "normal"? If no, you may have an F model. Post a pic if you are not sure.

His VIN reads CB550K.

[ksmith0034]

You have obviously done your homework here and have a plan in mind.  You're already one BIG step ahead of most!  Keep us posted.

Nice shoes!

[OneWheelDrive]

Thanks for the encouragement guys.  The exhaust is still slightly a mystery to me.  I know it's an F exhaust, and the VIN clearly shows that it's a K, but I think I've seen '78s with 4 into 1s.  My understanding was that the F exhaust interferes w/ the center stand, and leaves the motor differently, but as I picked the bike up w/ the exhaust removed, I'm not sure if there's an issue (yet).

Got some work in this morning, wrestled with a stuck engine hanger bolt, but got the motor out on my own.  Certainly not easy, but not so bad w/ the top end removed already.  I do have black cooling fin marks on both forearms from bear hugging the thing though.



Check out the nasty damage from the cam chain running untensioned.



Also had a pretty nice gasoline spill when the petcock swung open when I set it down on the bench, "Honey!? What's the smell!?",  .  Can't believe I didn't sleep on the couch when the wifey found out I bought it home.  Plugged the fuel line with a bolt for now.

Oh, and the shoes are custom made Vans that I had made for my wedding last year.  Me and all the groomsmen wore them.

Should have the new motor in my possession by tomorrow some time.  Hopefully I can snag a few extra parts from the guy as well. 

[harisuluv]

wow that is some serious cam damage.  looks like the cam tensioner gave out and then the rubbing on the cases caused it to break, bummer!

[OneWheelDrive]

Motor with Dyna ignition in the trunk of my car for $130!! 

We did do a compression test, and cylinder 2 was pretty weak, just under a 100  .  1 was 155, 3 was 148, 4 was 155.  Guess I'll be looking at a top end rebuild after all.  I'm hoping it's just crud in the valves.  All I know is that it's gonna be much better looking than what I yanked out of the current bike.

It also came with 750 carbs, pretty filthy and crusty, but can't hurt to have a spare set.  Rebuild and ebay perhaps.  I've got some parts en route that should get me pretty close to everything I need for the runner!

[Greggo]

Nice!  Are those the 750 carbs on it?  You could almost have yourself a free engine if you hawk those..

[OneWheelDrive]

Any reason not to use the 750 carbs instead of the stock 550 set?

[fantino]

I'm sure they would work, but they're not really designed for the characteristics of a 550... if the valves\ports or the displacement of the engine haven't been modified, then I think 750 carbs just have a lot of throat for a stock 550, which I *believe* results in shifting the powerband up a fair bit higher. I don't know much about carbs or 750s, but I do know that unless they've really been set up correctly, they'd probably be a nightmare to try and jet for good streetable performance. Hopefully someone who knows more about this will chime in though :-p

Very cool project, and great deal on the new motor\ignition. Can't wait to see what you do with the bike :-)

[DavePhipps]

just throw a 650 head, 650cam, and modified 78 cb750 pistons in it. 592cc displacement and free flowing head,10:1 compression, then those carbs will be fine.

[OneWheelDrive]

The 750 carbs and the Dyna ign. make me wonder what the internals look like in there.  It may be a downgrade to put the 550 carbs back on it if the 750's have been tuned to match the motor already.  I also don't know what filter set up was on there.  I know the motor was on a sand rail, so it likely was pods.  Either way I have a feeling I'm gonna have a heck of a time tuning whatever I chose (air filter/carb combo) to my 4 into 1 exhaust.

It also has a full stainless allen screw set so it's obviously been rebuilt.  I'm not going to open the top end until after I get it running, but maybe there a nice big-bore surprise and 650 cam already in there! The guy I bought it from bought it from his father-in-law and never started it so it's a $130 mystery motor.

[Stev-o]

I would not assume it's been rebuilt just 'cause the the screws were replaced.

[OneWheelDrive]

I would not assume it's been rebuilt just 'cause the the screws were replaced.

Fair enough, maybe I should have said "probably rebuilt" instead of "obviously rebuilt". 

The mystery of the 750 carb combo kinda scares me.  It would be hard to tune without knowing what's in there right?  Do I need a 750 stock airbox or can I run the 550 box I have?  Or should I just take the jump to pods considering I already have a 4 into 1?  I know the more things you change at once, you end up searching endlessly for the white rabbit  .  Maybe I'll start w/ the stock carbs, stock airbox, and get it runnin' before I dig too deep of a hole.

[fastbroshi]

That is a 500 motor btw, not a 550

[OneWheelDrive]

Wow Broshi, very astute.  I hadn't wiped off the VIN, but sure enough, it's a 500.  Looks like I now have no matching components at all....  Should I try to sell the 750 carbs, Dyna ignition, and 500 motor and just find a 550? Or could I make this combo work?  Looks like this is turning into project "mismatched"

[Stev-o]

There's your catchy name - "project mismatched"!

[Greggo]

That 500 motor doesn't look half bad...I say keep it.  Like YOU said - It can't hurt to have a spare  

[OneWheelDrive]

Project Mismatched doesn't quite have the ring I would like it to, although it does seem to be a collection of good condition parts from a number of different bikes.  When she's done, she'll be beautiful in her own way.  I'm determined to make the best of what I have, and barring some tuning nightmare, get her running.  

It took me four days, about 45 minutes at a time, but I was able to complete the carb rebuild last night.







Zipties work well for retaining the order of washers/springs etc.


Nothing groundbreaking, but definitely an improvement and I know they're clean as a whistle and complete inside.






After getting the carbs back together, in a caffeine-fueled frenzy (my other hobby is restoring old espresso machines :-D), I decided to crack into the motor to see what I really had going in there.  

Ratchet straps to get to the oil pan worked quite well.


Oil pan and screen looked very clean inside, no signs of sand or metal parts.





Looks like maybe some rust on the kick starter gear?


Is this an aftermarket oil cooler adapter?  The inlet/outlet barbs were just plugged w/ rubber caps.  Wouldn't this be under pressure?


Oil pressure guage, cool addition.  Hopefully the seal is good and it stays out of the way of the shifter.


Bah, of course, the last screw I try to take out is entirely rounded.


No biggie.


Very clean valve train.




A peek inside.




Hopefully she'll will cooperate as I continue to move through the process.  All in all I am very pleased with the condition of the top end, but haven't yet inspected the cylinders or piston walls.  I've heard there's an old timer that does valve jobs and cylinder checking/honing for cheap around me, so I think I'm gonna do it right and send it out for this work.  

[Stev-o]

You're making good progress and seem to know your way around a motor. Have you wrenched other bikes?

[OneWheelDrive]

I did help a friend rebuild his CL175, but no internal motor work.  I was raised on Legos, so I'm good at following directions :-D.  It's all very intuitive to me, my biggest challenge is going to be getting the parts I need that match my bike for the budget I've set aside for the build.  I'm only a week in and I'm already pushing it!  The good news is that I'm happy to produce a "garage bike" (although many of the bikes you guys build in your garages rival shop builds!) that fits my personality and that I know I did with my own hands.  

[OneWheelDrive]

So I've gotten the entire motor clean and top end removed.  Waiting for head and cylinder base gaskets to arrive.  I did order a cheap top end rebuild kit off ebay that included both gaskets, but when I button this motor up, I want it to be the last time for a long while.  For this reason I sourced OEM gaskets from partsbandit.com, and they should be here next week.







In the meantime I received the new fork seals and tackled that job.  I didn't photodocument, as i was pretty into the process.  I did run into a few snags/bad news however.  I had a bear of a time getting one of the forks to drop, as it was rusted to the lower triple pretty badly.  Eventually it gave way with some raps with a rubber mallet. 

The oil that came out of there was naaaasty, dark rusty brown and very watery. 

The next issue came in removing the allen bolts from the bottom of the fork, but again, with some ingenuity (read: blowtorch), i was able to get them to break free. 

After I had the forks all disassembled, I wanted to check to see if the fork tubes were straight.  Using a straight edge, it looks like both forks are about 3 mm bent.  Hardly noticeable, but I hope it doesn't affect the ride. 

Getting the old seals out of there was a PITA as well, but ended up using a large crescent wrench to lever them out.  They were terrible looking, crusty, rusty, cracked.  I'm definitely glad I bought new ones.  New seals went in no problem.  Reassembled, filled with fresh oil, and replaced them on the bike.  BTW, HOW CRUCIAL IS LOCKTITE ON THAT LOWER BOLT?

A bit more bad news, however.  It looks like whatever bent the forks, also put the wheel slightly out of round.  There's a pretty noticeable wobble on the rim and tire.  Again, hopefully it doesn't affect the ride once I get it running.  I guess I'll have to plan to replace the set when I move on to the "make it look nice" phase of the project.

I'm looking forward to getting the gaskets and getting the motor back together.  I still haven't had a chance to buy feeler gauges to measure ring gaps or have the cylinders measure for roundnesss.  Tomorrow probably.  I'm hoping that the rings and cylinders are good and I can avoid some expense there.

I have a feeling the next major challenge is going to be electrical.  The harness looks pretty complete, but figuring it all out is gonna be another learning process.  Not promising, however, that the PO said he had been having "electrical problems".  Not in charging or ignition, but lighting, switches and indicators, all of which was removed from the bike when I took the project over.  I do have a multimeter and a willingness to learn, so I'll just have some reading to do.

Oh, other good news.  I finally had a chance to get my M1 permit!  Only missed one question.  Anyone know the penalty for evading a police officer??  A: No less than 1 year in county jail?  B: No less than 6 years in state prison?  C: No less than a $10,000 fine?  Time to get this bike running so I can take that test!