Author Topic: 1978 CB550  (Read 2579 times)

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arrakis

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1978 CB550
« on: June 26, 2010, 08:34:06 PM »
Hi everyone, picked up this off craigslist for $300 about 2 weeks ago:

First bike, first post.  I just started poking around this forum, looks like a cool place so thought I'd start a thread.

The guy I got it from said he had it running "that morning" but the carbs starting spewing gas and he had to pull them.  Eh I thought, the bike was pretty complete (the carbs were in a box along with turnlamps), turned over, and the title was open.  Story was he had bought it from someone and was trying to sell it as is fast or get it solidly running and then sell it.
I'm working on a pretty tight budget here, at least until I figure out whether she's worth keeping.  My goal is to get her running, then drive around the block, then 5 blocks, register, then start riding and tweaking until winter when I'll decide whether I want to start some fabrication or modification on it.  One step at a time.

First thing I did was clean the carbs.  At some point they had been heavily painted/lacquered black.  Without being disassembled.  There was overspray all over inside the carb bodies, besides that pretty clean of old gas residue.  They had leaked because the float bowl gaskets were missing.  I split all four apart to soak them and then reassembled with o-rings I got from the local auto parts store and online at McMaster Carr.  I made the gaskets for the carb tops from gasket paper and replaced the little felt rings on the choke and throttle shafts with new acrylic felt and impregnated them with oil.  Anyone tried this before/what's the normal procedure with these?  I soaked a sample of the felt I used in gas overnight and it held up so I figured it was okay to use.  The one stock part I bought online, the float bowl gaskets, were too long so I shortened them with a razorblade and super glue.  I threw them on with the old gas line and a new inline filter, carb #1 overflowed, shot some carb spray in the main jet again and fourth kick she started up.

The choke cable is rusted in the housing so with the seat and airbox currently off I can carefully finger it into position and convince her to get started then back off once she's fired up   ;)  I'll have to rig something up soon for the choke, it's keeping the airbox off which I'm suspecting has something but probably not all to do with my idling.  Little bit of head scratching, thought I could rig a screwdriver/lever or something but it's f'ing tight in there.  My 1970 VW squareback used to make me curse the small hands of German engineers, this airbox is something else though.
At first it was idling pretty high up near 3000 but fell down to 2000 after 5 minutes or so.  Can't get it to fall with the idle speed screw on the throttle linkage on the carbs so figured it was time to maybe crack open the points cover and peek inside.
Was surprised to find no points:

I'll have to do some research here and find out how to time this.  Anyway, I thought I would also adjust the tappets because the nifty paintjob on the valve cover and tappet covers made it obvious the previous owner had also had his way in there as well.

Yup, that's black overspray on the rocker arm.  Decided it was worth removing to avoid the already peeling paint clogging something up.  I haven't pulled the filter yet to see how much of the paintjob has traveled around inside.

My other projects before riding her around the block include securing the seat, mounting tabs were ground off (sort of), I'm assuming in preparation for a cafe build:

A rear brake, it's a K, but has a supersport exhaust on it and the pedal doesn't fit anymore.  I guess the F's had a pivot point farther back on the frame?

Also maybe welding up a rear stand or something because the centerstand is missing.
And sourcing a chain.  Clutch and tranny seemed to behavior properly when she was running as I sneaked a peek at the front sprocket.

Offline Flying J

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Re: 1978 CB550
« Reply #1 on: June 27, 2010, 10:33:03 AM »
Welcome to the club. There is tons of info on here. My first suggestion is do a search on here for manuals. Get the manual it will really help. And almost any other info you need will pop up by doing a search. What is your plans for it?
300 is a good deal. When you did the carbs did you sync them? that will help it run a  lot better.

Offline Stev-o

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Re: 1978 CB550
« Reply #2 on: June 27, 2010, 02:45:35 PM »
Welcome to the club! You got a good deal but def some issues came with it. You're off to a good start!

These bikes run best with the airbox on, can be difficult to tune without it or if pods are installed.
Looks like your bike has been updated with electronis ignition, they came stock with points and condensors. Can't read the tag, is it a Dyna? I recently installed that on my 550F.

Yes, that exhaust mount looks wrong, click here:
http://www.hondaparts-direct.com/fiche_section_detail.asp?section=123302&category=MOTORCYCLES&make=HONDA&year=1978&fveh=2947

Good luck.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Flying J

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Re: 1978 CB550
« Reply #3 on: June 28, 2010, 10:41:08 AM »
Yes that is the wrong exhaust and if you decide to sell it i would be interested in the muffler if its not full of holes.

arrakis

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Re: 1978 CB550
« Reply #4 on: June 30, 2010, 06:47:25 PM »
Hey, thanks guys.  It's been so hot at work this week I've only had energy afterwards to just educate myself through the forum (and rehydrate) - I also picked up a sweet 550 Honda manual for free at Scribd, with the '77 addendum at the end - sometimes I f*ing love the internet.  The valve cover is cleaned up (pics to follow soon), but the phillips bolts were so boogered up I had to pull them with visegrips and I'm waiting on replacements as well as a drive chain.  This poor thing really had a nasty PO at some point - I forgot to mention earlier that when it was running I thought the tach was broken - when I looked closer I realized someone had the cables for the tach running to the front hub and the speedo running to the camshaft...

Yeah, it's a dyna S, which after reading the forums I've discovered seems to be generally considered a good thing.  The f exhaust on her is usable, but definitely nothing to get excited about.  The headers are dented up, and there's 2 fair sized holes in the muffler, one at the tip and the other near the coupling.

arrakis

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Re: 1978 CB550
« Reply #5 on: July 04, 2010, 07:27:19 PM »
I cleaned the paint off the valve cover, and the overspray off the rockers.  I'm not going for any polishing on the bike, just been trying to get the crappy paint job off the internals.



It's back on the bike and running again, but I'm still having problems with idling.  I'm trying to decide whether or not it's worth buying a carb sync gauge set.  I think I'll recheck the slides first tomorrow and start from there.

I attached an old 10 speed bicycle friction shifter to replace the rusted choke cable.  I drilled a hole in a coupler nut to pinch the derailleur cable at the carbs, and mounted the lever behind the left side cover.  I'll have to wait until it's rideable to see if the location works.  Works great now, was a nice quick fix.



Offline COOKIESandBEER

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Re: 1978 CB550
« Reply #6 on: July 06, 2010, 11:29:43 AM »
im digging the friction shifter mod, i guess thats just my bicycle nerd coming out. too bad you didn't have an old suntour superbe lever laying around now that would look clean ha.