Topic: 1975 CB550 K1 restoration - DONE!!!

[reddyvv]

Hi Everyone,

I just joined the board a few days ago and have been getting some fantastic information from reading all the threads!! I recently purchased for the grand sum of $300 a '75 CB550. My plan is to restore it to "good" running condition i.e. not a show bike but not a rust bucket either. At first inspection:

THE GOOD
8,300 miles - still has original rubber
Unmolested, never had a wrench put on it.
Chrome should shine up good, just some slight surface rust on the undersides and seams


THE BAD
From the registration I got with the bike it hasn't been started since ~1980
Engine is seized up solid from sitting
#1 and #4 exhausts are rotted at the header/muffler seams - previously hack welded.
#4 header is 3/4 blocked with a serious ding in it
A couple of fins broken off on #4  - must be related to the header incident.
Original rubber is turned into hardened rubber!!

I've made some progress already which I'll post once I get this thread started. Looking forward to getting to know some of you folks and learning from your experiences.

Vik

[Vinhead1957]

Looks like a great starting point

[Bankerdanny]

I bought a low mileage survivor a couple years ago, fortunately for me mine had been stored in better conditions, so the engine and exhaust were in good shape.

It looks like a great project though. Have fun!

[jtran000]

How do people find these bikes for so cheap???  The cheapest rust bucket around the bay area still goes for 1500!

[reddyvv]

Thanks for the welcomes. jtran000  - Craigslist is your friend 

As I mentioned I'm already a little ahead of my first post so I'll be posting a couple times with updates and my thoughts at the time until I get caught up to date.

I took the tank and exhausts off so I can start work on the engine and carbs. Seat is in good shape but the keys are missing so someone ripped the rubbers out of the seat lock to get the seat open. Also tried to get at the carbs by pulling off the carb to airbox rubbers. The rubbers and tool tray are missing. It has a new battery and spark plugs which I think the PO purchased with the hope that is all that would be required to get it going after 30+ years. Positive thinking

The cylinders were filled with motor oil which I siphoned out and replaced with copious blasts of Sea Foam. I can see rusty nastiness in all cylinders but #4 looks the worst. Looks like it's up on the exhaust stroke as I can see the valve open. I'll leave it to sit a couple of days while I busy myself with something else.

I took the carbs off to get them cleaned up and rebuilt. The exteriors are in decent shape and the bowls of three of them are in pretty decent shape with just some slimy goop in the bottom but #4 has a lot of rust -  major water intrusion from somewhere!! Maybe the airbox boots were taken off some time ago and the bike was left on the side stand allowing rain to fall on the carb?? Although the bike overall doesn't look like it was left in the weather very long if at all. O-rings on all of them are either crumbling or hard as rock. The emulsion tubes on a couple of them were an absolute bear to get out but fully dismantled now without any mishaps. That's a relief!! Looks like a thorough cleaning and rebuild is in order.

[Bankerdanny]

That's not rust. It's evaporated gas. The carbs are all aluminum and brass, no rusting.

[reddyvv]

That's not rust. It's evaporated gas. The carbs are all aluminum and brass, no rusting.

I wish that was the case but the rusted metal piece in one of the pics is the spring steel part that holds the main jet in place and one end of it is totally rusted away.

[reddyvv]

Okay, I'm way behind on my progress update so here is the latest.

I tried every trick in the book that I know of including the tips I found on this site but I cannot get these pistons unstuck. Since this bike hasn't been started in 30 years it looks like it'll have to come apart. I've ordered a cam chain splitter as one of the camshaft sprocket bolts is out of reach.

In the meanwhile I opened up the clutch cover to unstick the clutch plates which were frozen together as well. A little gentle levering between them with a screwdriver freed them up - I'll open up the basket and clean them up later. First priority is to find out how badly this engine is seized up.

[reddyvv]

I got the cam chain and the head off without too much trouble. The chain splitter worked great and although I was dreading seized nuts and broken studs all turned out ok. Geez, this engine looks like a mess. Thank goodness I couldn't get it unstuck or I would have been trying to start this engine up and God knows what damage would have resulted.

The worst rust is in #3 and #4 and I think one or both of them are stuck. All that liquid you see there is the PB Blaster and Sea Foam that I was using.

[reddyvv]

The process took me a few days of soaking and tapping on the pistons while trying to work the crank back and forth. The final assault took a good few hours to finally get the cylinders off!! The trick I saw on here of using ratchet straps to tightly pull the cylinders up away from the crank while giving the piston (#4 as it turned out) a judicious beating while working the crank back and forth finally paid off.

Free at last!!

The cylinders are in amazingly good shape, no rust or pitting at all. The pic is after I gave them a quick wipe with a rag. I was fully expecting a rebore to oversize but these should clean up brand new with a light honing. I am thrilled with the outcome 

[reddyvv]

Almost as bad as taking the cylinders off was removing the gudgeon pins. The circlips were rusted and frozen in place and were super tough to get out. It took me two days using a homemade puller fashioned out of some PVC pipe and assorted bolts (3 snapped) and nuts, heating the pistons, lubing the pins, etc before I was finally able to get them out. What a relief!!

It took me a further two days of soaking and some forceful levering to get the rings out of #3. Although #4 was the stuck piston it was #3 whose rings were frozen solid. The gudgeon pins have rings of corrosion around them at the gaps between the pistons and the rods so it's going to be new pins and rings all around. The pistons are in good shape and should clean up well - maybe some staining here and there. A quick inspection doesn't show any wear or scratches in the small ends from pushing out the gudgeon pins. I'll check them again when I get new pins.

[reddyvv]

Okay, this is the limit of my engine disassembly. Although the tops of the connecting rods have some light surface rust on them the big ends, the crank and the primary chain are well oiled and shiny without a speck of rust or corrosion. I dropped the oil pan and will thoroughly flush out the crank and the big ends to get out any crud and rust particles that fell in there while I was taking off the top end. It's a fairly straight shot to the outside with the pan removed so I'm confident I'll be able to get it cleaned out good.

A nice layer of sludge in the oil pan, I guess it's a good idea to get that off every year or two and clean the strainer as well.

[iron_worker]

Looks like that oil wasn't changed for all of the 8000 miles it ever went. That pan is nasty!

IW

[Tews19]

Great buy! great work freeing the engine from being seized and saving another 550 from years of neglect!

Subscribed!

[reddyvv]

I got started working on the front brakes and here is what I found. I took the caliper off and managed to get the opposing pad off but no way could I even budge the piston side pad. Lots of corrosion and jammed tight. So I connected the caliper back on, filled the reservoir which was empty, and pumped away. Lo and behold the pad and piston slowly came out, without even having to do any bleeding.

Here are some pics of the caliper and master cylinder after I took them apart, completely grunged up and rusted. I had quite a fight to get the circlip out of the MC. That's what 30+ years of sitting idle will do!!

I've put in a new master cylinder kit as the bore looked good after I cleaned it up. I had to order a new caliper piston as that was corroded and I've got all the caliper parts soda blasted and ready for paint.

[reddyvv]

I got to soda blasting a bunch of engine parts with a Harbor Freight el cheapo soda blaster and my tiny little Sears 3 gallon compressor. I don't know what was more annoying -- waiting for the compressor to charge up every 2 minutes, refilling the soda every 10 minutes or getting the fog out of my glasses every 30 seconds. But it all turned out good in the end and I preferred that kind of torture to scrubbing away by hand.

I found that Aircraft Stripper to loosen up the paint worked great before I hit it with the soda blaster.

[reddyvv]

The soda works great on the carbon, not so good on that crusty head gasket.

[reddyvv]

Did I mention that I have fallen in love with Evaporust?  It's either "God's gift to mankind", "the best thing since sliced bread" or as our British buddies would say "the dog's bollocks" 

Here are just a couple of examples and there were plenty more similar results. More extraordinary results to come...

[reddyvv]

Did I also mention how I hate the picture size restrictions on the posts? A 1 minute post turns into a 15 minute picture resizing ordeal. Almost as bad as scraping off a 38 yr old head gasket 

[goldarrow]

looking great.

use image hosting website to link up pics, like photobucket, etc....

[reddyvv]

I know. But it's still such a nuisance. I would rather just snap a pic with my cellphone and upload it right away. I would be posting a ton more pics in real time if I was able to. All these pics are taken with my cellphone, emailed to my PC, blah, blah, blah.. 

[goldarrow]

what phone to you use? most smart phone should be able to upload photos to photobucket site.  there is a limited amount of storage space if you use the forum to upload pics. 

[reddyvv]

Sorry I wasn't clear in my last post. I meant to upload the photo directly to SOHC forums rather than having to send it to photobucket first. Many forum websites allow you to upload any size photos and the web server automatically resizes the photo to whatever size they want to use.

[reddyvv]

My carbs are all rebuilt and ready to go. A big thank you to harisuluv on this website for hooking me up with a replacement unobtainium main jet holder spring which was totally rusted away - as seen in one of my earlier posts.

[SOHC4 Cafe Racer Fan]

Wow, those look like harisuluv's work!