Author Topic: 1975 CB550 Sat since 1983 (Read 20080 times)

saxamaphone · « **on:** July 24, 2012, 02:36:20 PM »

Hello everybody, I'm very new to working on motorcycles but I've been learning a ton through this great forum.

I bought a CB550 at the end of June in pretty good condition with 9000 miles. It had been sitting since 1983. Original paint was even pretty good. The inside of the tank was pretty rusty and the exhaust is fairly rusty with some rusted out holes.

Any ideas for the exhaust? I'm trying to get this roadworthy as soon as I can because where I am, winter's always around the corner. I was thinking of patching with JB Weld until the winter and then looking into new exhaust options. I'd love the 4-into-4 but the new price is a little steep.

This is what came out of the tank when I got it home (bit of gas and water in there too):

There was rusty sediment but no leaks from the tank luckily. I filled the tank to half with Evapo-Rust and turned the tank every 4 hours or so.

Here's a before (you can't see the inside very well but you can imagine):

And after:

MrGardman · « **Reply #1 on:** July 24, 2012, 02:45:55 PM »

Looks like a nice project. One thing, it seems to be very complete and unaltered. Should be a fun one to do.

flybox1 · « **Reply #2 on:** July 24, 2012, 02:55:05 PM »

great looking bike there.

saxamaphone · « **Reply #3 on:** July 24, 2012, 03:01:01 PM »

It's been fun so far. My plan is to keep this as original as possible.

The guy I bought it from said he had rebuilt the carbs and the master cylinder and he had it running when I bought it from him. I soon found out that any work he said he had done was either poorly done or just a lie. I realized the front brake was pretty much frozen when I got it home so I cleaned out the caliper. It probably hadn't been touched in 30 years or more. The piston was being stuck by the seal in there so once that groove was cleaned out it started working well.

I've now taken the carbs off and I started to clean them. For supposedly having been just cleaned they were in really rough shape. They were all like the one on the right.

When I took the bowls off, I also was thinking something's missing. I realized none of them had the main jet. I've emailed the PO to see if he forgot to put them back in but haven't heard back yet. I had already emailed him about these air box parts that were missing and it turns out he had taken them out and not put them back in.

If the PO doesn't have the main jets I guess I'll pick up new ones.

I've only ever cleaned CB450 carbs and they are much more straight ahead. I have a pretty silly question about CB550 carbs. I'd like to keep them all attached on the bank and soak them so I've taken all the small pieces and rubber pieces out of the bottom to clean separately. In order to get the valve slide out do you have to take the carbs off of the bank?

Anyway, I'll try and keep track of the progress for anyone who is interested.

dave500 · « **Reply #4 on:** July 24, 2012, 05:01:24 PM »

remove all the brass and the slides from those carbs,use compressed air thru every hole every which way over a few times,,you dont want to be like everyone else and take them off fives times,note what jet numbers it has and where the needle clip is aswell,replace the fuel line and make sure the fuel tap and its screen are clean,you can remove and clean the gas cap vent aswell,its held in by a star shaped clip if you look close,go right over the ignition before you try and start it.

derelicte · « **Reply #5 on:** July 24, 2012, 05:03:45 PM »

Have fun, agree that it sounds like its gonna be a fun project. Dig that quilted seat actually.

LesterPiglet · « **Reply #6 on:** July 24, 2012, 05:05:42 PM »

No, you don't need to split the carbs to remove the slides.

dave500 · « **Reply #7 on:** July 24, 2012, 05:06:22 PM »

the main jets apear to be in place,they just pull out is it missing the leaf looking retaining springs?i cant see the idle jets though?they screw in,id split them anyway and replace the fuel tee o rings,,its a bugger if they leak a week or two after you get it running.

CoachDoc · « **Reply #8 on:** July 24, 2012, 09:42:39 PM »

Nice find. I'm thinking it may be a '75 because the paint on the tank is different in it's pattern than my '74 and the other '74's I have seen. That bike could be SO nicely restored. Please resist the urge to go the cafe or chopped route. Bikes that nice should remain stock IMO. All the info and expertise you'll need can be found right here on the forum. I put a Mac 4 into1 on my bike until I was sure of the success of my restoration. Now that Mac adorns Frosty's
550 in Aussie-land, and I have a beautiful new OEM 4/4 on my bike. Best decision I ever made. That exhaust defines this bike.

saxamaphone · « **Reply #9 on:** July 25, 2012, 12:04:30 PM »

Thanks all for the advice guys.

Coach-I'm going to leave this bike as stock as possible. I love them that way anyway. I'll probably get the Mac 4-1 exhaust for now until I can get the 4-4. I agree it gives the bike a lot of it's character. Most the photos I've seen of 74s do seem to have that the older paint scheme but the plate on the neck of the frame says 10/74.

Dave-You're absolutely right about the main jets. The photos I had seen looked like they were supposed to have a flat head slot for unscrewing them so I thought they were missing. They pulled straight out pretty easily.

I had already removed the idle jets and everything else so that's why they weren't in that photo. The leaf looking retaining springs do seem to be gone though. Do you have a photo handy of what they look like?

harisuluv · « **Reply #10 on:** July 25, 2012, 12:09:56 PM »

Yes for some reason these leaf springs seem to disappear a lot! Check my sig you will find some pics of what they look like.

Here are some I have for right now.

harisuluv · « **Reply #11 on:** July 25, 2012, 12:15:30 PM »

I took a pic from the side just now to show you what the profile looks like.

By the way as long as you're in there I would just tear them down completely. Sitting for 30 years can cause problems in places other than just the bowls. For example, you can clean out all the idles and main jets but it's possible your emulsifier tube is all gunked up. Would probably be worth it--as always, I tell forum members they can even call me if they get stuck on something, always glad to help. Number is in my sig.

saxamaphone · « **Reply #12 on:** July 25, 2012, 12:23:55 PM »

Thanks very much, very good shots. You obviously do great work!

The plan was to take everything out (all the brass, vacuum slides) and soak the rest as a bank but I'm having trouble figuring out how to get the vacuum slides out of the top. Then I can get at the emulsifier tube and get those cleaned up as well. The PO did say he cleaned them but with the tank as rusty as it was I thought I'd take them off and clean them as well as de-rust the tank. So they're surprisingly not too bad.

harisuluv · « **Reply #13 on:** July 25, 2012, 12:33:51 PM »

Once you have the caps off, there are two bolts which have little crush plates to hold them in place. One of those (7mm bolt) is what affixes the carb slide assy to the rod that is actuated but the throttle going up and down. There is a smaller bolt in there and that is one that you don't have to mess with for what you want to do. You have to just take a screwdriver and release the bolt from its prison and you can just unscrew it and the rod will come out. There are some multiple pieces on the rod including a felt washer so be careful. Here is the order of things on the rod:

harisuluv · « **Reply #14 on:** July 25, 2012, 12:35:54 PM »

If you don't have them all apart you might not have enough room to get them out, since the are all next to each other. What you can do to save yourself some time is just remove the 4 big brass nuts on the top. there will be a little metal pin and a spring in there. After taking that off, there is no more tension on holding them onto the rack and you can pull them off. Careful with the little rubber dustcaps as they are sometimes brittle. Just ease it off.

Tugboat · « **Reply #15 on:** July 25, 2012, 12:46:33 PM »

Those leaf springs are IMPOSSIBLE to find. And they hold the main jet in, so you can't run yr bike without them. Keep a lookout on ebay for a trashed set of carbs that you can cannibalize. Good luck!

harisuluv · « **Reply #16 on:** July 25, 2012, 12:49:19 PM »

They are indeed hard to find. I saw a member who used an actual spring to hold the jet in place. If you can't find them after looking around let me know. Don't know what the market price is on these things though.

Duanob · « **Reply #17 on:** July 25, 2012, 01:02:50 PM »

Really nice find. Sunburst orange is my favorite "colour" scheme.

Yes a spare set of donor carbs is a plus. Taking the carbs off the rack isn't the end of the world and if the bike has been sitting for almost 30 years there is a good bet all the rubber o-rings and fuel lines are deteriorated. They will need to be replaced in between the carbs at the fuel T. Take the slides out and make sure your needles are clean with no deposits where the needle fits into the jet.

saxamaphone · « **Reply #18 on:** July 27, 2012, 11:54:50 AM »

Hi guys, the carbs came out very clean but in the process I discovered that one spring from the air screw is missing. It was gone when I first opened it up.

I'm thinking of going to hardware stores and auto shops and seeing if they have anything that could replace it? Has anyone had to replace just those springs? All the jets and everything are otherwise in great shape.

J

harisuluv · « **Reply #19 on:** July 27, 2012, 12:19:17 PM »

Yeah the spring just puts tension on the screw so if you found one the right size and about the right tension I would say it would be fine.

saxamaphone · « **Reply #20 on:** July 27, 2012, 12:33:43 PM »

Good to hear. Thanks again.

J

SohRon · « **Reply #21 on:** July 27, 2012, 10:44:22 PM »

Quote

the plate on the neck of the frame says 10/74.

10/74 would be a 1975 bike as the model years ran from July to July (7/73 - 7/74 = 1974 model year, 7/74 - 7/75= 1975 model year, etc). Later years actually state the model year on the tag, but these early ones give only the build date. Check the VIN on the plate and frame; it should start with "12XXXX..."

Tank decal and paint is for a '75 as well, in addition to the (missing) foot on the kickstand, "Highbeam" plate on the bar clamp, and so on. Definitely a 1975 K1.

Looks like a nice bike in good condition. Good on you for keeping it stock; it'll be worth a lot more in the long run.

RAFster122s · « **Reply #22 on:** July 27, 2012, 11:18:21 PM »

Looks like the front signals are the ~~early smaller ones~~ right ones...same as rear while ~~the rear are the large ones~~ they went to the large signals in 75. 74 had ones about an inch smaller diameter and the lense was domed as well as a different shape for the rear of the signal body.
Mount location was same/same fork ears. Later 550k dropped signal location to bottom of fork ears.

Tews19 · « **Reply #23 on:** July 28, 2012, 07:53:03 PM »

Nice find, subscribed!

harisuluv · « **Reply #24 on:** July 28, 2012, 11:35:33 PM »

Wish you had discovered the missing screen sooner, I woulda included it with the float bowl. Hope you found one.

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Author Topic: 1975 CB550 Sat since 1983 (Read 20080 times)