Topic: 1977 cb550K project - Tachometer

[Seattle_Fauxpster]

Hey all,
This is my 2nd post. I just bought a 1977 cb550 K (see below). Here are the issues I'm having and my thoughts on them.
1. When I try to start the bike, with the choke fully out, I'm definitely getting something, but it sputters out after a couple of seconds. If I try to give it any throttle it immediately dies (it doesn't even sputter for a bit).
2. The number four carb is is leaking like a tap into the reserve line, but the number four exhaust gets hot.
3. The number 2 exhaust stays cold (this is actually new, I'm pretty sure this wasn't happening when I bought the bike - possible spark plug failure).
4. I've done a compression test and all four cylinders had good compression (right around 150 psi, when it was cold)
5. I'm leaking oil out the bottom.

I don't expect all of these issues to be addressed immediately, I'm pretty sure I should start with the carbs and work my way forward but does anybody have any thoughts or ideas?

Thanks in advance.

[Seattle_Fauxpster]

Here's the pic.

[flybox1]

welcome.  start with downloading the shop manual for the 550, and read up on the 3000mi maintenance items.
typically, most issues will be covered in these step by step procedures.

[Bankerdanny]

First. welcome.

Random thoughts:

As soon as the bike fires back the choke off slightly. At this time of year the bike should not need the choke for very long period, and full choke only to start.

The leaking carb is (1) a malfunctioning float or float needle (2) a crack in the overflow pipe or (3) a faulty drain screw. I had the cracked pipe in my '77 55K, it's a fairly common issue that can be fixed sevral ways.

Did it run properly when you first got it? Has the bike been sitting for a while?

If the bike sat for a few years then you will need to get a carb gasket kit and pull the carbs and clean them. The cleaning part will take a couple days for a novice, but is not difficult. Removing and reinstalling the carbs however is a pain in the ass, although with practice and proper technique it gets easier.

Don't worry too much about the carb synch at this point, it's the last thing you deal with after you have freshened the carbs and done the 3,000 mile tune and adjustment.

The '77-'78 K carbs are different than the '76 and earlier, and are easier to bench synch. The #2 carb (2nd from the left when you are on the bike) is non-adjustable. So when you vacuum synch it's the reference carb. The benefit for a bench synch is that you can eyeball the slide level and then match the others to it.

When I did my carbs they were in almost perfect synch and I didn't actually make any adjustments.

Leaking oil out the bottom where (I assume you mean the bikes bottom and not yours, which would require a visit to an entirely different board)?

[Seattle_Fauxpster]

The bike was running when I first got it. I let it sit for two weeks without trying to start it (because I needed a new battery). The bike has definitely not been sitting for years, the guy I bought it from was using it as a daily commuter, but his girlfriend was forcing him to get rid of it to help finance the new Beamer he just bought (at least that was his story, I'm sure the fact that it was starting to not run smoothly played into his decision).

The overflow tubing is fine, it's only when I take it off that gas pours out.

[Bankerdanny]

So when it is parked and not running, but with the fuel tap on the on position, no gas comes out of the overflows?

[Seattle_Fauxpster]

No gas comes out of the bottom of the bowl even when the gas is off and the bike isn't running (presumably there is gas in the bowl that would eventually drain completely. I think the overflow line (which is capped on my bike) is itself full, so when it is on the carb, the carb can't drain completely.

[TwoTired]

The overflow tubes (carb bowl drains) are not supposed to be capped...ever.

Check the oil for gasoline dilution.

[Bankerdanny]

Fuel coming out the tubes is not a normal part of your bike's operation. It should only come out of the drains if (1) a float is stuck or the needle isn't seating properly (2) the tube is cracked or (3) the drain screw is loose or its o-ring is damaged.

If all those parts are in good shape and functioning properly there is no reason gas should come out the tubes.

[Duanob]

Here's the pic.

So you're the one that bought that bike. I hope you got a better price than what he was first asking for it.

Yeah its been said. 3000 mile tune up first. Then carb cleaning. If the carbs are leaking fuel then they need to be gone through. Recheck your float level and float jets and all that. If it was running good before it will run good again, no worries. Just takes time and effort. There is a manual you can download from this site for specs and how-tos. Also the FAQ section and Tips and Tricks section are a great help.

Oil leaks: common causes if coming from the chain cover, shifter shaft seal, primary shaft seal, 3 o-rings that seal the oilpump. None are expensive or hard to change.

If coming from the end of the heads, 2 little oil passage o-rings, the head has to come off. Not a big deal to live with but annoying. Shouldn't effect the way the bike runs or oil pressure.

Also around the head or cam cover, the tach cable seal o-ring, 6 oil seal pucks under the cam cover.

When taking the cam cover off and re installing it always remember the rubber band trick. very important. See pic below.

[Bankerdanny]

You know, I didn't realize that the rockers attach to the cover and not the head.

I never needed to pull the cover on my 550k, and hadn't gotten around to the 550f yet, although I have the gasket and it is on my agenda.

That's a bummer as I would looking forward to being able to easily reach the rockers to adjust the valves while the cover was off. Oh well, at least the engine is out of the frame, which will make it easier than if it were in the frame.

[Duanob]

Yep impossible without the cover on. If you don't hold the rockers up out of the way when installing the cover they can bend valves and in turn break valve guides when you go to start the bike. I wish the PO on my bike would've known that.

[Seattle_Fauxpster]

So you're the one that bought that bike. I hope you got a better price than what he was first asking for it.

I got better than asking price but it took a while, and I probably should have brought him down further, but I figure I'm only out $150 for stuff I haven't foreseen so far (I basically counted on rebuilding one or two of the carbs, and maybe replacing all the seals in the engine).

If the carbs are leaking fuel then they need to be gone through. Recheck your float level and float jets and all that. If it was running good before it will run good again, no worries. Just takes time and effort. There is a manual you can download from this site for specs and how-tos. Also the FAQ section and Tips and Tricks section are a great help.

Yeah, that's my next move. I'll keep everybody posted on my progress. Thanks for everybody's suggestions. I think I'm set for the next week or two.

[Duanob]

I got better than asking price but it took a while,

Good job! I thought he was crazy asking $2500. The wheels and paint are nice but that seat has got to go And those pipes, I would just get a 4 into 1 eventually.

Let me know if you need any advice on removing the carbs. I don't think the 77 is any different than the 76.

BTW what part of town are you in.

[Seattle_Fauxpster]

Good job! I thought he was crazy asking $2500.
...
BTW what part of town are you in.

You might be thinking of a different bike, because he was asking $2000 from me and I got him down to $1800.
I'm in Ballard. You?

[Duanob]

His first ad I remember it was definitely $2500 probably a month or so ago. I thought he be crazy man.

I'm in west seattle, you are close to Backfire Moto, next wednesday night.

[Bankerdanny]

The '77K is the first year of the PD46 carbs. Not the same as the '76 and earlier K bikes. The basic removal process is the same though.

You shouldn't need to 'rebuild' any of the carbs. Jets really don't wear out and it's rare to find a bike with enough miles to have worn throttle shafts or slide needles. Generally what they need is what I think of a 'freshening', which is a good cleaning and new gaskets and o-rings. And you will be wanting to do all 4, trying to get away with only 1 or 2 of them is just asking for trouble.

[Duanob]

What BD says, Just buy the gasket kits its a lot cheaper. THEN if you need new jets you can find them fairly cheap at jetsrus or sirrius (?) or from members here.

[Seattle_Fauxpster]

The '77K is the first year of the PD46 carbs. Not the same as the '76 and earlier K bikes. The basic removal process is the same though.

You shouldn't need to 'rebuild' any of the carbs. Jets really don't wear out and it's rare to find a bike with enough miles to have worn throttle shafts or slide needles. Generally what they need is what I think of a 'freshening', which is a good cleaning and new gaskets and o-rings. And you will be wanting to do all 4, trying to get away with only 1 or 2 of them is just asking for trouble.

Thanks. Especially about doing all four, I was just going to do one, but not now.

[Seattle_Fauxpster]

I definitely need some help here.
I've taken the carbs off and everything seems good except one major thing: The fourth float bowl has a crack in the bottom, when I spray a small amount of cleaner in the bottom it drained and I can see the crack in the bottom, it clearly is going to need to be replaced, but I'm a little worried, as I can't really find replacement bowls for a 77  cb550K. It definitely looks like this:

http://compare.ebay.com/like/121124922229?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

But the bottom looks a little different. Does anybody know where I can find one?

[bollingball]

Fuel coming out the tubes is not a normal part of your bike's operation. It should only come out of the drains if (1) a float is stuck or the needle isn't seating properly (2) the tube is cracked or (3) the drain screw is loose or its o-ring is damaged.

If all those parts are in good shape and functioning properly there is no reason gas should come out the tubes.

I don't think he is sure what tube you are talking about. Tube inside bowl or drain tube.
Ken

[bollingball]

Contact http://forums.sohc4.net/index.php?action=profile;u=16522
He will be able to help I think.
Ken

[Seattle_Fauxpster]

Contact http://forums.sohc4.net/index.php?action=profile;u=16522
He will be able to help I think.
Ken

Hey, thanks. Will do.

[davidtime]

Here's the pic.

So you're the one that bought that bike. I hope you got a better price than what he was first asking for it.

Yeah its been said. 3000 mile tune up first. Then carb cleaning. If the carbs are leaking fuel then they need to be gone through. Recheck your float level and float jets and all that. If it was running good before it will run good again, no worries. Just takes time and effort. There is a manual you can download from this site for specs and how-tos. Also the FAQ section and Tips and Tricks section are a great help.

Oil leaks: common causes if coming from the chain cover, shifter shaft seal, primary shaft seal, 3 o-rings that seal the oilpump. None are expensive or hard to change.

If coming from the end of the heads, 2 little oil passage o-rings, the head has to come off. Not a big deal to live with but annoying. Shouldn't effect the way the bike runs or oil pressure.

Also around the head or cam cover, the tach cable seal o-ring, 6 oil seal pucks under the cam cover.

When taking the cam cover off and re installing it always remember the rubber band trick. very important. See pic below.

I have never seen anything with this set up and I wish I would have known the rubber band trick when I put mine back on. I might take it back off to make sure its right. Haven't started it yet. I just slowly tightened and moved them as needed until it seated properly.

[motosan]

Contact http://forums.sohc4.net/index.php?action=profile;u=16522
He will be able to help I think.
Ken

Out of curiosity....wouldn't JB Weld work to fill the crack?  That might be a possible cheap fix...maybe...