1977 Cb550f blue smoke

Hello! My names lee and I'm kinda new to the forum.

I just recently acquired a 77' cb550f with the 4 into 1 From a guy that used to have the bike in Minnesota. It only has 13k miles, in immaculate shape but I can tell its sat for a while because there is a flat spot on the front tire. Sad because the tires practically brand new. Anyways, when I test rode it at his place in Austin tx, I didn't see any smoke or any signs of smoke, Although cylinder 1 was not firing. I felt confident it was a carb and valve adjustment issue so I bought the bike.

Got it back to my place in Houston and immediately took it apart to adjust the valves back to spec and tear down and clean the carburetors really good and cleaned the spark plugs and changes plug 4 to plug 1 since I knew 4 was ok.

Fired up on all fours and I was ecstatic. Until I started to head a clicking type sound, and when the clicking occurs the RPMs drop. Also it started smoking bluish smoke out of the exhaust, mainly after the bikes warm. I don't see any smoke on cold startup. My first thought is valve guide seals on cylinder 1.

I can upload a sound clip so you all can get a glimpse at what I'm talking about.

Hopefully I can get some advice and experienced guidance!


Thanks,
Lee

Blue smoke is oil. Did you do an oil change? Clicking sounds is prolly valve adjustment. On cold engine the intake is 0.05mm and the exhaust 0.08. Exhause gets hotter, thats why theres more play. Clicking sounds can also be timing chain being loose, or the bolts holding the cam chainwheel. Anyways. Blue smoke is oil. Either valve seals or rings are done.

if I bought some new valve seals and take the engine out, is it a weekend project?

I've adjusted and rechecked the valves and they are still in spec. Taking the carbs off to replace the main jet seals, (#2 decided to come a little loose) and re adjust the points. This should hopefully resolves the slight miss fire and then I'll do a compression test to see if any cylinder is low. Then I'll do a leak down to determine if my seals are bad and if the valves need lapping.

If the tires had flat spots, I'm pretty sure the rings were seized to the cylinders. If the cylinders weren't soaked with oil before being fired after storage it is likely that the rings were damaged. Either way it is definitely burning oil.

To change the rings I'll need to remove the top end and what not so I'll lap the valves and replace seals while I'm there. What else needs to be taken care of while the top end is off? Trying to plan this all out so I can knock it out in a week or so.

And a compression test will show if I have damaged rings correct?

Yes.

Diffucult to say. Shit can be so crapped you'll need other parts wich you didnt order...

lapping valves is only viable for a TINY clean-up or final matching
you can't just lap,lap, lap away to try and create a seal for worn valves and pitted seats you will end up with seats too wide
you also need to check all of the valve guides and valve stems for wear this can be a place that oil comes from as well as stuck/damaged oil control rings
for example i have torn down at least 8 cb/cl/sl350 engines and they all but 2 had valve guides worn out beyond usable spec

With only 13k miles I would assume that the valves would be ok but your right I can't just lap away and hope it fixes it.

However I looked online for new replacement valves and couldn't find any. I found the seals and everything but not the valves.

If I open the top end I might as well replace what I can so if someone and give me a write up of what all need to be replaced as a general guide that would be great. I've never done top end work on a bike like this, only dirtbikes

13k is not a lot,they may be just fine
just a good idear to check the guides as per fsm
you might want to replace the cam chain and guides/rollers for it as well the rubber gets old and cracky

Can I do valve work on these bikes without pulling the engine? I know piston work I can't but it looks like theres a decent amount of room to pull the valve cover

i have puuled head and barrel off a 500 four with motor in frame

Oh sweet. I was not looking forward to pulling the engine. Did it on my 450 by myself and that was not fun haha.

Thanks for your help xb33bsa, your the man.

Before you start tearing shit down i would strongly recommend an oil change an a few good hard runs to loosen things up. This stuff happens to bikes that sit and rot.
My xs used to smoke like crazy when i bought it.
3 oil changes later and a thousand miles later it no longer smokes and comp is up on all 3 pots.

I changed the oil as soon as I got it and have put 300 miles on it already and it's gotten worse instead of better.

I'm going to do the valve seals before I completely tear it down to see if that can take care of it.

if yer pulling the head you may as well go with new pistons and a fresh bore
on the rare chance the bores are still ok then rings could do it...
the 350 hondas don't even have valve seals and they don't smoke (much anyway)it is way way way more likely to be stuck/damaged oil control rings

I was planning on trying to do the valves with the head still on, I use it to ride to school and back so I need to make it a weekend project. If the valves aren't the answer then I'll need to do the full top end

you are just making nearly double the work for yourself
i guess you are going to airpressure the cylinders to get the seals off,if you pull off the first 2 seals and they arent totally shot ,cracked hard and falling apart then you need to accept that it is the rings and not make so much extra work for yourself
good excuse to buy a reliable bike and take the time to do the 550 right the worst mistakes happen in a rush

Pulling the valve springs from a bike engine without the head off is not fun.