76´CB550F, born to run, currently rehabing

[Bigbird]

Hey people, greetings called from fresh forum member

Many thanks for all the exciting readings, that helped make me go for it. Hereafter; my first machine on two wheels bigger than 50cc:
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I´m turning to this incredible forum for some help on the diagnostics side, because i´m pretty fresh on SOHCs.

Has:
- paint job
- custom grips, taillight, speedo from wrenchmonkey
- Marshall Deeptone exhaust
- cheap podfilters, which it got without being carbsynced and hasn't been running much since
- tendency to overheat
- strange sounds (will post video)
- some oil leaks
- a good life coming

Needs, in suggestive order project starts at:
- gas tank clean
- inline gas filter
- timing
- valve adjust
- carb clean/rebuild
- carb sync
- possible cosmetics at some point

I´ll keep you posted along the way incase there are interventions or a good tip you want to share.
First of, later tonight, will be a video of the machine running. If you have any thoughts, feel free to share!

Cheers, good folk

[mickwinf]

Hi and welcome to our forum, you will find lots of help here to get your bike sorted, model and pics will help.

[matthewmosse]

I think you will at the least need to re jett to suit the pod filters and exhaust, I tried a similar setup at one stage and it was a case of lots of re jetting and spark plug chops or revert to a standard air filter - I went with the easy option and bunged the standard filter back on and it ran better. Pull out the sparkplugs and hopefully that might shed light on the overheating - I suspect it's running lean if overheating and aftermarket filters. I'd also do all the servcing jobs like camchain tension, points - tappetts etc before worrying about the carb syncing to be sure that is all spot on. Oil leaks can be sometimes ignored unless bad, but may indicate a deeper problem - my first big bike was a cb550k3, leaked oil, turned out it had a bad engine rebuild using instant gaskett goo and old reclaimed gasketts - back in those days I was keen and had the motor appart and half decent used spares bunged in where needed ready for a ride to Scotland the next day. Taught me a lot that bike did, though I'd have done better with this forum to consult, I only found it later on, much later on.

[Bigbird]

Thanks for the answers, great to finally get started. I will be much safer building this thing with this thread on my back.
Following is a pre-tuning video, i´m getting started with the tank, timing, valves and carbs, but the clunky sounds and oil-lamp are more of a pain. I´ve been reading bout oillamps staying like this for years, but together with the clunky sounds could it be some bearings in the transmission? I recall reading about a connection there. Its got oil to the top, and the leaks aren´t too bad, but i would like to get an opinion about that as well. Post some more about that tomorrow. I´ve been thinking to change the oil to 15w40 to see if the clunk will disappear in high hope, but I see I might be facing the engine-pull here.

Thanks again

[flash]http://www.youtube.com/v/AzuKLNnJ4kI[/flash]

until i learn to build in youtubes:
http://youtu.be/AzuKLNnJ4kI

[UK Pete]

Hi and welcome to the forum, well done you have now become a SOHC nut like the rest of us, good choice of bike
pete

[florence]

You probably don't need to worry too much about the clunky sounds.  These engines sound lumpy at the best of times, especially from the clutch, at low revs.  Having the carbs out of balance and incorrect ignition timing simply conspire to make things sound even worse. 

Twenty years ago, I worried about mine.  To the low mileage (7k) engine I bought from the states, I fitted new cam chain, tensioners, rebore..  The only reason I put in the camchain etc was because I had stripped the engine to inspect as it had been standing for a while.  It seemed sensible to put in the new parts while I was in there.  In fact it was like new inside.  Well anyway my point is, it sounded lumpier than I would have liked but with regular oil changes, it hasn't grown any worse twenty years later.

I would start with the ignition side first, new plugs, points and set up ignition timing, then move on to carb balance and then jetting for the exhaust/filter combination. 

On my CB500 I have SM air filters and Laser 4-1 exhaust.  I use 110 for the main jet (standard is 100) and it runs very sweetly indeed.  I can't remember the needle position but I think it is in the middle.

Here is my bike as captured in my garden by Steve D, our kind host.

[Green1]

Welcome
She sounds just like any other SOHC Iv ever heard.
I was once lectured by an old boy on lack of maintenance and how young scaly wags like me don't look after anything.

I wonder if it was Bitsa on a day trip over here.

Mick   

[tom400f]

Sounds ok to me.

Not unlike: https://www.youtube.com/watch?v=Ja_kAeU2pd0

[Bitsa (Ralph Wright - RIP)]

Mick
Naw wernt me mate I dont try and tell the young anything most all ready know it all
Cheers
Bitsa

Bike sounds good to me fine tuning maybe

[Green1]

Oh yea forgot to mention apart from the misfire.Agree with oddjob a good tune up works wonders.
If it doesn't sound like it's chewing it's head then it's not a 70's Honda.

Mick

[K2-K6]

Hello Bigbird and welcome to the forum.

The first thing you should do is change the oil and filter if you are at all unsure of the oil condition/quality that's in there. You can argue with people  for ever abut what oil should be in there and get 100 different answers but what ever it is, if it's been diluted with petrol from crappy running, then it will be no good for the engine.

Pod filters basically change the vacuum that is pulled at the intake to the carb and it's the difference of the vacuum compared to atmospheric in the float chamber that causes the jet to flow a set amount of fuel. Change the vacuum and the jet will flow more or less fuel......but, and it's a big but.....the engine requirement didn't change, so wrong fueling and crappy running is the result. A quick reality check can be made by wrapping some porous rags (polishing cloth/muslin or similar) round the pods and see if the restriction improves the running.

[Bigbird]

And now i´m back to let you know i can really shake em down.

Thanks for the warm welcome, and astonishing response. Getting back to the Honda-project for a while now. My aim has been a longdistance (4000km) trip in the end of summer, but that´s really in the grey now, as i´m growing to the needs of the bike.

I Did:
- tank
- points
- timing
- chain tension
- valves sounds ok, so i left them as is

Now cleaning carbs, which didn´t look too bad, except thin white deposits on the two leftside carbs. One needle had a bad screw and i tried to bore it out but didn´t succeed, so now i´m looking for a single needle and throttle slide, if anyone near Copenhagen has such a thing I´d be happy to pick it up very soon. I think I´m keeping the airfilter for now, as an airbox is hard to get by.

Oilpressure-light, which comes on gradually as the bike heats up.
I´ve been carefully listening to the engine, and the sound changes of course when it gets it´s heat on, but that I figure is normal. No bad sounds, other than when it gets really hot from low speed city driving, it stumbles and using the kickstarter feels heavier.
I ear-synched the carbs, and it runs alot better, almost no stumbling when hot. Can´t remember if the heavier kickstarter remained or not.

As for leaks
Topend looks moist most of the time, drips from back of block once every 5-10 minutes when hot. Filled it up with oil 400km ago, and i can hardly tell its changed. Engine bolts are a bit rusty, so there is rust trails on the enginecovers from the top and down. Suspecting leaking carb here, as oil tends to a gasoline smell again, so i´ll change the oil again after the carbs are back on hopefully without a leak. Using 10w40. While changing the oil I´m fitting new gaskets to sidecovers of engineblock.
Checked for airleaks with both starterspray and a small gas blow torch. None.

Plugs (fairly new)
Cleaned and checked gap; and again black sooted after run, which points to a rich running, but it should be running lean as i haven´t rejetted yet. Needles where set to second highest which would make it even leaner. Will try to resitrict the filters as soon as the carb is back on and synched. So, can the black plugs point to oil burning? Bike is said to have 45000km on it, is it time for a top end service? Guess i´m going to do a compression test to see what condition the pistonrings are in.

Exhaust
Has been white at one or two occasions. Clean when idle, black when revving.