Topic: Oil Leak and constant white/blue smoke

[PyroVee]

Hi there guys, I am new to the forum and this is my first post.

I have recently purchased a CB550 four and am having a couple of issues, this bike is very new to me and I am relatively unfamiliar with its workings. The main issue for me so far is that there is a small oil leak on the left hand side of the engine, visible on the fins, in addition to this there is a relatively constant white/bluey smoke coming out of the exhaust. I have checked the spark plugs and for all intents and purposes they seem fine, not fouled. I recently put a semi synthetic silkolene 10w40 in there and that only seems to have made it worse. My first guess would be to do a compression test. According to the previous owner the engine was rebuilt 1000 miles back, cam chain seems very tight on the tensioner so I guess there is SOME truth to this, perhaps the valve rubbers are on their way out?

The second issue is that it "bogs" in mid range acceleration, lower revs it runs fine, high revs too however in the middle of these two it chugs.

Any advice would be brilliant!

[calj737]

The oil leak on the fins (speculating here...) is often attributed to the rubber pucks beneath the valve cover, that in turn cover the studs. If the PO re-used the originals, they were probably dried out and are no longer sealing properly.

It could also be the O-ring/gasket of the valve cover itself. To identify the source, degrease the motor and get it clean. then apply some baby powder or talcum powder to the seams of the valve cover, head/cylinder seam, and especially at the ends of the valve cover where the camshaft covers are. (There are O-rings on dowel pins beneath that part and they too are especially prone to weeping oil).

If the oil you used is NOT rated for a motorcycle with a WET CLUTCH, then drain it, replace the filter too, and use new proper oil. Motorcycle oil is more specialized than car oils. Your clutch discs (right side, by your foot) is bathed in oil. Many car oils have friction modifiers in them and these are not compatible with a wet clutch (motorcycle) vehicle.

The blue smoke could well be the valve seals or valve guides. The seals are rubber "caps" on top of the stem and if the PO rebuilt the engine poorly and didn't replace these, or the guides (sleeves the valves ride in) then oil leaking into the combustion chamber is likely. It could also be a symptom of a broken ring, poor rebuild generally, etc. Hard to say with the limited info provided.

The "stumble" in midrange throttle is likely down to carburetor/induction changes. Is the bike running "pods" or the stock airbox? If pods, then welcome to hair pulling tuning.  Maybe you can provide more detailed info, or, link some photos to this thread showing the carbs, air filters, and any clean, focused shots of the plugs, and the oil leak area. A side view of the plug showing beneath the electrode strap is best.