Meet my new 550f2

[mickwinf]

MMM not sure why its upside down will try again

[mickwinf]

i give up!

[SteveD CB500K0]

Did you take it on a phone?

[Green1]

Looking good Mick just need to get out on her now.
I still think you should have kept the old paint job a couple fish stickers and jobs a goodun. 

[mickwinf]

Steve the original pic was on phone but saved on computer.

[mickwinf]

well i had the first ride today, seemed ok at first but suddenly stopped with dead electrics. had a wiggle around the fuse box and it started but stopped again! another wiggle and managed to get home so a little more work to do but happy to be on the road. Oh and number 1 carb overflows.

[mickwinf]

After being off the road for a few weeks due to the tank problems in my thread tank liners, all back together so went out for a ride, only about ten miles to see how it ran, and actually went pretty well, it revs fine with no flat spots and ticks over nicely. BUT, there is always a but, it is smoking quite badly with whitish smoke. Now i did have diesel in there but not much and would expect that to be black. So whats the thoughts on this, do i need a top end rebuild? Money is tight at the moment so could do without this but i do have the gaskets already so probably rings and hope the pistons are ok.

[Bryanj]

White smoke is normally moisture but can ocassionally be oil does the smoke smell of oil? Could be stem seals as well or instead of rings

[K2-K6]

Diesel blows out while smoke when not burnt properly,( black when burnt but really overfuelled). Which is what happens (there's just not high enough compression to burn it and spark plugs won't light it off) with traces of it through a petrol engine.  It just sounds like it needs to clear it out of the system first,  give it a longer run and get properly hot it should clear out and not hurt it.

If it had too much diesel in it then it wouldn't fire at all. 

[mickwinf]

it is proper smoking! will refill with fresh fuel and try again

[Trigger]

If it is smoking under 2000 rpm but, when you rev it above when warm, then it is the piston to bore clearance or polished bores

[mickwinf]

today i checked the compression and all cylinders were about 170psi so would assume the rings and bores were ok, is that true? I made a short video on the phone, would i be able to upload it to the forum?

[mickwinf]

so put fresh fuel in and went for a ride but still smoking, probably will have to do a top end rebuild video https://youtu.be/PgLhtbpQbmQ
also battery not charging and have an oil leak!

[K2-K6]

Measuring the compression will give you a view of the top piston ring predominantly,  it's this one that is particularly forced against the bore as the piston comes up under load on power stroke.  The integrity of that seal is effectively what you are measuring.

The oil control ring at the lowest point of the ring pack is trying to prevent the oil being forced up into the combustion chamber,  also scraping it down as pistons descend. It's this function that would be in question as failure to keep the oil below it will give you burning under normal running. In reality,  burning "is" the test for this condition. Also, of course, the condition of valve guides comes into this area of oil control.

Also carefully check your breathers prior to commencement of strip down as both oil leak and burning are symptomatic of excess crankcase pressure.  In use,  any small pressure that escapes past the compression ring ends up in the crankcase and has to be vented to atmosphere to avoid the above situation.

As Trigger's post,  you are likely to find polished bores and may also have partly stuck oil control rings.  To correct that it would need to be honed if in tolerance prior to fitment of new rings.

Go with the breathers first,  that'll need to be checked anyway. Then assess again to see where you are.

[mickwinf]

I did have the cam cover off to re-tap some threads and breather was clear. The oil leak is from the cam end cap and seems to be the rubber seal, needs a bit of checking. Oil rings seems like a likely cause, looks like i will be busy this winter!