engine smoke

[baz]

Hi got my a10 out of the shed yesterday where it has been idle for 12 years i drained the sump the oil had all run from the oil tank into the sump i started the engine second kick it ran ok but its smoking the oil is returning to the tank but it just wont stop smoking i checked the sump agan after running the engine and there was about half a small cup came out the compression feels good anyone got any sugestions before i tear it down to check if the rings are stuck? the bike didnt smoke when i storred it i used 20/50 oil the same as i always have cheers baz

[bsa-bill]

I think if it was my bike I would risk a short run to see if it stops smoking, after 12 years I would not be surprised at a bit of smoke my Flash usually smokes on one side for about 1/4 of a mile then clears.

[baz]

you may be right but the smoke is quite bad i looked down the spark plug holes and i can see oil on the inlet valves! and the crown of the piastons looks oily i did a compression test and it was showing 140psi both sides with the engine hot i think i will pull the top end off to satisfy myself baz

[muskrat]

 I'd give it a few more miles Baz. Rings will take a while to bed back in and the valve springs may be a little weak. Recon if I sat still for 12 hours let alone years I'd be a bit stiff too.
Cheers

[baz]

i decided to bite the bullet and lift the head and barrel i found the rings were badly worn out and sharp,the funny thing is i dont remember the engine smoking when i last used it but i was running it very rich to try and keep the engine cool to stop it from cutting out when hot,i guess i washed the oil away in the bores hence the sharp piston rings,i have a re built magneto and advance retard unit ready to fit so hopefully the overheating problem will be sorted this time around cheers baz

[Triton Thrasher]

i was running it very rich to try and keep the engine cool to stop it from cutting out when hot

I think that's an unusual way to address a cutting out when hot problem.

[baz]

well the bike would only cut out when i was thrashing it  throttle full open so i went up on the main jet,when ridden normaly it was fine in traffic etc at low revs i am going to fit the new magneto soon i have read on some posts here that 5/16" btdc full advance is being used to good effect on a rocket spec motor is this correct? i think from memory mine was set at 3/8" cheers baz

[muskrat]

 G'day baz, 3/8" might have been a little advanced and caused pinging & extra heat, which in turn closed the valve clearance propping open a valve or two.

[baz]

Ok the engine is up and running again new rings fitted new magneto and advance/retard unit timing set at 5/16" btdc monobloc 389 re built from all the best bits i had! 106 pilot type D needle 20 pilot jet 3 cutaway slide 250 main jet needle position 3 ,i have left the tappets slightly loose 10thou in and 12 thou out(alloy head) i will adjust these when i re tighten the head ,engine fired second with just a little smoke and ticks over and revs out well i am going to fit a pancake air filter to it and as soon as i can get it MOTd i will put some miles on it to see if i have cured the overheating problem cheers baz

[baz]

done about 150 miles now since the mot the bike is running really well no smoke or cutting out as yet very pleased with it the worst thing i have got is a leaky chaincase and the clutch slips a little i need to break the rings in a little more because i want to do a full throttle plug chop as i feel it may be lean on the main jet,,,,,,,,,,,,,cheers baz