oil burning tbird

[thunderbird]

i have just overhauled the top end on my tbird due to it burning oil excessivly.when i removed the barrels i found the oil control rings had siezed in there grooves on both pistons and also the second comp ring on the primary side this was the side smoking worst so it all made sense this was the problem,the barrels were good no ware lip or scoring just required a light hone,so i decided to just replace the rings, after cleaning the grooves in the pistons i found the new rings were also a little tight in the grooves on the control rings both pistons and second comp ring primary side the tight spots were to the front and back of the pistons, i managed to scrape the grooves out a bit more until all the rings were free and reassembled the top end.

now having fired the bike back up and taken it for a few runs it does appear to be smoking /burning oil on the primary side still but not as much,i also fitted new valves and guides, the rings were gapped to the cylinders and are fitted the correct way up so the only thing iam thinking is should i have replaced the pistons as well?is it possible they have destorted closing the grooves up,they are AE fed mogal so a good make but do have a  continual cut out front and back in the control ring groove rather than drilled holes is this a weak point on these pistons,any advise appreciated as iam about to strip it down again and replace the pistons.Thanks steve

[Rex]

IMO you haven't given it enough time to run in.
Sounds like you've done and checked all the obvious things. Did you oil up the bores before starting? I've taken to doing something the old Norton race team used to do, namely assembling the pistons into the bores with the merest hint of oil, and giving it a handful when you fire it up. Sounds brutal, but sure gets those rings bedded in quickly.
Some like to smother the pistons etc in high quality synth oil, and then wonder why those rings won't bed in and the engine still smokes....

[thunderbird]

thanks for your reply rex,i had just got the bike out of  the garage to start striping it down and rain stopped play not a lot of room inside with all the junk i have .perhaps i should give it a bit more time but i was bit concerned as it was smoking a fare bit on the primary side but ok on the timing side and that was the side the control ring and 2nd comp ring were seized in which i think was more to do with distorsion of the piston grooves rather than carbon build up i was carefull on assembly to insure the new rings were free on this side but had to scrape the grooves a fare bit with a broken ring to ensure this.
yes everything was well oiled on assembly and i have added some upper cylinder lube to petrol to help things settle in.so perhaps i have over lubed it yesterday when i fired the bike up there was no smoke from either exhaust but when i came back in from my test run it was smoking from the one side. thanks again steve