1972 ct70 smoking

[robertct70k]

i overhauled my engine and it started smoking a little , the cylinder was initially honed with a 220 stone , so i pulled the cylinder out and honed it with a 320 stone grit and it didnt make any difference, i wonder if the smoking could be comming trough the valves ? thanks robert

 

[power6994]

Check the ring gap and make sure the rings are placed the correct way up

 

[robertct70k]

when i put the rings on there wasnt any markings on any of the rings ,and i did check the ring gap

 

[kirrbby]

when i put the rings on there wasnt any markings on any of the rings ,and i did check the ring gap

@ HOW TO PUT RINGS ON THE PISTON L@@K

dratv.com

Open up the last picture for a look. Good info IMO.
If the second ring isn't installed correctly... it'll pump oil into the combustion chamber.

 

[robertct70k]

thanks for the info , i am going to have to take it apart and and recheck , one thing i could tell you that the oil rings and the spring is a one piece unit , and i dont know if i should go with the conventional oil rings like the picture you send .

 

[kirrbby]

I'd stick with what you have. Honda used the 1 piece for those early years. But the oil ring just kinda helps oil the cylinder walls evenly...it does little to keep oil out of the combustion chamber.

 

[OLD CT]

Every piston ring I ever bought has a very tiny mark, THIS SIDE UP!

 

[robertct70k]

i just ordered another set of rings this time OEM, i am defenetly going to check for any marks on the two compression rings , on the oil rings i have never seen any marks on them, , thanks robert

 

[OLD CT]

Correct. No marks on the bottom scraper ring.

 

[lukelaw1]

when you overhauled, was the head also overhauled? if not the is a possibility that the exhaust valve seal is leaking

 

[OLD CT]

Like lukelaw1 said. It's a good idea to do a leak down test on the ports now, if you didn't already.

 

[robertct70k]

the head was redone by a shop but i dont know if an exhaust valve seal was installed ,when i disassemble it i will check for a seal , also i just got another set or rings OEM and there isnt any markings on any of the rings , one of the top compression rings one has a light color grey and the other ring is dark black , i am not sure which is the top ring , thanks for all the help so far , Robert

 

[robertct70k]

my apologies , i checked the rings again with a magnifying glass and there is a N marked on the compression rings , i will find out tomorrow when i disassemble the engine if i installed them wrong

 

[OLD CT]

Grey on top and black is the middle ring.

 

[robertct70k]

i did checked the rings and they were installed correct , i pulled the valve springs out and the green o ring seal was installed on top of the cup instead of on the bottom (in between the valve guide and the metal cup) i installed the seal in between the valve guide and the cup and put it back together and the bike quit smoking , by installing the seal on top of the cup allowed oil to be sucked down the valve guide causing the engine to smoke,

 

[OLD CT]

Thanks for the update!

 

[fatcaaat]

I recently sent a cylinder out for a bore. I got it back and it smoked. Took it apart to try and figure out what went wrong about 5 times and still smoked. Turned out it the cylinder (all cast) had tremendous porosity once it was taken out...like sand inclusions or something. Disappointing but putting another one on with piston stopped the smoking. You could just have a junk cylinder, could be slightly out of round, or could be tapered.