blueish smoke??

[honda400ex01aca]

my friend 300ex is smoking blue out of the exhaust and burnin oil faster the a 2 stroke.. he put a new head and seals and rings on it. what else could be the problem???

[86 Quad R]

did he bore or hone the cylinder when he freshened it up or just stick rings in there?

[GRASSHOPPER71]

i would say if he didnt bore the cylinder,, thats the problem. 95% of all rebuilds on these engines,, the cylinder would need to be bored.
just replacin the rings won't do it.

[Ruby Soho]

no, the cylinder needs to be HONED not bored.

fresh hone + new rings, new valve seals and such will solve all oil burning problems.

i just went through this on my 110.

[GRASSHOPPER71]

WELL I WOULD SAY YOU ARE ONE OF THE 5% THAT IT WORKS. WHEN I DO A TOP-END OVERHAUL,, IF THE CUSTOMER DOES NOT WANT TO BORE THE CYLINDER AND JUST PUT RINGS IN,,, I WILL DO IT WITH NO WARRANTY......
REALLY,,, IF I'M A LITTLE BUSY AND HAVE SOMETHING TO DO I WANT EVEN DO THE JOB. BECAUSE WHEN THEY LEAVE AND A WEEK OR TWO MAYBE EVEN THREE WEEKS DOWN THE ROAD IT STARTS SMOKIN AGAIN,, THAT LOOKS BAD ON ME THEN, SO I RATHER NOT EVEN DO IT.

[Ruby Soho]

you bore it if you want an overbore piston. unless the rings wore into the sleeve or something, or its just REALLY worn out, then a hone will make new crosshatches and the rings will be able to seat properly. a new bore will require a larger piston.