cb350f PLEASE HELP

[dmonaghan]

So I picked up the head from the machine shop today. The guy was really good and went through everything.. took it right down to the bare bones, cleaned up all the valves.. pressure tested everything, put new seals in, lapped the valves and put it all back together. Also they honed the cylinder walls. I think that the original shop didnt hone the walls.. they were SMOOOTH as a baby's butt when i ran my finger on them... nice cross thatch now. Hopefully this will help solve the problem. Will let you know

 

[dmonaghan]

Got the bike back today.. after all that work... rehone.. valves all redone again with seals, guides., and lapped...

STILL SMOKING.. At first it seemed better.. hardly any smoke at all.. after about 20 miles it started getting a lot of smoke.. perhaps worse than before.

There is no loss of power.. if anything it drives better than it did before.. I can redline every gear. This time I was hard on it right from the start to try and seat the rings into the new hone.

Last time I was gentle and took it easy.. so this time I just mashed it.

Maybe I just need to put on some serious mileage? The bike had about 400 miles from the first rebuild when we ripped it all apart to check everything... rings looked perfect. Ive had mixed opinions on how long it takes to seat rings after a hone.. some say drive the shit out of it for 20 miles and you should be set... some people say drive it for 1000 miles before the smoke stops..

I had a different shop do the work this time... both places (and myself) are completely at a loss.. everything looks perfect so i dont understand where this oil is coming from.

Say im in 2nd gear... and I run it to red line and then let off and let the rpms drop down... as soon as i give it throttle again ill get a HUGE plume of blue white smoke out of the right side exhaust... and under rev or acceleration it seems to be a pretty steady amount. The left side has very very slight smoke and to me looks normal. The crank case vent still smokes when the bike gets warm also.

No idea guys.. even an idiot could look at this and see something is wrong.. but it just drives so so good... and perfect compression..

 

[Scooter trash]

Your exhaust pipe is full of oil, try it unhooked.

 

[Rogue]

Any update on this?

 

[hillsy]

Say im in 2nd gear... and I run it to red line and then let off and let the rpms drop down... as soon as i give it throttle again ill get a HUGE plume of blue white smoke out of the right side exhaust... and under rev or acceleration it seems to be a pretty steady amount. The left side has very very slight smoke and to me looks normal. The crank case vent still smokes when the bike gets warm also.

I kinda lost track of this thread.

Sounds like the oil rings aren't doing their job. Are they new? Correct size?

And what oil are you using to run it in? You should be using a plain old mineral oil - not synthetic or friction modified or anything else.