Topic: Smoke out of the crankcase breather (cb400f)

[Don R]

 I had a problem with stock jets that had been drilled once, that sucked.

[Polio]

I'm gonna clean them thoroughly and try to get the fuel level as close to the spec as possible.
I don't have a vacuum gauge so eventually I'll take the carbs to my mechanic for that.

I had a problem with stock jets that had been drilled once, that sucked.

my friends started joking about one of the previous owner haunting the bike.
maybe i should call a priest.

[Polio]

Well I installed the new jets today, massive difference.

I had to set the fuel level a couple of times to try and get it close as possible to the ideal setting,
but even if it's not perfect with the new jets the engine sounds much smoother.

I'm still hearing noises that shouldn't be there and the second pipe is only mildy warm to the touch even after a brief ride,
so I'll have to wait monday to get a new set of plugs to check how it's running,
but I'd say it's close to a full working condition.

[flybox1]

Great, now, you'll need to be sure the valves have been correctly adjusted, the timing and advance spot on, and then set the cam chain tensioner.
Only once those are complete, finish up with a vacuum sync of the carbs.  Its the icing on the cake.
Amazing how this quiets everything down.

[strynboen]

that smoking aut of the breather,,,can be gasoline mixed in the oil...it vill vauber aut vhen the oil gets hot.
.leaking kaburettors..can leak inside the engine..and the fuel sink dovn in the oil sump..and mix up in the oil..
so vait to the kaburetors Work perfekt,for some days...and then thange the oil...and take a long ride.
.and thek for blow aut then.
.underkompresion by leaking piston/rings is the other vay to make this smoke..

[Tim2005]

"the second pipe is only mildy warm to the touch even after a brief ride," ??  it should be way too hot to touch, the bike is not running properly on 4 cylinders.  That can cause the excessive smoke from a breather too.

As a quick fix/test swap the plugs between 3 and 2, if problem still persists on number 2 swap those two cylinders' plug leads around too. 

[flybox1]

"the second pipe is only mildy warm to the touch even after a brief ride," ??  it should be way too hot to touch, the bike is not running properly on 4 cylinders.  That can cause the excessive smoke from a breather too.

As a quick fix/test swap the plugs between 3 and 2, if problem still persists on number 2 swap those two cylinders' plug leads around too.

Vacuum sync is most likely off...not an ignition issue.
Needs all the other tuning points done, air screws set to plug color, and then a sync.

[Polio]

Vacuum sync is most likely off...not an ignition issue.

the bike is not running properly on 4 cylinders.  That can cause the excessive smoke from a breather too.

It was actually just the plug, it was still firing when I checked it, but maybe it was discharging somewhere else once mounted.
changing the plug solved that, besides it's not like I'll ever run out of fresh plugs now.

.leaking kaburettors..can leak inside the engine..and the fuel sink dovn in the oil sump..and mix up in the oil..
.underkompresion by leaking piston/rings is the other vay to make this smoke..

I'll bsure to check this, because there's stil a significant amount of smoke coming out.