Oil spit out breather?!

[dhoskins92]

Hello,
I just put a brand new Lifan 125cc engine in my pit bike. Started riding it today and it doesn't kick over as easily as the old engine did but it ran good once it did. All of a sudden it dies and spits a bunch of oil out the back of the engine out of the breather tube? wtf is that?! Engine is BRAND NEW not even an hour on it?
Any help is MUCH appreciated!

 

[my67xr]

welcome to Miniriders,

is the breather tube at the back of the engine new ?
if it has blocked up, or wasn't totally clear, or if it is kinked, it can restrict the crankcases' breathing capabilities, it can cause the oil spitting problem.

what process did you use to run the new engine in ?


don't forget to drop by into the Introduce Yourself thread to and say g'day

cheers, craig

 

[dhoskins92]

Yeah, the breather tube is new as well.
Im not sure what you mean by process?

 

[my67xr]

well, did you warm up the engine, and ride it for say 20 mins, only taking it to 3/4 throttle max.
then stop it and let it cool.
then take it out for about the same again, then let it cool
then maybe 1/2 hout to 3/4 hour, stop it, and let it cool.

doing it this way will help the piston and rings bed into the bore properly, and will give it a longer engine life etc.

you will also need to give it an oil change too,
to get rid of the thin/crappy original oil, and metal shavings etc in the bottom of the engine.

 

[my67xr]

the engine will most likely need to have the valves adjusted too.
when they are setup in china, the adjustments are too tight.
when it warms up a bit, the valves will expand, and not close properly, it can burn then out, and make starting it up warm, hard

here is a video explaining how to adjust your valve clearances,
set the intake to .003", and exhaust to .004", the engine will run a lot sweeter

[video=youtube;QJciyJRJh8Q]http://www.youtube.com/watch?v=QJciyJRJh8Q[/video]

 

[dhoskins92]

Yeah I would let it warm up and then ride it for like 5 minutes going through all the gears at low rpm then let it sit. I did that a few times then today i rode it in like 1st and second gear in the yard to do the same and thats what happened. So maybe change the oil?

 

[my67xr]

yeah i would change it out asap,
get some good 4t mineral oil (10W40), it will take around 700mls.
maybe do a 2nd oil change, after another hours riding after that.
it would be a good idea too, to take the r/h clutch cover off the engine, and check for any metal in the bottom of the case.
there is a filter screen towards the front/lower section that slides out too.
remove it and clean it up, then refit it all.
it should be good to go for a long time after that, with regular oil changes/maintenance etc


then you can decide if you want to use semi synthetic or full synthetic oil after that

it may have just had some foreign material sitting in the hose, and it blocked it
when the engine is running, there are pressure waves of air/oil inside from the piston moving up and down.
the oil will expand a little too when it gets warm,
maybe it just popped out the blockage that was there ?

it is not a constant spitting is it ?
and not a heap of smoke etc coming from the breather ?

 

[XXX-747]

welcome to miniriders bro
could ya of put too much oil in bud?

 

[dhoskins92]

Found the problem!
XXX-747 you win. When I got the engine it looked like there was oil in it but i couldnt really tell cuz it was SOOOO thin. It looked like the oil that the entire engine was douced in to preserve it so I added my own oil... which means there was too much lol
Thanks guys!

 

[Cordogs]

Running a bike in is a bit of a personal preference, some like to warm up run hard and use the engine brake (compression) to bed the rings, others take it easy.

What ever works for you mate, personally I dumped my original oil in the bin as soon as I got my bikes!

Treat yourself to a magnetic sump plug mate, it'll be your best friend and save lots of little nasties before they make it through for another cycle.

Also check out some of the other threads on bike maintenance, there might be a few things in there that you might not have known? Worth a look any how!

http://www.miniriders.com/tech-talk/37165-general-bike-maintenance-needs-tools-carby.html

And in further detail if you want, from a MR Legend!
http://www.miniriders.com/bike-setup/24239-achtung-noobs-your-new-pitbike-you-set-up-tips.html


Welcome to MR too mate!

 

[rotn50]

Running in mmmmmm, run it in hard hard hard. I kinda go stooopid when running in but in saying that I will let it rest after half hour for around 45 mins for the first tank, when these donks get hot you can smell the oil and hear the engine internals a lot more, a good sign of running a bike way to hot is the oil boils and comes out the breather, kinda like doing a 4th gear skid on a new tyre and popping it, ive been guilty of this on a few occasions lol.