Honda cg125-es(2007) blowing oil

[Guest]

Just finished replacing the output shaft in my cg125

Put it back together and started it up, but now oil is blowing out of the crankcase breather.

Initially thought gasses were getting past the piston and pressurising the crankcase, so I replaced the piston rings.

This made the engine run a lot better but it is still blowing out oil at an alarming rate.

Any help would be much appreciated

[eastanglianbiker]

have you over filled it with oil?if not have you connected the oil pump up correctly if you have had it apart

[Tango]

If you run it with the oil filler cap off and stick your thumb over the hole can you feel the pressure in the crankcase? Oil pump working OK and connected OK? Oil filter OK and not clogged?

[Guest]

Thanks for the suggestions,

turned out that I had been supplied an incorrect gasket, which was allowing oil straight from the pump channels into the breather splash guard.

It now runs without spraying oil everywhere, however it wont idle without the choke on. And if I rev it without the choke then it seems to burn a bit of oil.

Not 100% sure, but I was wondering if the idle could be because the petrol in the tank is about 1.5 years old, and the oil burn could be that the new piston rings haven't bedded yet?

[Tango]

Yeah.......I'd try fresh fuel and see if it's still burning oil once everything is bedded in.......

[Guest]

Slight problem with the bedding in though

Since it took so long to fix it no longer has insurance or MOT so I cant ride it around to bed them in.

But I also cant get an MOT since it chucks smoke out the back.

I don't suppose anyone knows a way round this.

[eastanglianbiker]

if its smoking out of the exhaust is it blue or white smoke as most bikes/cars white smoke when cold blue smoke means oil is getting into the cylinder and being burnt with the petrol/air mix meaning the piston rings might of failed or the valve seals have failed in the cylinder head

[acting_strange]

Did you scorte the bore before putting the piston and new rings back in?...because if not you may have given yourself a problem...

[Lumor_uk]

You can't usually get away with just replacing the piston rings. You have to get the cylinder head rebored. Which is what the guy above was trying to spell. The piston rings will now be bust as the cylinder will have scored them. Look for + 0.5 rings. Then you might need to rejet your carb. Easy option get a new bike or new cylinder head and rings.

[Guest]

The cylinder was fine, as was the piston, the rings were replaced because they were so full of gunk that they weren't pushing out any more.

[fredc]

You can't usually get away with just replacing the piston rings. You have to get the cylinder head rebored. Which is what the guy above was trying to spell. The piston rings will now be bust as the cylinder will have scored them. Look for + 0.5 rings. Then you might need to rejet your carb. Easy option get a new bike or new cylinder head and rings.

 

is this a wind up

[acting_strange]

You can't usually get away with just replacing the piston rings. You have to get the cylinder head rebored. Which is what the guy above was trying to spell. The piston rings will now be bust as the cylinder will have scored them. Look for + 0.5 rings. Then you might need to rejet your carb. Easy option get a new bike or new cylinder head and rings.

 

This isnt true Lumor.....you can just fit new rings depending on how worn the bore is....BUT...the bore should be scored first either using a honer or 1000 grit wet and dry soaked in parrafin (the way I was taught to do it as an apprentice motor engineer) ...

[Lumor_uk]

So he sands the bore finds he's not sanded it even or too much, puts the rings in, busts those too. Sounds like an awful waste of time. Taking the cylinder head off is no 5 minute job.