Oil spitting exhaust

[mustangfury]

I have a 1993 kx 125.

Every time i ride i have (what i believe is burnt) black oil that spits out of the end of the silencer and the joint between the front fat part of the exhaust and the pipe that goes to the silencer.  Is this normal?  I need to repack the silencer and just wanted to fix the problem if there is one before i repack it.

Thanks.

Another thing:  I had a spark plug recently oil foul.  The top of the piston had a thin even carbon coating.  Is this normal as well or is there something i should do to correct it.  the plug had been running for about 15 hours.  It was the plug that i got with the bike and was not the recomended plug for it NGK BR10EG.  I have the right one NGK R6254k105.  I don't know if that makes a difference.  The BR10EG is a cheaper plug and i didn't know if that could be why it fouled thanks again.

[alan]

What is your oil mixture ratio? I think I would be tempted to try a hotter plug like at least a 9 instead of a 10 is really a cold plug. 

[mustangfury]

Will i get better performance out of a hotter plug?...  Such as better throttle responce or what?...  Is the NGK R6254k105 recomended by the manual a hotter plug then the 10 and how does it compare to the nine?... Will a hotter plug burn off more of the excess oil? <------- is that what will stop the oil spitting?

Thanks.

[alan]

I was making the hotter plug recommendation  based on one of my  2 strokes books. The 10 is the recommended plug for your bike. First you really need to see if you have the correct jetting and oil mixture for the bike. Plug fowling can also be from riding style  and gearing, bogging it down in to high of gear. However oil fowling is usually associated with other problems.

Alan

[gowen]

Could have a crank seal leak.

[Hillclimb#42]

 Check the new plug after riding in normal conditions. Should be brown, not black. I suggest checking floats in carb.
Another important thing is what ratio and what 2-stroke oil? Is it smoking alot? Does it smell good or like burnt plastic? when the bottom end is ready for seals, it often sucks crankcase oil into cylinder. Tell-tale sign of this is constant smoke, that stinks. They all have some drippage, but when its obviously getting worse and worse something is up. If the motor is pretty fresh, then it may be too rich for any number of reasons. Jetting, mixture screw adjustment, float height, ratio, riding style, worn seals, even a clogged air filter can cause a rich condition. I'm sure I'm leaving out things too. Needle adjustment also makes a big performance difference.
 I am not the plug wiz. I always run the B8ES NGK. I am not sure what happens by going one step hotter or colder.
Keep tweaking till you get the brown plug, then repack silencer, if needed. Good Luck! Keep us posted of your findings.

[mustangfury]

I run between a 32:1 and 40:1 fuel:oil mixture.  It has a little blue smoke coming out of the silencer when i first start it, but the smoke goes away once it warms up.  I was teaching a friend of mine how to ride because he is always talking about how he wants to get a like 1000cc honda street bike and my friend and i keep telling him that he doesn't really know how much power that really is.  I took him out on my little 2stroke Kawi to let him see what kind of power bikes really do have. Anyway, he wasn't really winding it out and was bogging it a little, so that could have been why the plug fouled.  Oh yeah, I use honda race oil 32:1 for 2 stroke engines.  And it doesn't smell bad.  The Oil spitting out hasn't gotten any worse. I just haven't had the bike long enough to know what is normal.

Thanks.  Very appreciative of all the help.

[mustangfury]

I repacked the silencer and haven't had the oil spitting problem.  If the silencer gets too old and too full of oil, will that cause a dripping/spitting problem?  The silencer packing was pretty saturated.

Thanks.

[FactoryPhil]

Yes, that is exactly why 2 stroke silencers need periodic repacking.

[Hillclimb#42]

 Yeah, definately. If you putt around for an easy ride then rip it hard later, it will smoke like its on fire, even if it you have already killed the motor. The same thing happens after several hours of riding. It gets enough 2-stroke oil in it over time to coat the packing. Then you ride it hard enough to fry eggs on the silencer. That makes sense to get the smoke goin. 

[mustangfury]

Thanks for the help guys.

Could have a crank seal leak.

He said it could have been a crank seal leak.  Now that everything is good with the bike I'm pretty sure that isn't what it is but i was wondering if that had been the case would it hurt a bike to run it with crank oil leaking into the cylinder.

Thanks again.