Two cycle coming out of exhaust

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eagles22793

Member

May 25, 2008

146

0

• Aug 13, 2010

• #1

I have a 2000 yamaha yz125 and is jetted correctley but is still in the process of fine adjustment jetting. I mix the gas and two cycle 40:1. There is two cycle coming out of the exhaust every time I ride it. It almost seems it is running really rich but is not. The tip of the silencer has oil leaking out of it. Can any one tell me what this could be from?

 

slickpuss

Sponsoring Member

Jan 19, 2002

331

0

• Aug 14, 2010

• #2

It will happen to some extent on all 2 strokes. Your burning and passing oil through your bike. The engine is not going to absorb the all the oil, its not going to all burn up and you dont have some sort of catalytic converter to burn the rest. So dont be too upset by it.

 

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eagles22793

Member

May 25, 2008

146

0

• Aug 14, 2010

• Thread starter
• #3

I no there is going to be a little bit but i have owned many two strokes and never seen this much coming out of the silencer i am just wondering if this is a sign of something going bad or something that needs to be cleanded?

 

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Scotty99983

Member

Dec 5, 2009

44

0

• Aug 15, 2010

• #4

it could very well be your right hand main crank bearing starting to go.

has your bike been using alot of gearbox oil?

i know this is similar to what happened to my bike when the right hand crank seal went cos it sucks in your gearbox oil and fires it through the exhaust. (what a mess mine was to clean up) if its on the verge of going it wont suck in all of your gearbox oil it will gradually suck it in.

 

Patman

Pantless Wonder

LIFETIME SPONSOR

Dec 26, 1999

19,765

1

• Aug 15, 2010

• #5

How exactly do you know it is jetted correctly? Is your carb clean as a whistle inside? Does your choke operate corectly? What condition are the reeds in? What is the compression?

Get this http://www.eric-gorr.com/mxandoffroad.html and you will have a lot less headaches figuring out how things operate and what you need to do to fix them. Lot's or pretty pictures so don't worry about getting bored.

 

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eagles22793

Member

May 25, 2008

146

0

• Aug 15, 2010

• Thread starter
• #6

i am going to check the crank seals and bearings i am redoing the top end now do to a noise in the top end and found that the rings are worn out is there any way to check the crank bearings without spliting the cases?

 

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Scotty99983

Member

Dec 5, 2009

44

0

• Aug 15, 2010

• #7

eagles22793 said:

i am going to check the crank seals and bearings i am redoing the top end now do to a noise in the top end and found that the rings are worn out is there any way to check the crank bearings without spliting the cases?

Click to expand...

best way to check the bearings is to rotate your crank if they sound really rough and feel rough then they need done but if they are smooth and dont sound like they are grating or that then they should be ok.

to check the right hand seal pop the full clutch side cover off and look behind the gear that is on the end of the crank you should get a good enough look to see what its like.

 

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eagles22793

Member

May 25, 2008

146

0

• Aug 15, 2010

• Thread starter
• #8

the bearings sound great and dont sound gritty when in motion but on the seal what am i looking for were maybe some oil leaked out i have had the top end apart for a couple of weeks now but there is oil in the bottom end so if the gearbox oil leaks into the crannk area shouldnt it be in there by now or maybe it only dose it when the seal gets hot

 

F

FNG

Member

May 2, 2008

97

0

• Aug 15, 2010

• #9

All I know is my YZ 250 would spooge until I got the pilot correct. I had the main right, the needle and the bottom were still a little muddy for my taste which caused some spooge, though a lot less than when it had stock jetting in it.

I am running a 40 pilot down from the stock 48 and I am down to a 170 main from a stock 175 and I dropped the needle 1 clip. The spooge no longer drains down my silencer. Yes, I still do get wnough to wipe off but I am as close as I want it to be and still be safe.

 

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Scotty99983

Member

Dec 5, 2009

44

0

• Aug 16, 2010

• #10

eagles22793 said:

the bearings sound great and dont sound gritty when in motion but on the seal what am i looking for were maybe some oil leaked out i have had the top end apart for a couple of weeks now but there is oil in the bottom end so if the gearbox oil leaks into the crannk area shouldnt it be in there by now or maybe it only dose it when the seal gets hot

Click to expand...

you are basically looking for worn, split and cracked seals really. if there is a pool of oil in the bottom of the crankcase then your right crank seal is gone there shouldnt be a pool of oil in the bottom of the crank. as you say it may be when it heats up that its doing it due to maybe a crank or that in the seal expanding slightly and letting oil in.

another thing is is the smoke when running it kind of a white sort of dense smoke?

 

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eagles22793

Member

May 25, 2008

146

0

• Aug 16, 2010

• Thread starter
• #11

it dose smoke a little white but what 2 stroke dosent smoke so tht is hard to tell i am going to take the engine apart and look at the seals i will replace them just incase while i have it apart can i relace them without spliting the cases and taking the bearings out

 

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Scotty99983

Member

Dec 5, 2009

44

0

• Aug 16, 2010

• #12

if its smoking white then its burning your gear box oil, the way to replace seals without splittin case is to use screws and carefully screw 2 screws into the seal opposite each other and then pull the seals out using the 2 screws. but do it carefully you dont wanna screw them in too far and make sure to clean out any debris