Is this normal

seth martin

Member
Joined
Feb 17, 2008
Messages
45
i have a 33cc two stroke and i havve noticed what looks to be oil comming out near the exhaust is this normal? and if so how come its just oil when i mix it with the gas?
 


G

gone_fishin

Guest
more detail please, in the title and the post. remember you're a co-author of this repair manual...some other new guy may need to find this someday.

that's not a personal dig, it's merely a lesson in forum-usage :)
 
M

mickey

Guest
Some oil remains unburnt in a 2 stroke and condenses in the exhaust. Is there a lot of oil in the muffler? Isn't your bike brand new? Are you running an oil rich break-in mix? What does the spark plug look like? Oily?
 

seth martin

Member
Joined
Feb 17, 2008
Messages
45
its 25:1 it was in the manual to break in and run it on 25:1....its not a whole lot but enough that i notice and yes its new but i ride it alot...the oil i put in is blue and when it comes out its grey/black..im guessin this is the carbon?...the spark plug has a small amount of brown residue on it kinda on the threads...i just need to know cuz i have 2 more weeks onm the warranty and dont know if i shpuld send bacjk....
 

loquin

Active Member
Joined
Jan 11, 2008
Messages
2,210
as mickey indicates depending on the engine make, between 5% and 30% of the fuel goes straight through a 2-stroke engine without being burnt.

Some of the oil will condense in the muffler, as it cools down.

Oil molecules are larger and heavier than gasoline molecules, and so, they will condense at higher temps, and will not easily evaporate, as the gasoline will. (This difference in condensation temperatures is how the oil companies separate crude oil into it's components in a distillation tower at the refinery.) In your case, the oil condenses out in the muffler, while the gasoline goes on through.

A small amount of oil is normal.

The reason that it is black is because of the carbon. The dye, which caused it to be blue, was probably burnt & broken into carbon also.
 

seth martin

Member
Joined
Feb 17, 2008
Messages
45
ok i thought it was normal weedeaters and such are always oily so i figured this should be to would cuttin it down to like 4 ounces a gal help instead of 5 or should i stick to what it says
 

seth martin

Member
Joined
Feb 17, 2008
Messages
45
ok will do i put some stong work shop rags folded them up and put uner the rack and the motor where the oil seems to go to absorb it the rags touch nothing hot or moving
 
A

andyinchville1

Guest
One of my HT engines will drip from the exhaust and one doesn't....I asked Duane at Dax what might be the cause and he suggested that my float may be hanging up and letting a minute amount of fuel through the engine when it is off....I disassembled the carb to make sure the float moves freely.....now no more problems!....(when it was a problem I used to put a tin can under the exhaust to catch the drips....not a lot granted but enough to make a little mess over time....If your carb doesn't have a sticky float I would guess the above posts would likely be the answer to your problems.
Andrew
 

loquin

Active Member
Joined
Jan 11, 2008
Messages
2,210
I would guess that it would depend somewhat on driving habits, too. If you take the bike on a lot of short trips, the exhaust may rarely get hot enough for long enough to burn out all the residual oil.
 
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