got a 1979 yz80 yamaha and i was riding out in the country stoped at a dudes house cause i was low on oil and i put 10w 40w motor oil and after a while it lost its power and the power band wouldnt even kick in. and another? it will not start now it just keeps back firing no starting tho ive cleand the carb piston head and exuast and still no fire just back firing ANY HELP WOULD BE APPRICIATED

 

so you put motor oil in a 2 stroke?

 

no ok this is how this thing works lol on the right side where the clutch plate is it says motor oil so i put it in there whene i did it it was running fine for a lil bit then it started to fill non powerish i tried to make the power band kick in but it wouldnt do it and whene its running right i cant stop the power band from kicking in but now it wont even fire it will just back fire thanks

 

OK for 1 slow down...

It will not fire but it back fires??? How is this???

Even if you put motor oil in where the 2 stroke oil goes it would fire... It may (will) stop the plug from firing but a new plug grounded out would fire...

Just clean everything out... Motor oil, fuel oil, new plug and so on... A 2 stroke will take a pounding and still run...

What you have told us sounds like more than 1 problem....

Just trying to help...

 

well i don't think i should affect it that much since you put it in with your gear oil. Your gear oil should be a sealed system how could you be running low? but anyway i don't know how to help you.

 

<div class="FTQUOTE"><begin quote>Originally posted by: joshjines

no ok this is how this thing works lol on the right side where the clutch plate is it says motor oil so i put it in there whene i did it it was running fine for a lil bit then it started to fill non powerish i tried to make the power band kick in but it wouldnt do it and whene its running right i cant stop the power band from kicking in but now it wont even fire it will just back fire thanks</end quote></div>

The bike is from 1979 what can you really expect. Has it ever been rebuilt?

 

I don't think the oil has anything to do with your problem. I think it was a coincedence the problem started when you put the oil in. I mean, if you screw up putting oil in a motor you just need to stay away from dirtbikes. It sounds to me like you have a busted reed valve. The reeds go between the carb and the engine, so my advice is to pull the carb off and check them first. This would cause your engine to do all of the wacky things it's doing.

 

hey quess thanks for all the help you have givin me a will back like 2 weeks ago i put motor oil wher it says motor oil and it ran fine all day then i take it to the shop to get kick start fixed and they just maide everything worse they broke part of the clutch but it still works halfway so i went in and fixed althat put some oil in fired her up she ran like a champ so i took her to the country and ran her good but it was almost impossible for the powerband to stop kicking in is that normal and i was riding back and she lost power out of the blue so i shut it off and it hasnt started since ive been trying every thing the yz has never had a board kit in its life but it has had new rings in piston a couple years ago and half that time it sat so i bought it and its been running good [DEPENDS ON HOW YOU RIDE IT] im just trying to get her going again and again thanks for all the help guys oh she gets bright white spark im told that is the best and the hottest thanks

 

yikes... talk about run on sentences...

anyways, it sounds like you're fouling plugs... mixture accurate? running rich?

 

Wow, how can you people even read his posts?

To fix your bike: Step one, learn how to use proper grammar and find someone with some mechanical ability. Step 2, clean the carburetor. Step three, check your reeds for any chips or cracks. Step 4, check the compression. Step 5, check for air leaks between the carb and the cylinder. Step 6, post the results in English so we can read it.