Gas in gearbox yt125

[jnollet]

Hey everyone I just registered and I am looking for some help with my 1983 125 trimoto. The old gearbox oil smelled like gas when I first got the trike. It had been sitting for about 5 years. Anyways, I drained the old oil and replaced it. This morning I went to start the trike and it smoked really bad. So, I shut it down after a couple of minutes and checked the gearbox oil again. Once again it smelled like gas, was a rust color and gearbox wasn't full of oil anymore(level had gone down). I can't figure it out.
On another note, does anyone know if you have to do any mods when you start pre mixing instead of using the old oil injection system. Thanks.

[MTS]

Motor is pooched, the crank seal is leaking, tear it down.

[jnollet]

What does pooched mean?

[Black86tri-z]

What does pooched mean?

i think he's trying to say it's tierd and of need of a rebuild

[YTM 225dx]

The reason why your oil smells like gas is cause the needle valve on your carb is leaking, which allows oil to seep through the piston and into the crankcase. I dont think that means you need a complete rebuild. Just replace your carbs needle valve and change your oil again. The reason it smoked a lot was cause your oil was thinned down by the gas allowing it to bypass your piston rings.

[Tri-Z Pilot]

He's got a two stroke, not a four, so even if gas did get by the rings it still has to go through the crankcase seal.
What is probably happening is you crankcase seal is bad, which will suck your trans fluid into the crank then push it through the transfer ports to be combusted (thus the heavy smoke). The gas smell is probably pressure going back out into your trans which in turns brings some fuel with it.
In all the seal is like 5 bucks, and a couple hours of work to replace, (not 100% sure how to go about it on a yt 125 though.

[hadar]

The crank housing should be sealed unlike a 4 stroke. In truth there is no way that gas can get to the transmission unless you have a bad crank seal or a cracked inside case.

Z pilot beat me to it.

[300rman]

Or the case gasket is leaking..........

[chadpchadp]

I know it has been awhile, but you ever figure out what this was. I just bought a 84 YT125 and it has the same issue. Starts right up but blows smoke/oil out the exhaust pipe. Thanks.

Hey everyone I just registered and I am looking for some help with my 1983 125 trimoto. The old gearbox oil smelled like gas when I first got the trike. It had been sitting for about 5 years. Anyways, I drained the old oil and replaced it. This morning I went to start the trike and it smoked really bad. So, I shut it down after a couple of minutes and checked the gearbox oil again. Once again it smelled like gas, was a rust color and gearbox wasn't full of oil anymore(level had gone down). I can't figure it out.
On another note, does anyone know if you have to do any mods when you start pre mixing instead of using the old oil injection system. Thanks.

[yamaha driver]

normal amount of smoke and oil coming out of the exhaust is fine since its a 2 stroke.

[chadpchadp]

The amount I have coming out is not normal, its spits all over my garage floor, I ended up putting an oil pan under the pipe? Also pulled the spark plug and it is literally drowning.

[El Camexican]

The amount I have coming out is not normal, its spits all over my garage floor, I ended up putting an oil pan under the pipe? Also pulled the spark plug and it is literally drowning.

You both need to rebuild your engines.

[dougspcs]

Chad, you do know what 'pooched' means right, or do we need to explain it too you also??

Hope you got it for a good price!!

[oscarmayer]

the pistons and crank seal are all worn as mentioned. rebuild time!!!
BTW, welcome to the world of 2-strokers

[chadpchadp]

Yes I am pretty sure I have a grasp of the meaning of "pooched", but thanks for the offer of explanation. I am fairly new to ATV mechanics but have been trying to learn a hobby I have been out of for 20+ years. The question at this point is how "pooched" this yt125 is, as I do not want to put too much $ into it. The compression seems good, tested tonight at about 120PSI. I am hoping it is just a crank seal issue that can be fixed and make this puppy usable again. The bike is in great shape, all original, and cost me $75 (including 2 new tires on the back, an extra seat/fenders/tank plastics, and a bunch of new bearings). My intent is to try and start tearing the R crank apart tomorrow in hopes of finding the issue. Thanks for the help.

Chad, you do know what 'pooched' means right, or do we need to explain it too you also??

Hope you got it for a good price!!