1982 Tri Moto 125 2 Stroke oil in Trans?

[NatesTri125]

today after un winterizing my 125 I started it up and noticed that it was leaking 2 stroke oil pretty bad, I traced it back to the vent tube I think that comes from the trans case? anyways I pulled out the filler plug off the top and sure enough it was filled up all the way to the top with blue 2 stroke oil..any help on what the issue is?

[NatesTri125]

Might be crank case....not too sure it's right behind the oil pump right side.

[El Camexican]

That's weird. You have an injector oil tank on that thing right? Any change someone connected the tank hose to the crankcase vent nipple? I can't think of any other way for your crank case to fill up.

[barnett468]

hello;


if you want you can try the following.

remove the pump

clean out the hole

place an oil pan under the bike

make sure there is a bit of oil in the oil tank

let the pump hang there and check it periodically for leaking into the hole.


you can easily make a new gasket to mount it back onto the engine if needed or get one from the link below.

http://www.cmsnl.com/yamaha-yt125k-tri-moto-1983-1984_model8966/partslist/A-08.html#results

[NatesTri125]

im not sure what hole you are talking about I guess, I pulled the whole pump out and piece that runs into the crank case that drives the pump was soaked with 2 stroke oil, 191916 if # 15 Oil Seal were bad would that make it keep leaking into the crank case even when not running?

[honda3]

The yamaha 125 and 175 have oil in the crankcase. U fill it up right near the right rear tire. Tansy for the transmission. The oil tank in back is for the top end.

[NatesTri125]

I know there is suppose to be motor oil in the crank case. I am getting blue 2 stroke oil in the crank case.. I am getting blow by some how it is getting by the pump.

[NatesTri125]

also know any other part sites? I live in maine and the shipping on cmsln.com is 27. eur which is 37.27 usd. the parts are only 10 bucks.

[old-yellow]

its sounds like your the oil injection tank gravity leaked 2stroke oil through the oil injection pump and it leaked past seal #15 , never herd of that happen before I am wondering if there might be something wrong with the oil injection pump also or the shaft that drives it?

[honda3]

Hey Nate where in maine are you

[barnett468]

im not sure what hole you are talking about I guess, I pulled the whole pump out and piece that runs into the crank case that drives the pump was soaked with 2 stroke oil, 191916 if # 15 Oil Seal were bad would that make it keep leaking into the crank case even when not running?hi;

there is only one hole in the pump when you remove it.

yes it is the one the shaft runs into.

if you do my test it will likely determine if the pump is eaking but, ehere else is it gonna come from unless someone filled the trans while you weren't around, lol.

[NatesTri125]

When i pulled the pump off the shaft that runs threw crank case it was covered in 2 stroke oil if thats the whole you are talking about, which i wasn't sure if that was uncommon, i was thinking if the oil seal #15 was spinning and let it blow buy that might be filling the case? or the pump could also be bad i guess, but when i pulled the line off the carb from the oil pump before i took it off and it was still pumping oil into the carb. honda3 i am from the Augusta/Waterville area.

[NatesTri125]

i am about to order the gasket and the seals. Does anyone know if i should get a pump too? i guess the thing that bothers me is that the shaft that runs threw the case is covered in 2 stroke oil. isn't this a sealed pump?

[Burnt one]

i am about to order the gasket and the seals. Does anyone know if i should get a pump too? i guess the thing that bothers me is that the shaft that runs threw the case is covered in 2 stroke oil. isn't this a sealed pump?

Did you ever figure out the issue? I am having the same problem with my yt 175