Hi,

Searching online to see if I can solve a problem I have with my 1990 (I think, maybe it's a '91 or '92) 350 Big Bear 2-wheel drive.

Browsed through the forum, couldn't find a solution so I'm hoping someone may be able to help.

I seem to have either a gas or an oil leak that starts after the engine has been running for about 6 or 7 minutes.

At first I thought it was definitely a gas leak due to its location --- it's coming from the front, up under the gas tank from the left side and is leaking down onto the frame and on to the exhaust. It's not oil being sprayed out of the head --- the engine is clean. It's definitely coming from up by the upper left of the gas tank.

But today I put a can underneath to catch it and it appears to be oil --- not a gas and grease mixture.

When it comes out it is like having a tap just slightly on --- it's not a drip but it's not flowing fast.

And once it starts leaking the engine begins to run very rough.

I jacked it up, looked underneath and it _looks_ like it's coming from up the left side where the gas tank straddles the frame. There is a small piece of foam up in there --- maybe 6" long and 1 or 2" wide. I'm assuming it's protecting cables from hitting the frame?

The foam was soaked.

It sure doesn't look like there are any oil lines up there --- the cables look to be for the brakes and/or transmission.

Anyone have any ideas? And no, I'm not all that mechanically inclined. I'm thinking that I'll take off the front cowling of the 4-wheeler so I can get at the gas tank and if need be, take it off so I can see what's going on under it.

This image isn't my four wheeler but it shows the correct side --- the leak seems to be coming out of about where the "B" is in "Big".

Thanks for any help or insight anyone can give.

Todd

 

you say it appears to be oil. does it smell like oil?

 

Stupid answer but I don't have a great sense of smell. Tasted more like oil than gas and is definitely oil-like in colour (slightly dark).

However, I still do have to wonder if it's a grease/gas mixture. Perhaps there could be grease on some of the bolts up there and as it's draining down and hitting them and the frame, it's becoming a gas/grease concoction.

There's really no reason why there would be an oil hose up in that part of the machine, is there?

As far as I can see, there aren't any oil lines going up through that part of the frame for the oil-cooling.

Damn leak couldn't be in a more inconvenient location.

Thanks for the help. I know it's an odd problem and I'm probably not giving descriptions that are exactly easy to visualize.

 

Ok, I took everything apart...it's an oil leak!

Two tubes, one smaller than the other, were apart --- as seen in the pic below.

Question though: Does the smaller tube just sit inside the larger or should there be some sort of adapter that holds the two together? Or could I just put a gear clamp on them?

 

where is the tube coming from and where does it go?

 

Doing some more research it appears that both these hoses are breather/vent tubes.

One goes down to the brakes (it joins at a box and then the box splits off to each front wheel).

The other goes to the crank case and attaches close to the pull start.

Since I've had the 4-wheeler I've probably not put more than 25 km on it (it gets driven in the fall until the snow comes only about 100 yards a few times a week to trailer wood closer to the house). It's been a while since the oil has been changed --- maybe it's been doing this for a while.

The oil level appears to be fine. But I'm still going to drain the oil, replace it and then see what happens.

 

be sure to clean all your vent hoses.if they are clogged,they can't do the job.i had trouble with the one on the rear brake drum.i had to take it completely of the bike and bend and work the hose till i could blow compressed air through it. i then had to use a small drill bit to open the hole on the drum .i don't know about yours but my big bear has 4 vent hoses .crank case , final gear , differential and the rear brake drum .