Jump to content

Gas in the oil question

Recommended Posts

Ok guys, a little background: it's a 1992 dr250, kick start only, running a bst33 carb. It's a bit of a bitch to start and takes a lot of kicking. The jetting is all good (perfect colour on the colourtune kit).

Lately it got harder to start so I thought I'd check valve clearances again. I Pulled the small bung out of the left hand side to turn the engine to TDC and about 1.5 litres of thin, gassy smelling oil came out! 

I had cleaned and rebuilt the carb recently with a kit and installed new float needle, seat and o-rings so I Pulled it all apart again and checked everything. It all looked good though. I hooked the carb up to the tank on my bench and left the fuel on for an hour but had no leaks anywhere from the carb. 

When I dropped the remaining oil from the sump it was approx half a litre but it wasnt thin and it didnt smell of gas.

Can anyone explain to me what's going on??

Two main questions:

1

I always turn the fuel off when parked so how dud it get fuel in the oil? Could it somehow be getting in there while I'm kicking it over trying to start it?

2

How come the oil in the sump didn't seem to have mixed with the gassy oil that came out of the case?

 

Thanks - Jon

Share this post


Link to post
Share on other sites

since the volume that came out isn't much over capacity, could have been from carb flooding it even slightly.

kicking a lot can cause flooding.

what are you calling the sump? the oil tank in the frame? or the engine case?

Share this post


Link to post
Share on other sites

I got the other 0.5lt out of the 14mm sump bolt in the bottom of the engine just behind the sump guard. That's the drain point, right?

Share this post


Link to post
Share on other sites

I thought there was only supposed to be a small dribble from out of the side case bung (the hole you put the socket in to rotate the engine). I don't understand how so much came out of there but only half a litre came out of the sump. Surely it should have mostly drained to the bottom of the engine?

Share this post


Link to post
Share on other sites

Yeah it confused me because the volume of oil was only about 0.25 litre more than it should be so I can't understand why so much of it came out of the side. When I've had that bung out before I've only had a trickle of oil from there.  For that much oil to come out of the side I would have expected to see a total volume of gas/oil mix of around 3.5 litres

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×