Hello, everybody

I few miles back I discovered an oil leak on my `96 GS500 with over 40k miles. After cleaning the area and waiting for the leak again I was able to pinpoint for the most part where it was coming from.

Ignore most markings in this picture, I got this picture from somewhere else on the internet. The black circle marked "oil drop" is where the oil is coming from.


Anyways, considering that I'm not mechanically inclined I asked around a few friends on what can be causing this leak and I was suggested that the leak was the cause of a bad gasket--especially considering how used this bike was.

Going on, I ordered up the new gasket and started to disassemble the bike. Once I go it broken up I noticed that the gasket was not visibly broken, cracked, or otherwise gave me (an uneducated person regarding such things) the impression that the gasket was at fault. There was indeed some oil on the lower part of the gasket which probably shouldn't be (or maybe it should?) so that might be where the oil was coming from. In the area where all the gears and other stuff was at there was a very small puddle of oil as well while the rest was clean. I did end up breaking the gasket when inspecting it so I will have to replace it but I have some questions regarding all this.


Now my questions are:

1) Should the gasket be visibly worn out, cracked, broken, etc, for it to be the cause of this oil leak or can it still be the problem while it looks good (to someone that doesn't know)?

2) Should there be an oil puddle where I described or is that another problem? If so, what can be the cause and how can it be prevented?

3) When placing in the new gasket, do I need anything else to keep things together or is it just a simple matter of align things and screw things on?

4) After taking off the crankcase cover I noticed that some screws were of different lengths after the fact that I accidentally kicked the place where they were and got them all mixed up. How can I know which ones go where again?

5) If this gasket was fine in the first place, what else could be the cause of this oil leak?



Thanks.

Yes, gaskets can look brand new and leak, I would make sure to very lightly sand all the mating surfaces and use a super thin but completely solid (no breaks in the bead) layer of red RTV to seal it all up. I did that on mine and not a bit of oil leaked since.

Oil is designed to get into every nick and cranny of an engine. Try wetting then end of a butter knife with oil, then trying to hold the oiled part with just two fingers. Kind of a tricky thing to do.

Yes, even if it looks find, oil can and will find its way underneath gaskets. That's what it was designed to do in engines.

An interesting thing to note, when you oil your chain and ride, all the lubricant can find it's way underneath the sprocket cover creating an illusion of an oil leak. I do not think that is the case for you though, just something to remember.

Thanks for the replies guys. They were helpful and I have done the gasket change and there appears to be no leaks after a ride.

Definitely good to know that gaskets can still be the cause of an oil leak even when they look new. Funny how I imagined seeing a gasket with a big chunk of it missing or completely cracked 

A gasket that looks good can leak. Might have been as simple as a loose bolt which allowed Some oil by. After the bolt has been retightened the oil still goes along the same path as when loose. Gasket change time.