CBX250rs oil leak

**Icemaestro** · 30th January 2009, 00:36

Hey, my '83 cbx250rs has developed a little oil leak from the bottom of the right crankcase and also from around the oil filter bit - the gasket is clearly had it, so I called up econohonda, they don't have any... what should I do?Guy there suggested I try master gasket? What is this, do you think it would work, how to use it, and what to do about the leak from the bottom of the oil filter box...

Is the papery thing definatly a gasket? someone is trying to tell me there is no gasket for this?

Help is much appreciated, hopefully pictures will help :-P

**Icemaestro** · 30th January 2009, 08:15

bump......

**Max Preload** · 30th January 2009, 09:57

It's a gasket. If there are none available, make your own. Gasket paper is cheap enough. Just place the side cover on it, trace around it & cut it out. You could probably get away with just using an RTV silicone 'instant gasket' if you don't want the hassle of making one - just be sure to scrape and clean the faces thoroughly with a solvent that doesn't leave a residue like fuelite and apply the silicone sparingly - more is not better.

The small filter cover wil most likely not have a gasket as they usually have an o-ring due to frequent removal for filter changes. You can get a replacement o-ring from places like Seal House or Seal Imports.

**Icemaestro** · 1st March 2009, 23:19

Okay, so I drained the oil, removed the (extreemly) old gasket for the right crankcase, and replaced with master gasket and also replaced the o ring on the oil filter. put it all back together, put oil in....

the master gasket has fixed that oil leak, now it's just leaking from the bottom of the oil filter cover...what could that be? new o-ring, the bolts are tight...could too tight make it leak? should I try patch it up with master gasket? ;-) heh heh...

**vagrant** · 2nd March 2009, 09:50

Originally Posted by Icemaestro

Okay, so I drained the oil, removed the (extreemly) old gasket for the right crankcase, and replaced with master gasket and also replaced the o ring on the oil filter. put it all back together, put oil in....

the master gasket has fixed that oil leak, now it's just leaking from the bottom of the oil filter cover...what could that be? new o-ring, the bolts are tight...could too tight make it leak? should I try patch it up with master gasket? ;-) heh heh...

yes excessively tight bolts in aluminum covers can distort them and cause leaks.
In this case, I doubt that would be the cause. The filter cover plate looks to pretty solid.
Have you checked that the mating faces and sealing areas are smooth, flat and free from damage?
It only takes a little ding or scratch to for oil to weep its way out, especially from a pressurized area like a filter housing.
If it all looks good, then a little of the gasket goo would suffice as a backup to the O-ring.

**Max Preload** · 2nd March 2009, 09:55

What he said.

**Icemaestro** · 2nd March 2009, 11:42

Gah this would mean draining the oil again ay...wonder if i can get away with putting a bit on the outside (it's only leaking now when the bike runs - possibly expanding with the temperature?) The surfaces looked okay, but it is 25 years old, so I don't really know how they once looked :-P.

**Max Preload** · 2nd March 2009, 12:14

Originally Posted by Icemaestro

Gah this would mean draining the oil again ay...wonder if i can get away with putting a bit on the outside (it's only leaking now when the bike runs - possibly expanding with the temperature?) The surfaces looked okay, but it is 25 years old, so I don't really know how they once looked :-P.

No need to drain the oil. Just lean it over - even just being on the sidestand should be sufficient - you might lose 50mL. You don't even need to drain the oil to do a clutch.

The most likely reason it's leaking only when running is there's no oil pressure when it isn't running.

You say you replaced the o-ring. Is the new o-ring thick enough to be sitting proud of the groove?

**Icemaestro** · 2nd March 2009, 15:13

Huh, okay will try that in the next couple days. I vaguely remember that yes it was sitting off the groove? it was an original part, new one from econohonda.