Topic: Help pinpointing a leak

[normalguy]

My cb400f has a leak that is either a blown head gasket on cylinder 4, is coming from the plug, or is coming from one of the chrome head bolts.  The oil gunk is as high as the plug hole, which makes me think it's leaky higher up at the head bolt.  The temp on all headers is good, so maybe we can rule out the cylinder spewing oil past the plug hole.

My question: what can I use to clean the aluminum so I can see exactly where it's coming from?  A search of the greenspun board turned up a thread where someone used aerosol brake cleaner, but I'm pretty sure that would corrode.  Any ideas?

[eldar]

You can use any mild degreaser such as simple green. Just do not dilute it. You may need a bristle brush to help break up the oil.

[TwoTired]

Mineral spirits. (yes, the paint thinner type)  Works really well to cut oil and grime.  Brush or spray on, hose off.  I use it in my parts washer, as well.

Use thought about waste disposal, whatever is used for a solvent.
Cheers,

[normalguy]

Thanks for the advice.  I'll just get in there with the degreaser and a hose tonight.  If it ends up being the sealing bolts (#5 in the attached service manual pic), is that just an aluminum crush washer?  Is that a spot that would generally leak oil?