How do you find an oil leak?
 

As some of you will know, the Black Beast started to weep a little bit of oil into the belly pan at Cadwell yesterday. Have has a bloomin good look with a couple of halogen lights, but short of running it up to full chat in the workshop, can't for the life of me see where the oil is coming from.

I am also very aware how the airflow inside a race fairing can travel in all sorts of odd directions depostiing oil in the most unlikely places, so short of stripping the engine out and replacing all the seals, any one got a good tip here?

My next move is to have the oil cooler pressure tested.

I doubt it will be oil cooler itself. One thing I have first hand experience with, though, is that the fittings on both sides of the oil cooler hoses have a finite life time. If the ones on the engine block are aluminium, I'd suspect those first. Believe me, it's not much fun high-siding out of Park corner.

In which case I think I'll have that lot off tonight and get it checked out properly. Any idea where I can buy dye penetrant crack detection kits?

Oh How I bet you wish you were still in the RAF, Those kits were like free then....
Thanks for the set up help over the TD.
Glyn
PS messy but talc sticks very well to oil.....

if just in the bellypan John, it could poss be seeping from the clutch push rod hole, as the O rings do wear.

Just a thought to look at it & rule it out?

AK had this on one of our bikes and it took him a while to find it. When the oil cooler line went on Tango, AK found it quite swiftly......as it let go in spectacular fashion at Brands early this year:o

Finding oil leaks
 

Hi,
To find an oil leak first wash down the motor with GUNK or similar degreaser,then dry it off or leave to dry.
Then dust the motor all over (or in the suspect area) with Talcum powder,run the bike up or take it for a short run (in the dry) .Then inspect it again, then all should become clear.This works for seals,gasket faces and porous castings.A bit time consumeing but very cheap!

Steve

It must be obvious if you persist. Strip all the bodywork off. Clean everything up, run the bike up and turn the halogens on a nd hunt it down. It must be there. It is oil? is it ? not another fluid? ie coolant, brake fluid, clutch fluid, Fork oil. Talcum does work quite well. I would not strip components untill i had finally given up.
I would run the bike stationary on a paddock stand. road wind can mislead you.

My experince with car racing engines is that oil leaks can be the very devil to find because they usually only manifest themselves when the the engine is very hot, and the oil consequently is thin!

If it is a roadgoing bike I would run it hard to get it hot, clean it off and then set about it with talc/crack test developer on the paddock stand. Luckily the oil does retain its heat so you can do that and still have hot oil.

I have a leak on a Vauxhall racing engine at present, which I cannot find in the garage, but sure enough it re appears when used on the track!

Good luck!

Douglas

All of the above. I've looked hard for it, Nelly has looked hard for it, and no matter how hot I get the motor on the stand, it doesn't appear. I do have one problem in that as it's a race engine there is no fan on the rad, so have to resort to a large room fan to try to keep the water temp within limits whilst still trying to get the oil hot. If I take it on track, the airflow spreads the stuff all over the bottom of the engine, so it's hard to determine the source. Unfortunately it's not as obvious as it would appear!

I've only got one more day to do before the motor comes out for rebuild, but it's frustrating the heck of me at the moment.

Leaking Breather pipe or breather tank??

Ray.

In my experience the first place to look is the gearbox breather as mentioned by Ray - it's very common to leak from there.

I agree with MrR's advice - I have just located a mystery oil leak on my bike that had been bugging me for weeks.
It showed as a fine coat of oil mist on the rear brake pedal and around the RH clutch case, leading to drips off the crankcase centre joint.
I finally tracked it down with the talc method (after having taken off/resealed clutch case, oil cooler hoses etc) - there was a flaw in the clutch case just above the oil viewing window - I repaired it with araldite and ally foil and it's perfect now!

RX

You mention it being a race engine...ive seen these problems when they are up to temp, and under extreme load...cracks appearing in the crankcases...they only appear at high revs/heat/stresses.

Could also be a similar problem on the oil cooler...do you have any photos of the oily areas we could look at ?