Another oil leak diagnostic method

Patton suggested I post this here as well, so:

I'll add another oil leak diagnosis procedure, you might already know this, but others might find it useful.

This will work on most engines with a crankcase and a oil leak. The idea is to pressurize the crankcase with low air pressure, using compressed air, Regulated to 5psi, attach to the crankcase breather fitting, blocking all other external sources. On you bike there wouldn't be any but the breather where you now are pressurizing, but on other engines there would be a dipstick, PCV valve, etc. So with the crankcase now feed with air pressure regulated down to 5 psi, now you can see if it is a low leak, the oil coming out, or if a higher than oil level leak a spray bottle with soapy water will make bubbles at the leak just like a tire with a leak.
Remember to keep the Air pressure down to 5psi.


So some may have other ways as well. This method was shown to me by an Old Timer in the Industry many years ago, now thats become me, Old Timer.

thanx for the tip...makes alot of sense

best and easiest way is with the black light dye! that small kit from the auto parts stores or harbor frieght work great, stick in the small tube of dye,go for a ride then shine the black light around the motor. bingo leak found.

I used to use air pressure to test my RD400 crankcases. FYI to readers - one reason to limit the air pressure is so that you don't blow a crank seal. Maybe there are other reasons besides that.

spray footpowder works well... just clean off any oil on the outside of the engine, spray the white powder over the area suspected and take the bike for a ride...

that stuff wipes off easy (or washes off).

Jeff.Saunders wrote:

spray footpowder works well... just clean off any oil on the outside of the engine, spray the white powder over the area suspected and take the bike for a ride...that stuff wipes off easy (or washes off).

Can also just sit there looking around with a flashlight while the engine's running in neutral to see area where the powder starts turning dark.

Back in the olden days before florescent dye tracers, plain blue motor oil dye was added to the crankcase and watched for while engine was running.
Uncertain whether the plain dye is ever used anymore, or even available nowadays.

Good Fortune!

Jeff.Saunders wrote:

spray footpowder works well... just clean off any oil on the outside of the engine, spray the white powder over the area suspected and take the bike for a ride...

that stuff wipes off easy (or washes off).

Been using spray foot powder for years to find leaks. One problem with riding the bike is the wind blows the oil around.

First clean off any oil residue. Spray the suspected area. Block off the crankcase breather tube. Run the bike at 1500 RPM for a minute or two to pressurize the cases. Look for where the sprayed area turns brown. That's your leak point.