Question for gearheads

[Relic]

I have a late 97 Buell here with oiling problems. I can't seem to put my finger on the problem. The problem is it blows oil out of the engine above 5500 rpm. Anywhere in the rpm range below that it works just fine, good oil pressure. But once she gets hot and running at high revs it blows oil out the breather. I was thinking the excessive pressure was blowing it past the butterfly valves, so I installed new ones with the same result. Any ideas out there?

[Wide]

Too much oil ?

Butterfly valves suck, try some positive crank ventilation, if your getting blowby possibly you have a clogged vent somewhere

[Relic]

Too much oil ?

Butterfly valves suck, try some positive crank ventilation, if your getting blowby possibly you have a clogged vent somewhere

Not too much oil, I thought of that.
Clogged vent? Why would it only blow out at high revs?

I did install jets to squirt oil under the pistons like a Twinkie has.

Maybe at high revs the pump can't handle the jets.

[junior]

hey bud-

the usual trick is to start by running it a half quart below normal. however, even that isn't a certain thing. nice mod installing the jets, but you might be onto something. the scavenge cycle on the stock pump is designed to accomodate a set volume of oil generated by a non-jet equipped engine. although we are talking about a minimal amount of added volume at high revs it might be enogh that the pump cannot evacuate the crankcase completely at wfo and the remainder finds it's way out through the breather. maybe a simple mod might be to drill out the holes in the breather bolts to relive some of the pressure and keep the oil in the case.

let us know-

j

[Relic]

hey bud-

the usual trick is to start by running it a half quart below normal. however, even that isn't a certain thing. nice mod installing the jets, but you might be onto something. the scavenge cycle on the stock pump is designed to accomodate a set volume of oil generated by a non-jet equipped engine. although we are talking about a minimal amount of added volume at high revs it might be enogh that the pump cannot evacuate the crankcase completely at wfo and the remainder finds it's way out through the breather. maybe a simple mod might be to drill out the holes in the breather bolts to relive some of the pressure and keep the oil in the case.

let us know-

j

Yeah! I thought of that too. Drilling out the breather bolts worked on my twinkie, but on this Buell it has no effect.
Keep tossing the ideas, dude. We may just figure this out yet.

[blkfalc4]

Motor sumping?
Have you done a leakdown? Poor ring seat will cause excessive blowby.