back on oils

You're in the same boat I am. I did a poor job using the Hylomar and I've got a leak in the crank case flange. Not bad, but when I went from SAE50 to 10W50 V-Twin, it got worse.

So what happens to our oil seals when we use the latest oils. I heard years ago that the modern full synthetic oils were devastating on our old oil seals.
Dereck

Modern oil...Simple, ...don't use them. Case leak? l go back to the Thicker oil, and nip up the case studs/pins, sill a slight weep ..carry a rag .providing it does'nt find its way onto the rear tyre..all will be OK. Or bite the bullet.

http://www.morrislubricants.co.uk/scrip ... tegory=114

I would think any rubberised seal that has been cooking inside the engine for even 10 years will be starting to go off, 20 + and they will be a ticking failure.

Im running Castrol 20-50 regular non synthetic oil.
The cases were sealed with a silk thread and Wellseal.
There is no room in the seal well for two seals. No room
for a standard double lip seal either.
The "bite the bullet" would be open the cases, shim the
crank to the DS and put in the double lip seal relying on
the steel frame of the seal to keep it steady and intact.

Hardly a high tech problem really.

My bike has all new seals in it.

anyone know where to get double lip seals? I have used Maney crankcase seals but they are single lip with a rubberized steel case.
mike

The real question is. Are the seals we buy now days suitable for full synthetic oil?
So
Would it be true then that any bike still running that hasn't been touched for 30+ years should not use the full synthetic oils?

past Peel used Wellseal and synthetic thread and never leaked out case seams but also had 11th clamp bolt behind the barrel area. She essentially only ran 20/50 Mobil One as it was the best wisdom at the time among vintage riders. Thermal dimension change with vibration and torque of engine shifting seam slightly are main thing that breaks the seal more than any solvent action or oil or gas. Then the blow by can leak out oil even with a hi end replumbed case evacuation. My Trixie was a will power tester this year as could fill sump with oil and stay dry and if staying below 70 and taking sweet time to get there, stayed dry too but to zoom up normally 50's or higher, what a mess. So bad I misses most the year taking apart and riding my SuVee.

oh yeah in Peel fround the synthetic thread melted and contracted leaving voids in the sealant so only use natural fiber kind which is hard to find.

All the hand wringing is hard to fathom, the crankshaft seal cost a little over $2 and the timing cover is easy to remove so replacing it is not a major undertaking.
Change the seal and get back to it in a decade or so.

Oil pump seal - $2.
Drive side seal $2+ (unless you want something fancy)
Contact breaker seal $2+
Maybe even replace the relief spring -$2