bearing skid

[Triumpy boy]

Years ago HD motor co prior to releasing there own synthetic oil, did exhaustive research on the problem of bearing skid in roller bearing engines. Essentially the issue was that being as ball and roller bearing require contact with their respective races to roll, synthetic oil was thought to slick allowing bearing rollers to skid eventually forming flat spots that hastened bearing failure. Although most of us use regular oil in our xs,es due to our wet clutches, has anyone seen or herd of this problem?

 

[XSLeo]

I don't think it happens. If the oil keep the parts apart enough to skid then that means the two metal surfaces are not in contact, If no contact how can there be wear?
I think they didn't want you using anyone else's oil in their bikes. So they claimed this as a reason not to use synth oils. At least until they came out with one. Just a marketing pitch.
Back years ago they wouldn't do warranty work on a bike if you didn't use H-D branded oil. It went to court and H-D lost, they now can not refuse the warranty because you used other oils.
The main reason I don't use a synth oil in my XS650's is cost. The cost can only be amortized by longer change intervals. I can run my Harley 5000 miles on Dino oil or 10000 miles on Synth.
With the frequent oil changes needed on the XS650 the cost for the synth oil is not worth it. Oil changes of 1500-2000 miles is recommended. This is because oil gets dirty from the clutch and crushed in the tranny. The filtration system used isn't capable of filtering out this dirt. In my 75 using Valvolene motorcycle 20w50 oil. I run to about 1200-1500 miles with out any oil loss. After that it starts to use oil. The crushing of the oil and the dirt lessen the oils ability to lube the internal parts and draw away the heat lessen, at the 1500 mile range it gets so bad the engine runs hotter and gets noisier, fuel mileage drops.
All these thing says I need to change the oil.
Have tried it. I only get a few hundred extra miles to an oil change. I buy the Synth oil for the Harley at $43 a gallon. that's $10.75. The Valvolene is $4.95 a quart. With only a 20-30 % increase in mileage per change for a 55% increase in cost is not very effective,
On the Harley it is pretty much a break even deal. I do like not doing the oil changes as often as well as the increase in fuel mileage and about 25* cooler engine temps.
Leo

 

[kevski]

It's the friction modifiers in the synthetic and modern oils oils that create the bearing skid and clutch slip, i had the clutch slip problem only last year, changed to a motorcycle specific oil, problem solved, bearing skid is not a new thing.