1999 Fazer 600 surging power

[His Dudeness]

[quote author=His Dudeness link=topic=8716.msg87395#msg87395 date=1373664961]
[quote author=nick crisp link=topic=8716.msg87390#msg87390 date=1373662584]
Just read a couple of articles on this, interesting, but not sure conclusive in this case. One result of too much oil is that you wind up with bearings/crankshaft sitting in oil, creating excess drag, thus reducing performance. However, all those moving parts sitting directly in the oil churn it up and cause it to foam. This reduces lubricating quality, actually decreases oil pressure, with resulting carnage. Horror stories of broken con rods, holed cases, spark plugs blown out etc! Surprised nothing blew out of the breather pipe tho'.

Interesting stuff. I don't know enough about how the oil circulates to understand what happens when  too much is put in but I know you can wreck an engine with too much oil and I could see how you could have a drop in the power that it's putting out but you'd think it would effect the whole rpm range rather than between 8-10k or 4-6k. The circulation of oil is definitely something to look into though. An interesting area indeed!
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A shot in the dark: Perhaps at lower revs, the drag is too minimal to create a noticeable difference. As revs increase, (speed of moving parts) so does drag coefficient, so performance loss is more noticeable. If you check back on this thread, Fizzy Pies doesn't say anything about problems at low revs when his was overfilled. Littlejohnos bogged higher up the rev range. Fazerlads initial post said it bogged when he tried to accelerate hard. All fit in with this idea. Of course, it could be complete b*****ks!
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I don't know could be right could be a load of horse manure  :lol Are there any fluid mechanics experts on foc-u? :lol