jaguar
~SPONSOR~
OMG I'm blown away by my test results showing timing needs for best power can vary as much as 6 degrees depending on what type engine oil is being used. I first got a hint of this when I lighted different oils on fire and found the synthetic was the least combustible. Yes they are all derived from petroleum (as is gasoline) but the average number of carbon chains in the molecules increases on a scale from group 1 oil to group 5 oil. The higher # makes them lubricate better but less readily flamable (which is why synthetic oil makes more spooge).
So the logical conclusions are:
1) when you switch oil types (mineral, synthetic/mineral, synthetic, castor, castor blend) you need to recheck your timing. (FYI Yamalube is now fully mineral oil)
2) it's very possible that engines needing a quick burn would give more power with an engine oil that lowers the burn speed.
Factors in need of a quick burn fuel/oil mixture: high RPM, low squish velocity (typical on most stock bikes), excessive squish volume (typical on most stock bikes), high exhaust ports (large duration)
I guess I should tell some details of my tests. I have an air cooled 48cc engine and there's a long uphill road in my town and with my present gearing the bike slows down at the top section of the road to about 68% of top RPM. It has an adjustable CDI (my own design) and so each run I noted the RPM at one point on the uphill and the head temp after shutting the engine off. Gasoline is ethanol free.
Look at these two test results to see one engine oil is almost indifferent to timing changes whereas the other is very dependent on the timing.
The zero on the horizontal scale is just a selected point of timing as a reference point. It does not signify 0 degrees (TDC).
So the logical conclusions are:
1) when you switch oil types (mineral, synthetic/mineral, synthetic, castor, castor blend) you need to recheck your timing. (FYI Yamalube is now fully mineral oil)
2) it's very possible that engines needing a quick burn would give more power with an engine oil that lowers the burn speed.
Factors in need of a quick burn fuel/oil mixture: high RPM, low squish velocity (typical on most stock bikes), excessive squish volume (typical on most stock bikes), high exhaust ports (large duration)
I guess I should tell some details of my tests. I have an air cooled 48cc engine and there's a long uphill road in my town and with my present gearing the bike slows down at the top section of the road to about 68% of top RPM. It has an adjustable CDI (my own design) and so each run I noted the RPM at one point on the uphill and the head temp after shutting the engine off. Gasoline is ethanol free.
Look at these two test results to see one engine oil is almost indifferent to timing changes whereas the other is very dependent on the timing.
The zero on the horizontal scale is just a selected point of timing as a reference point. It does not signify 0 degrees (TDC).