paphigliano said:We have found for stock bikes any oil in the primary will work some better than others, but if you are a big bore boy or a stroker nut ;that the synthetic gear oils,,,,,75/90 really make the clutch hook up. I have built 110hsp motors and used the stock clutch spring as long as you use the 75/90 in the primary,,,,,,if you use 10/40 or 20/50 in the primary on these style of motors you will need to upgrade the clutch spring,,,,,,its the way it works around here for us anyways.
That's quite interesting, I have deducted from reading these boards, that some guys are using Mobil1 75W/90W in their trannies, but this is the first time I've heard of it being used in the chain case/primary. Looks to me like the heavier gear oil will add life to a clutch period. What do you like in your tranny and crank case?
It would just be to damn easy for me to use Mobil1 15W/50W in the crankcase and Mobil1 75W/90W in both the primary and tranny.
I have been reading up on this quite a bit today, and being somewhat possessed by the need to understand oil, I study it quite a bit.
You being a engine builder/motor head, I'm sure you have read up a bit on this subject as well. I don't buy into HD's Recomendation of 20W/50W Syn for all three holes, Not in the best lubricant available for each application.
Thanks for sharing