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post #9 of (permalink) Old 02-25-2008, 12:06 PM
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Join Date: Aug 2003
Location: Rome, GA
Posts: 659
Originally Posted by Vash View Post
I'm not worried about the price of oil as much as I worry about the price of a new clutch if I have to replace it. But chances are I wont, also I might have take it out and bathe it in some solvent.

So sure, I'll put my poor abused bike to one more expiriment. What oil is most likely to cause my clutch to slip? And how can we best determine how much the clutch is slipping?
My guess is some 5w20 with the starburst seal. It's going to be the thinnest at temp, right? I've never seen an energy conserving oil in a common motorcycle weight though. Most are 5w20, 5w30, and 10w30. My manual specifies 10-20w40-50. Will you see engine issues before clutch issues using a lighter-weight oil? Unless you find a starburst-seal oil in a weight you would actually use in your bike, it seems to be a moot point.

However, if you did carry out the test, I would recommend running the bike on a dyno with your usual oil to establish a rpm vs. speed baseline. Then change the oil and run the same routine to see if the rpm vs. speed differs anywhere. If the clutch is slipping you'll see a lower or erratic speed at any rpm where there is enough torque to overcome the clutch friction. Unless you're now working for an oil company trying to sell a new oil, it's probably not worth your time to even know.

"We didn't trade shoves; I did all the shoving." -Bobby Knight, 1981
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