|Subject:||RE: OIL||Date:||Sat May 17 15:22:09 2014|
Ford v. Chevy, Redskins v. Cowboys - nothing gets quite so personal as choice of oil.
Your owner's manual says to use Valvoline Heavy (summer) and Valvoline Medium (winter). If not available, use SAE 50 and SAE 40.
ZDDP wasn't invented until the late 1930's, but it has been used ever since. ZDDP is particularly good to prevent wear on flat tappet camshafts. Unfortunately, the amount in motor oils is being reduced year by year.
Friction modifiers are a more recent invention. These reduce friction in engines to promote fuel economy and engine longevity. However, friction modifiers are NOT good for wet clutches.
Since Hendersons use the same oil for engine, transmission and clutch, we need an oil is has good ZDDP content, but contains little or no friction modifiers.
Most diesel oils, like Rotella, meet these requirements, but the hot rating (the 40 of the 15W-40) is a little light for summer use. My riding buddies complained that I was blowing a lot of smoke when I used that. Other folks seem to use it with with no problems.
Multi-viscosity oils were not invented until 1954. A good 20W-50 should be just fine instead of a straight 50, provided it has ZDDP and no friction modifiers.
Valvoline VR-1 Racing Oil comes in 20W-50, 40, 50, and 60. But read the label:
* High zinc/phosphorus provides extreme wear protection,
including flat tappet applications
* Additional friction modfiers to help deliver maximum
I know some people use this, and I haven't heard any reports of slipping clutches, so maybe it's OK.
What I use is Kendall GT-1 High Performance Motor Oil with Liquid Titanium (conventional dinosaur oil). It's got good ZDDP content, and no friction modifiers. My riding buddies don't complain, and my clutch doesn't slip. Kendall 20W-50 seems pretty good too, and has more ZDDP than their SAE 50. With your cold Vermont winters, that may be a good choice for you.
I went to the websites for many brands of oil, and compared their Product Data Sheets (you'll have to hunt around a little to find them). These usually give you the Zinc and Phosphate numbers, and they usually tell you about friction modifiers. I also called the tech support lines, and talked to them - some were very helpful, some were not.
So do the research, and guess your best. But the offerings, and the formulations change pretty quickly these days, so research early and often!