Just to let you know, Amsoil has out preformed Royal Purple for many years. It has out performed many Synthetic oils. Go to Royal Purples website, they offer no Test Results. Go to my website or Amsoil.com look at any of our products we show the test results,Amsoil uses a third party tester. The last i knew, Royal Purple hasnt even updated their oil rating. The only other Synthetic oil on the market that even comes close to out performing Amsoil is Mobile One, but they dont have other part of equation= their own filter. Amsoil offers a filter that filters out particials down below 5 microns.Our motorcycle oil is wet clutch compatible.Chech us out, bntsynthetics.com, Thank you
ZDDP is only reduced big time in oils with "energy conserving" in the logo on the back of the bottle. Any 40 or 50 will still have ZDDP. Weights like 20 and 30 will have far less of it...if any. It kills catalytic converters. If Amsoil is reccomended by Ducati for my 999 with Desmo valve train, i wouldn't hesitate to use it my XS650.
Or, if your that worried about needing higher levels you buy ZDDP plus and add it to the oil when you do a change.
still lots of ZDDP needed as there is 16 openers and closers on a 4v hammering the shit out of the oil. The lobes of the cam still hit rocker arms (except more of them) the same way the XS does. Minus a spring to pull the valve closed.
I'd imagine they still will chew up oil pretty good as they arent shim under like japanese bikes. Desmo was used because of poor valve spring construction back in the day. Technology is good enough that it really isn't even needed now. But they have gotten so good at it.
I've been using Chuck Norris spit. Gives me and extra 50hp and punches cell phone drivers.
I noticed your study was dated 2005
Reyclebill, where did you see 2005? Study looks to be from june 2009.
Hello ReycleBill, if you could give your filter number, i will cross the number and see what we offer for your filter. Im sure we have a filter that will work in your 83 xs. Thank you for your interest.As far as test results, Amsoil keeps up on Federal guide lines and laws.