As Al Gore says....."The Debate is over". Switched to Amsoil today... used 10w40. Also switched to amsoil gear lube... so all but gasoline...Iam full synthetic. Now for what I have learned.. FILTERS..... cut open a Fram,Purolator, Mobile one, and a super tech. The Fram is a piece of shit.....The Purolator is much better, I could not tell any difference in the $12.99 Mobile One and the $2.84 super Tech. I still have not experienced the difference in dino oil and amsoil, but you can bet I will use the Super Tech from now on. I do however think the Motor has less noise with Asoil, but I just changed it today and only have a few feet on the bike since the change. Amsoil says they are the ONLY truly synthetic motor oi onthe market. They say all others start with petrolieum... of course I am simply a lowely TV repair man and know nothing of such things. However I can troubleshoot, observe and analize..... that is what I do. I will report back with m data... and join the other umpteen million opinions for you guys to skip over....
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i just dumped the yahmalube that the shop put in after the recall(9 months ago) last weekend.went back to mobile 1 15-50 and there was a very noticable quietness to the upper end on my 1602cc.but with that being said i now can hear the dreaded headlight bezel rattle.oh well that will give me something to do in the morning.as far as oil/syn/real synthetic goes thats a personal call...to each there own... just go to http://www.bobistheoilguy.com/ and do some reading.spudwrench

I've run and repaired every damn machine you can dream of, from hummers to hybrids to steamrollers - you get the idea.

I've tested oils extensively, by taking identical 2.2l engines (you wouldn't believe how many of those you can find in great shape from a junkyard) putting em on stands, and running em for 10,000 approx miles. After the 10k miles I drained em assigned a number value based on grit and color, and then started the motors back up - dry.

To anyone who says "oil is oil, synthetic is a scam", there is truth to that. Under normal operating temps, the regular oil didn't come out that much darker than the synthetic did. BUT on every single dry test (oops I hit a curb and poked a hole in my pan) the synthetic oil ran at least twice as long as the conventional. Also, when you start to get into high heat situations (ran a pair with no coolant), the conventional seized up much sooner than the synthetic.

What does this mean to me? Well, if I can be sure that I'll never get it super hot, and never have a serious oil level issue - then yeah I'm wasting my money on synthetic. IF, however, you think that you might accidentally run her really hot, or you might develop a sneaky leak, then the synthetic just might be worth the extra 20 bucks per change.

BTW, I use amsoil in the R*, primarily for the amazing job it does do, at dampening engine noise. That thing is friggin LOUD when it's hot!