According to my Honda manual: Do not use oils with graphite or molybdenum additives. They may adversely affect clutch operation.
Do not use "energy conserving" oils. They may adversely affect lubrication and clutch performance.:prof:
If I remember right Pr1malr8ge use the Rotella 15W-40, which you can buy at Sam's Club, 5 gallons for $55. Comes out to about $2.70 a quart, but he did say that he changes it more often. :noidea: Still cheaper in my opinion.

I know you all are talking 4stroke but I use Rotella 15w40 in my 2smoke and it has the wet clutch and I use it in my sons KLX110 and never had any problems out if. I change mine about every 4 rides. When I do it still looks like the day I put it in. Maybe I don't need change as often but for no more than it cost, I do anyway. I have it laying around all the time as this is what my diesel truck uses as well.
I have been running the Rotella 15W-40 for years now. This is what is known as a heavy duty diesel oil. They resist the viscosity breakdown that happens with 10W-40 automotive oils. With the new formulation that Shell went to about two years ago they actually went and got the JASO-MA wet clutch motorcycle certification.

The bottom line is that if you change it often enough even 10W-40 automotive oil is fine. Just stay away form the "energy conserving" labeled oils. Contrary to popular belief most "energy conserving" labeled oil does not have any damaging friction modifiers, but a few do. It's more about the viscosity. Even if an oil has friction modifiers it can't get the "energy conserving" label unless the hot viscosity is no more than 30.

The thing that attracted me to the Rotella was the price and the good reputation it has among motorcyclists. It's about $11/gal at WalMart.

I have found that different oils can have a big effect on transmission shifting. If your tranny is not working the way you would like give a different oil a try.
James is correct. I do use shell rotella T 15w40, as said it is a heavy-duty diesel oil. It contains no friction modifiers. Let me say this. I love this oil how ever I do not trust it or any oil for that fact to run more then 2 rides in my bike, any sand track it gets changed after that ride.. You will get others saying that motorcycle specific oil is a cheep insurance policy or peace of mind. Well, my wallet does not like the expsensive oils.. If I knew I was to be riding a full weekend 12+hrs in sand with no viable option to change my oil I might consider running the exspensive stuff. How ever this is not going to happen in my case even if I go to silver lake I can still return to my truck n trailer and do an oil change..

So in my opinion the price of shell R-T 15w40 and the fact that I am extreamly consience of changing oil this stuff is the best oil period. Been running them in all my bikes for the last 10yrs..

For those like DK from TT who go 5hrs or more on a bike before changing it maybe wiser to run the more expsensive stuff I how ever know people on TT run the shell Rotella T more then 5 hrs just fine. Me, nope not gonna try it..

To add I tried Mobile 1 once and I can say that my clutch slipped badly. Switching back to Shell and it was ubber good..

Now, The oil debate is just that.. You will undoubtly get someone who used shell and had a motor failure and blamed it on the oil. For this I am doubting it was due to fresh oil. More then likly it was not enough oil, or to old oil, or mechanical failure of the oil pump..

If you do use shell rotella T, I highly suggest changing it more often then you normaly do with the expsensive oil, even then the shell will still end up being cheaper..

To off set the cost even more I reuse the oil in my lawn mowers, pressure washer, & then it's burned to create heat..
another way to say this is not to use an oil with "friction modifiers", this is the slippery stuff like moly for instance. This stuff ruins your clutch plates.

I have been using car synth trans oil in my 2st gear boxes for a few years now. I use Rotella T synth in my 4st. I use the Rotella in my 2st if Im out of trans oil. I use the Rotella cuz its good, cheap at Walmart or Pep boys, use it in my diesel truck, etc, one oil for everything.

Since you like to change frequently I would use regular oil or a blend. BUT, my recommendation to you is to NOT change your oil so often and use a synth oil. Unless you suck water in from a creek or severly over heat the bike the oil will be fine.

I ride my KTm that has two filters and 2 screens for several rides before changing the oil. I change the filters every 2-3 oil changes and clean the screens when I change the filters. My 525 is at 8800mi and still doesnt use oil with this routine.