Suzuki GSX650F Forum - www.GSX650F.biz

I'm a bit of an oil geek. Here is my take on it. Do not use anything that is energy saving, as already stated. It will cause issues with your clutch. The owners manual states to use 10W40 with and API classification of SF/SG or SH/SJ or a JASO classification of MA. The problem here is the API is about to release a new classification of SN. New classifications are supposed to be backwards compatible but vehicles requiring the older (way older) classifications are going to be SOL. The newer classifications are real good, but in the quest for better fuel economy, they are leaving out more and more anti wear additives. Newer engines can handle this, older ones, not so much. Now our engines don't have this issue so much, they are a new enough design to handle the new classifications without any fuss. I say all that to point out that the older classifications may no longer be found on a bottle of oil, and if you are on a quest to find SF or SG oil, you may not find any. The JASO calssification is the Japanese standard for oil wear resistance. Anything with that will be more than good enough.

Lets talk a little bit about the viscosity. The first number is the cold rating and doesn't really mean all that much, the number to be most concerned with is the second one, in this case 40. Try to stick with that. Todays xW40 oils are awesome, way better than they were just 10-15 years ago. I wouldn't go with anything higher, even in the warmer climates. 20W50 is an awesome oil for air cooled bikes, but our liquid cooled bikes do not require it, and you may see degredation in fuel economy because of it.

I have up to this point used Valvoline MC oil in 10W40. My next oil change will be Rotella T6 fully synthetic in 5W40. It meets all the API specs and JASO MA as well. It is also cheaper than the MC specific oils. The important thing here is that even the wrong oil (with the exception of energy conserving) is way better than not changing your oil. Don't feel compelled to change your oil as often as the manual states either once past your warranty. The best thing to do is send a sample of your used oil off for analysis, they can tell you if you can extend your oil change interval and the relative health of your engine. I usually run up to 6000 miles on my oil changes.

Hey bugeyed---OM calls for 15-50 in the over 100 degrees F---We get that here in So. Cal. and the desert---Ride safe, often and far-Luke

Yep, your right. I didn't pay attention to the chart since the verbage said 10W40. It also says that 10W40 is good past 104 F, I still think 50 is too much unless your burning oil, my .02 so take it for what its worth. There is quite a spread of viscosities that one could use, just pick your temp range and follow the OM and you'll be good. Like I said, it's hard to mess this up, just don't use energy conserving oils. Dino or synthetic is personal preference based mostly on how long you want to take an oil change. Dino oils are so good now that there really isn't any need to go synthetic unless you want to spend the extra money. Synthetics really show their true colors because they tolerate a long oil change interval, whereas dino oils are more than fine for a regular interval. There is no proof to conclusively say that running a synthetic is better for your engine on a normal interval, but they definately do last longer (stay in viscosity) on an extended interval. Of course you need to take into account for long idle times (adds fuel to oil) and dusty conditions (adds wear particles to oil). The later is why a normal paper air filter is actually better than a high flow filter (K&N and the like). That's a whole other discussion though.

castrol full syn MC 10/50

I think the reason I use the Mobil 1 15-50 is that the local Wal-Mart usually has it at a decent price.

Just put some Valvoline Motorcycle 10w-40 in my bike. First oil change and that oil filter put on in the factory was on there like a son of a bitch. Cut my hand up bad trying to get that sucker loose.

After a ton of reading I decided that the possible risks of running full synthetic for the first oil change outweighed any advantages of switching at 600 miles instead of 2000 or 3000. I ended up filling her with Shell Rotella T 15W-40. Been running fine in the 700 miles since the change. Going to switch to Amsoil Motorcycle Full Synthetic 10W-40 for the next change.

Rotella T6 fully synthetic 5W40