Just for craps and giggles I threw 20w50 in the'02 to see if it made any difference in the smoke or shifting. Only put a few miles on it after the change, but I'm wondering if anyone else is running it.

I swear it felt like it added 10 hp at the wheel (J/K).

While I had the case open to change the filter my 5 year old decided to show my 2 year old what a dead leaf looks like when you crumble it in your hand and the wind blows it directly into my opened patient's belly 

I scared the dog when I yelled.

banjo

Oil, did anyone say oil? I'm a oil fanatic!!!  Anyways, I highly doubt that a thicker oil could make your motoring expience better in terms of performance, UNLESS you had some ring sealing problems and was loosing compression for some reason. Generally a lighter oil would produce resistance, but increase wear. Personally I use 20w50/15w50 on older engine (cars/motorcycles). What were you using before?

I'm so anal about oil and their effect on engines, performance and protection that I do oil analysis from time to time to analyze how well they are protecting the engine. I also keep tabs on my mpg.

Are you using synthetic?

On a bike I definately felt differences between synthetic and non-synthetic oils. My old ninja 600, I switched from 20w50 Castrol Dino to 15w50 Castrol Syntec and shifting in the morning was definately easier.

Actually oil wieght/viscosity has a very substantial effect on performance.  It's rather important, when trying to pull the most from your bike, to run a propper weight suited to your bike's ideal operating temperature.  That's in motors in general...bikes typically have a much more direct change in feel due by shifting.  I've actually seen an older GSXR 1100 dyno 3whp higher just by going from a 20-50 oil to a 10-40 (ambient temps were just too cold for the thick stuff).

I personally run 20-50 in my TL1000S and Yamaha Rat (both bikes have close to 30k) during the summer, and 10-50 during the winter.  This has maintains rather nice operating temps and made a noticeable change in shifting and accelleration in both.  My EX500 I run 10-40 all the time as she's still a very fresh block and isn't very tempermental to ambient temperatures.

suzuki brand 10-40. from all the threads i've read on here the last few years it doesnt really seem to matter too much what brand of oil. As long as there is enuff to hit the "F" mark.

-ash

I prefer Quaker State 4X4 Synthetic Blend 15w40, or Castrol Syntec Blend Truck and 4X4 15w40, whichever I can find on sale. I buy oil by the case, so I never have to go looking for the stuff just to do an oil change. I'm happy with the shifting...

  I run MOBIL 1 [ SYNTHETIC ] 15W50 in all of my bikes . The 05 GS 500 F runs cooler and shifts gears quite smoothly. Synthetic oil also gives you instant start up lubrication [ when most engine wear occours ] . You can also double your oil change intervals as compared to conventional oils. I have never had any problems at all .    CHEERS!