I'm curious as to what brand/weight oil you all are using in your ATVs.

I did my first oil change and tried Exxon 10w30 (or was it 10w40... can't remember now) and seem to be getting a little valvetrain noise after the engine warms up.

 

I haven't changed the oil yet, but I plan on using Castrol 'Act-evo' 10w40, with NAPA oil filter in my '05 KQ.

 

I use Suzuki brand oil, the weight that the bike calls for. Whatever brand you use there are two things you must consider.
1) It HAS (I cannot stress this enough) to be a motorcycle friendly oil. Many automotive oils are not wetclutch compatible, and therefore are not atv friendly. If you don't ahve a wetclutch on your bike then this doesn't apply. Some say just look for oils that aren't "energy-conserving" but non-energy-conserving oil gummed up the clutches on my streetbike so, take that for what it's worth.
2) It should be the recommended weight as called for by the manufacturer.
These are just my $0.02, and worth about as much.

 

I use 10W40 in whatever brand is on sale. My manual doesn't say anything about using "motorcycle" oil.

 

As long as it is not 'energy conserving', which is written on the bottom of a round label, usually on the back of the quart/gallon.

 

I run the 80W Belray Gearsaver.

 

... 20-50 wt synthetic "amsoil" summer... 0-40 wt fall & spring.. cooling fan rarely turns on..or you can use mobil 1 synthetic ...would never go back to dino oil again..been using synthetic's since 1977 in everything I own..including the lawnmowers and snoblowers...!!

 

I use Amsoil 10-40 4 stroke oil in my KTM, Belray Gear saver in my 2 strokes and valvoline 10-30 or 10-40 in the rest of my thumpers.

 

You want a motorcycle specific oil that is API SG/JASO MA. You said you used "Exon" oil. Was it car oil, or motorcycle oil? Best to NOT use car oil, and absolutely NEVER use "energy conserving" car oils (don't even use that crap in your car!). http://www.thumperfaq.com/oil.htm

I prefer Ester Synthetics. The synthetics have huge advantages over petroleum oils, and the esters have advantage over the PAO synthetics (like Mobil 1 and Amsoil). I run Maxima Ultra in my manual clutch sport bikes, and Maxima Extra in my autocluthc machines. http://www.maximausa.com/technical/l...beNews2002.pdf

I live in the relatively warm southwest, so I run a 40 weight (eg. 10W40) oil in winter, and a 50 weight (eg. 15W50) in summer. In the frozen north, one might want to run eg. 5W30 in winter, and 10W40 in summer.

 

I use Castrol 10W40 (winter) 20W50 (summer) they are not "energy conserving", and I have never had any clutch issues. A good freind of mine has a 2004 Z400 and he uses the same oil and he has never had a problem either. I change my oil more often (after every trip 10-15 hrs of riding, and the oil filter every other oil change)