Just picked up a new-to-me 1994 Timberwolf 250, got a great deal on it. I'm looking to change the oil, the books recommend 10w30 Yamalube 4, but can't find that local. Wally World has a Valvoline ATV 10w40 conventional, I think the Amsoil dealer (he's pretty far) has a 10w40 synth. The Valvoline was saying that it's specially made for wet clutches, among other qualities - am I better off to use a specific ATV oil, or should any oil work? I'm in Pittsburgh, and it's about to get pretty doggone cold - is it safe to use the Valvoline 10w40 dino, or am I better off with an automotive synth? I'm a little worried that the 10w40 might be a little thick for the below-freezing temps, but I like the idea of the Valvoline ATV oil. I also realize that oil is oil, and as long as you keep it full, clean and changed, you're ahead of the game. But if I'm gonna buy it, I may as well get the best bang for the buck. I'm sure oil questions have already been beat to death on this forum, but I sure appreciate the advice, thanks in advance!

 

That is an air cooled engine so do your self a favor and use a synthetic oil, they are thinner in the cold and better protection in the summer heat. I use the Rotella (shell) 5w-40 full syn and is made for wet clutches and so does a lot of others use this for their machines. Amsoil is great oil but very pricey, the Rotella is not cheap but much less than the Amsoil. Keep that oil changed on a regular basis as the autoclutch uses the crankcase oil so it will get dirty fairly quick, but you need to keep that clutch debris out of the engine, so change at least once per year or 2x if you ride a lot.

 

Can't go wrong with the Rotella...whatever you choose, dino or synthetic, do yourself a favor and just change the oil often...clean oil will always protect better than any "whatever" dirty oil...

 

DirtDevil.....I agree with you 100% with one exception and that is high heat. In the summer months around here it can reach upper 90's to near 100 degrees and this is where syn oil shines. Being an air-cooled engine they have difficulty keeping cool in high heat whereas the syn oil can stand temps up to around 400 degrees and keep going, no dino oil can hold up under extreme high heat. If you live in an area that does not see high temps or you don't ride in high temps then the syn oil is no where near as important. As you said any clean oil is better than dirty oil in anybodys book! I have to say though for me my oil barely ever gets dirty before it gets changed even in my truck. I owned a bear tracker (wifes machine) for about 10 years, fun machine to ride and it got changed at least once per year with a new filter each time and never had an issue with it!!

 

Thanks for the advice, guys. Turns out my local cycle shop is a Yamaha dealer, he's got Yamalube 10w40 for 5 bucks a quart, I think I'll start out with it. Shouldn't need the full synth yet since it's winter, might try the Rotella in the summer. I work with small engines - mowers, tractors, etc. and use a lot of Rotella SAE30 dino and 15w40 diesel synth - good stuff.

 

Rotella T6 full synthetic will work better in the cold as well. Stays thinner than dino oil. My Arctic Cat 700 Diesel starts at -10F on that oil as easily as warm summer. Plus, Tractor Supply and Walmart sell it in gallon jugs cheap.

 

Gotta agree with Hydrex on that just use the rotella and be done. I use the 5w-40 all year round, better in cold and in heat. Your 10w-40 dino oil in the winter will be thicker for harder starting. I just bought a gallon jug of t-6 rotella for 24 bucks so it is only pennies more than your dino price.

 

I don't partake in "oil" debates because opinions tend to take a suto-religious point of view on the topic...all I will say is that Mobile 1 (the first mass produced publically available synthetic oil) didn't come out until the mid-'70s, meaning good'ol dino juice was more than getting the job done through 2 world wars and the muscle car era...not to mention there has been significant advancement in the dino stuff over the last 40 years...I've torn through enough motors to know that if you keep it clean you'll be fine, if you don't, you wont...

 

Whether it is 80 or 100, i dont think the engine runs more than 20 deg different. If the oil is 220 or 240, doesnt seem like that big of difference.

Maybe someone with an infrared temp sensor can check the cyl temps on a few diff days when the outside temp is different. 30 degrees vs 50 or more, 50 vs 70, 80, etc. would be interesting to see if operating temps vary in direct and equal proportion to air temps.

 

Mr Summit I can agree with you on a liquid cooled engine but this is an air cooled engine and on a hot summer day the oil can rise to critical temperature, for dino oil that is much lower than syn oil. I was also a small engine repair station for almost 20 yrs. Dino oil is fine for most applications, when it comes to extreme or hard use why not spend a few more dollars to be sure your engine has a better chance. Keeping the oil changed is a super big plus and for most it is all that is needed. If he is riding under extreme conditions and in high summer heat in an air cooled engine why not spend a couple extra dollars for some extra protection. I owned a praire 300 air cooled ATV for 16 years, it plowed my 300' long x 24' wide driveway every winter, also hauled wood and was used as a tractor on my property as well as ridden hard each summer on the trails. My oil cooler showed temps of 300 degrees on a number of occasions, dino oil would have caused engine failure but the full syn oil kept it in near perfect condition. When I sold it the compression was the same as when it was new. In the winter it started right up in -10 cold. Yep I am sold on syn oil considering the small increase in price to save an expensive engine rebuild.