What have folks experiences with SAE vs Synth oils been like with these machines?
Speaking of Trans and the front and rear differentials.

I know my engine really likes the Castrol Power 4T stuff.
Getting ready to do a complete change on the gear cases and transmission though.

[2015 Z Force 800 53/Trail EPS]

I too use the Castrol Power 4T or RS when I can find it...and its been the best. When mine was new I broke in the diff and gear case with conventional valvoline gear lube then switch both to synthetic. I then...in a short time.. developed a problem with the rear in that it was grinding the case somewhere as it was getting lots of aluminum flakes in the oil. Looked like automotive metallic paint. Because I had to change it a lot I switched it back to conventional and a 90w140 which slowed the grinding process. It wasn't the synthetic that did it and I still run it in the front..and its been great. Probably next winter I'll be pulling the rear gear case out and see what up. Think I know from someone else that was having the same thing. Anyway, if they are broke in, go to synthetic. I use a 75w80..or 90 in the front.

[I too use the Castrol Power 4T or RS when I can find it...and its been the best.]

I too use the Castrol Power 4T or RS when I can find it...and its been the best.

Im not saying your wrong or questioning your judgment, I was just wondering what your reasoning is on why its the best. I too am running the Castrol Power1 10w40 full synthetic in my 800EX this season. Its been one one two day trip so far in pretty high heat and dust in a low and slow environment. Temps seem the same, oil pressure light goes out on startup the same, engine noise is possible a little loader but it could be in my head. The only definitive improvement Ive seen first hand is that my fuel economy is better than it has been and also better than others in my group. I rode all day in the heat on technical trails in low with higher than usual RPM and used aright at a half tank. Everyone else was lower on fuel.

To the original posters question, you cant go wrong using a fluid that meets the manufacturers specifications. Im using the Castrol only because I wanted to try it and I was able to order it from Walmart.com with free shipping. Probably wont use it again unless its a deal or something stands out this year showing me its worth it. I have a few machines that I spread the riding out on so I figured that I put about 25 hours a year on each one give or take. So Im ok with just servicing them each once a year. Ive had no problem with  Valvoline ATV 10w40 or Maxima Premium 10w40. Both are cheaper and seem to work just fine for my use. I use 80w90 conventional gear lube for the differentials. Ive used Valvoline and Lucas. Cant tell a difference. Also drain those once a year so its overkill on maintenance.

As for your trans if you have a separate one, Cfmoto specs a 75w90 which is only available in synthetic which tells me they want a synthetic in there. They still call for 80w90 in the diffs of those machines so the trans must need synthetic.

NMKawierider gets the moneys with out of his oil by using it multiple seasons. Im more a fan of meets the spec and change it often. To each his own. Just try one out and if you dont like the results pick a different one for the next change. Im considering doing a fill to spill on my next change of the diffs. So far in my 2 services o. Them all Ive gone with the manual fill capacity.

Well, when I went to do its post break in oil change on my bush bike I went with the dealers suggestion because maxima is quite a bit spendy.
They did a good job prepping my bike and have answered any questions Ive had sraight up with no bashing around in the bushes.
I stay pretty tight with the maintenance schedules and keeping the engine adjusted but I noticed immediately a much smoother sound and feel with my engine with the Castrol Power.
The engine had already worn in and meshed together but everything just became crisper running.
Just because I want to KNOW I ran the machine out to 70mph and it was smooth across the entire range. It wasnt just smooth, it was relatively quick as well.
Were surface road legal here and once inawhile some idiot likes to tailgate. I like to Know what I have to get out of their way if I need to.

Because I use it as a workhorse as well and I live on a fair decent hillside moving dirt, planting materials, tending beehives and skidding fence poles and some actual timber around my place I'm going to lean towards maybe a bit overkill on maintenance and inspection. I don't bash it around and use applied leverage and blocks when I need to rather than slamming and jerking stuff around but I do use the machine so I pay close attention to it. Its not so much about preference but whats good for my machine.

 
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