oil and spark plug questions

[FLRider]

I have a 2012 S8 150, and I've changed the oil twice on it myself.  I went to Walmart today so I can change it again since I've been running 5/30 full synthetic in it this last time.  I couldn't find 20/50 last time.

Today, I spent 10 minutes scanning the shelves for a single quart of 20/50 oil, and I COULDN'T FIND ANY.  I picked up 10/30 (the thickest available) since I wondered if oil was blowing on the spark plug when it first cranks up since it may get by the piston rings.  My mileage seemed to go down these last 2 weeks, so that's why I wondered.  I've only got about 2K miles on this oil presently.

I have not looked nor heard why 20/50 isn't available in WallyWorld, or if some major change happened in the industry.   Has something happened which I've not heard about?
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Also, I'm desiring to change my spark plug.  Months back I looked online, and local parts stores carry the plugs.  I have 8500 miles on it, and I got it at around 3500 miles.  But I've not paid $35 for a shop manual online, and I'm wondering if just a socket wrench and an extension will handle it.  So I have 2 questions.

1.  Where is the plug, and how do I safely get to it (without damaging the plastic covers)?
2.  If any of you have the PDF manual, could you copy the page(s) showing where it's at?  And if you know a site where I can find it myself, I'd be ok with that too. 


Thank you for the help! 

[Stig / Major Tom]

What oil does your owner's manual specify?

Stig

[FLRider]

Here it is.  10/30 works ok.  But most of the latter viscosities are in 40-50 weights, which would work better here in FL.

[Stig / Major Tom]

Yeah, looks like a 50 weight oil would be much better for Florida riding.
If walmart doesn't have any, best shop elsewhere.
Motorcycle shop or autoparts store....even expensive oil (AMSOIL) won't break the bank at less than a qt. per oil change, yes? AMSOIL can be ordered from their website.
Stig

[FLRider]

Thank you for your help Stig.  I used to use AMSOIL all the time on my motorcycles.  It's the best!  I'll have to find a local distributor (just re-read your post; I'll check their site).

Do you know anything about accessing the spark plug?