Correct oil for my XJ650?

Ive read that 20W-40 is the way to go but also that 20w-50 works as well. I just want to double-check.

My local Walmart carries Mobile 20W-50, will that work or should I go to AutoZone/O'Reillys/an auto parts store?

 

k-moe did a big write up on this which is pretty darn helpful: https://www.xjbikes.com/forums/threads/choosing-the-correct-oil-for-a-wet-clutch-motorcycle.43702/

Edit: Looks like we have the same bike/year. FWIW I use 15w40 without any issues.

If you're changing out the oil filter give my history a look. I just converted to a spin-on style and had quite the time getting the bolt off, seems to be a common problem.

 

20W40, 15W40, 20W50 are fine unless you live somewhere really, really cold all the time or really, really hot all the time. I've used 20W40 here in Michigan. What is MORE important is that you change the oil as required. I do mine every 1,500 miles with out fail. That is the reason I have the spin-on oil filter adapter. I've had my bike since 1985 and put on over 35,000 miles on it with 0 oil/clutch related problems.

D

 

This is a never ending debate. So many choices, so many variables. Read this thread, and you'll be closer to an answer:
https://www.xjbikes.com/forums/threads/choosing-the-correct-oil-for-a-wet-clutch-motorcycle.43702/

 

The viscocity should be matched to the average ambient air temperature during your riding season (chart added to the first post in the above thread) .
The certification should always be JASO MA, MA1, or MA2.