I like the re-refined oil since it's been refined twice...

 

Mobile 1, full synthetic. The bottle with the gold cap. Yes it is "Car" oil. But it does work well with a wet clutch. Used it for years one my WR426 and never had a problem. The WR has Waaaaaaay more power then any KLX even with a big bore, never had the clutch slip.

 

BUT the wr might have a clutch built to handle that power (as far as design). Can't really compare yamaha tech to kawi tech

 

just buy whatever is most expensive. just like race gas it'll make you faster.

vroom vroom

 

Rotella synthetic 5w40. Same as in my diesel truck. I am converting over to using this oil in everything. I used to be a mobile 1 synthetic guy but then it became hard to find.

 

Mobil 1 Super 4T 20-50w made for motorcycles

 

I use only motorcycle rated oil. Virtually no automobile oils have MA rating, but oddly enough the Rotella 5w40 has the JASO MA oil rating. That means it is compatible with the wet clutch integral gear box set up of a motorcycle.

I figure there are additives that are in there that are not permitted in car oils and there are additives in car oil that aren't in the Rotella diesel oil.

I don't use synthetic, although I have before. I just figure I've never seen a true oil failure in any engines in the 40 plus years I've been in motorcycles and the 22 years I was in and around a shop working full and part time, so I don't get too wound up about it. I did use Mobil 1 back in the 80s in my Gold Wing (pre-motorcycle synthetics) because it made the gear box and clutch work so much smoother in engaging gear and shifting.

I run around 5000 miles between changes because previous oil sample analysis when at the shop proved that the oil was far from out of spec at 2500-3000 miles and - again - never seen a true oil failure in a bike in regular street/off road use. The oil companies also support that interval or longer between changes. The oil we have is not the same as my grandfather's straight weight non-detergent oil of the 40s-60s nor is the engine metallurgy the same. Only failures I've seen were related to lack of oil, running out or, in the case of some Hondas, putting the filters in backward blocking the oil flow.

That is what I do and why.

 

Cool! I use Blackstone UOA to set OCI on my bikes & cars myself.

I'd be VERY interested to see a UOA report of conventional oil drained from a KLX250 after 5K miles. I haven't had my KLX long enough to push it that far. That should be vely intowesting. Care to share?