duck
Life time member
Number of posts : 4445
Any oil that gets changed regularly. K bike engines are "bulletproof" and short of running them dry will not fail from anything caused by what oil you use.
I've been using synthetic oil in many K bikes for years and years. No issues. I usually run Mobil 1 15-50 or Shell Rotella T6 5-40.
Tires are much more important than oil.
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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT