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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Kchop on September 20, 2025, 02:57:56 PM

Title: Oil for K75s
Post by: Kchop on September 20, 2025, 02:57:56 PM

Hey Group, (1993 k 75s)

Thought it would be easy to look up...

I know it's been asked somewhere here, but what oil are you guys using for your K bikes?

Full synthetic
Semi synthetic
Dyno
20w50??
Thanks

Title: Re: Oil for K75s
Post by: Woytas on September 21, 2025, 11:33:49 AM

VALVOLINE VR1 RACING 20W-50

Title: Re: Oil for K75s
Post by: Kchop on September 22, 2025, 12:44:44 PM

Changing the gear oil for the first time on my own. Checking to see if my assumption is correct.

Bottle of gear oil is 1L= 1000ml, k75s wants .85L...take out 150ml and I should be good yes?

trying to fashion a dipstick based on previous posts here...

Title: Re: Oil for K75s
Post by: Laitch on September 23, 2025, 12:13:55 AM

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(https://motobrick.com/gallery/4/1601-230925000557.png)(https://motobrick.com/gallery/4/1601-230925000516.png)

Title: Re: Oil for K75s
Post by: Kchop on September 25, 2025, 08:21:03 AM

hey, according to my manual it says to run bike before changing the gear oil. Anyone have an experience with this? Is it just for easier flow?

thanks

93 k75S

Title: Re: Oil for K75s
Post by: Laitch on September 25, 2025, 08:51:13 AM

Quote from: Kchop on September 25, 2025, 08:21:03 AM

hey, according to my manual it says to run bike before changing the gear oil.

Take it for a ride before changing oil in the transmission, rear drive, engine and fork tubes. Coolant can be changed cold. Verify the fill plug can removed first, remove it, then remove the drain plug.
If the manual can't be believed, it's dead weight. Recycle it or shred it for your gerbil's bedding.

Title: Re: Oil for K75s
Post by: Kchop on September 25, 2025, 10:03:33 AM

 :laughing1: ok, that got me laughing out loud....kudos

Title: Re: Oil for K75s
Post by: Kaos on September 27, 2025, 01:53:09 AM

Quote from: Kchop on September 22, 2025, 12:44:44 PM

Bottle of gear oil is 1L= 1000ml, k75s wants .85L...take out 150ml and I should be good yes?

"Laughs in metric"

Title: Re: Oil for K75s
Post by: frankenduck on September 27, 2025, 08:03:08 PM

I run a 50/50 mix of Mobil 1 15-50 and Mobil 1 10-40 High Mileage. The high mileage oil has additives to rejuvenate rubber and my hopeful theory is that it will keep the rear main seal, clutch O-ring and water pump seal from going bad.

Title: Re: Oil for K75s
Post by: TriSpark on October 03, 2025, 02:22:28 PM

When I first joined up, the recommendation was Mobil 1 15w/50 synthetic and I've being using that with no problem since then. When I had my K100 in London in 1990 that got Castrol GTX 20w/50 at each oil change and was happy with it.