927 VS K2 what’s better for a 125?

97Yz
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12/28/2024
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Modesto, CA, USA
Edited Date/Time 6/29/2025 7:26pm

I’m tired of listening to people tell me to run 927 or k2, so before I chose which I’m gonna run I wanna hear other people’s opinions on what oil will be best in a yz125 that gets a mix of moto and woods. When I run woods and moto I do ride the bike pretty hard in the high to mid rpm majority of the time. Also I would like to run top ends for 80-100 hours…

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6/29/2025 7:29pm Edited Date/Time 6/29/2025 7:33pm

Ratio and jetting is 10x more important than the oil. Even low end oils are still decent these days. 927 will smell better but good luck cleaning the powervalves, especially with a top end interval of 80-100 hours. 

Top amateur kid on a supermini, I’d give the nod to 927. But I bet the kawi kids are still on k2 these days, as the oil wouldn’t be the reason for a failure 

2
Alex814
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USA
6/29/2025 8:42pm

80-100 hours on a 125 top end doesn't sound like a good idea...

Motul 800 in mine at 32:1. Came from using 927 and it wasn't as messy as some claim, but I'm going to stick with Motul. 

2
97Yz
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Modesto, CA, USA
6/29/2025 8:51pm
Alex814 wrote:
80-100 hours on a 125 top end doesn't sound like a good idea...Motul 800 in mine at 32:1. Came from using 927 and it wasn't as...

80-100 hours on a 125 top end doesn't sound like a good idea...

Motul 800 in mine at 32:1. Came from using 927 and it wasn't as messy as some claim, but I'm going to stick with Motul. 

I’ve done it many times with forged pistons. Never had a failure.

1
97Yz
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Modesto, CA, USA
6/29/2025 10:35pm
Ratio and jetting is 10x more important than the oil. Even low end oils are still decent these days. 927 will smell better but good luck...

Ratio and jetting is 10x more important than the oil. Even low end oils are still decent these days. 927 will smell better but good luck cleaning the powervalves, especially with a top end interval of 80-100 hours. 

Top amateur kid on a supermini, I’d give the nod to 927. But I bet the kawi kids are still on k2 these days, as the oil wouldn’t be the reason for a failure 

I do rings every 40 hours so that would allow me to clean up power valves

1

The Shop

6/30/2025 8:56am

What is the difference in 927 & k2 ?  The price is crazy high.  I run Klotz techno plate I think it’s called , it smells great.  My plating has the piston tolerance Very tight.  I was thinking 20 hrs on piston & re ring at 10 hrs.  If the weather would cooperate I can ride .  Depending on how it pulls I might increase the hrs by 5. 

97Yz
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32
Joined
12/28/2024
Location
Modesto, CA, USA
6/30/2025 9:35am
What is the difference in 927 & k2 ?  The price is crazy high.  I run Klotz techno plate I think it’s called , it smells...

What is the difference in 927 & k2 ?  The price is crazy high.  I run Klotz techno plate I think it’s called , it smells great.  My plating has the piston tolerance Very tight.  I was thinking 20 hrs on piston & re ring at 10 hrs.  If the weather would cooperate I can ride .  Depending on how it pulls I might increase the hrs by 5. 

20 hours??? That’s crazy low hour for a forged piston.

1
JMX247
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10/26/2014
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Santa Clarita, CA, USA
Fantasy
6/30/2025 4:14pm
97Yz wrote:

20 hours??? That’s crazy low hour for a forged piston.

That depends on hard you beat on the bike, I change 125 pistons every 10-12 hours but its different for everyone. Also to answer the other question we use K2 and have had good luck with it so far, Powervalves look clean every time the cylinder comes apart. 

de883zx
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164
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12/26/2013
Location
Howell, MI, USA
6/30/2025 5:48pm

Bought a 24 kx250 and was wondering if someone makes a  air box plug that goes in the side panel so when I power wash I don’t get water in the air box. Sick of taping up the opening all the time and cleaning off the tape residue. Make sense? Filter doesn’t get dirty enough sometimes to remove and twin air box cover the whole thing remove side panel etc. or any other ideas I’m open to. 

1
Falcon
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11/16/2011
Location
Menifee, CA, USA
7/2/2025 11:16am

K2. It's a synthetic and burns far cleaner. 927 smells awesome, but for a post-'70s 2-stroke with power valves, you'll do better with the synthetic oils, long-term. 

1

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