Is mixing 20w50 and 10w40 half and half ok in Yz125

Sm450R
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Modesto, CA, USA

Need to get oil change done before trip, problem is I’m not sure if I can mix 20w50 and 10w40…want to make sure won’t make transmission get to hot etc…Thanks!

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Gator 4
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12/28/2024 9:45pm

Shouldn't cause any problems.  I always run exactly what the manual calls for.

Sm450R
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12/28/2024 9:52pm
Gator 4 wrote:

Shouldn't cause any problems.  I always run exactly what the manual calls for.

Well thanks for the answer, trip just got canceled cause my crank seal is BLOWN…missing 250ml of oil, was just done 5 hours ago.

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MxAddic
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12/29/2024 5:58am
Gator 4 wrote:

Shouldn't cause any problems.  I always run exactly what the manual calls for.

Sm450R wrote:

Well thanks for the answer, trip just got canceled cause my crank seal is BLOWN…missing 250ml of oil, was just done 5 hours ago.

Check your bearings Bro.

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Sm450R
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12/30/2024 2:03pm
Gator 4 wrote:

Shouldn't cause any problems.  I always run exactly what the manual calls for.

Sm450R wrote:

Well thanks for the answer, trip just got canceled cause my crank seal is BLOWN…missing 250ml of oil, was just done 5 hours ago.

MxAddic wrote:

Check your bearings Bro.

Bearings are fine

The Shop

MxAddic
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12/30/2024 2:12pm
Sm450R wrote:

Bearings are fine

They why did your seal blow?

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Sm450R
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12/30/2024 2:17pm
Sm450R wrote:

Bearings are fine

MxAddic wrote:

They why did your seal blow?

Well I bought the bike a month ago and when I torn it down the seal was all dried up, it’s super weird

MxAddic
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12/30/2024 2:20pm
Sm450R wrote:

Well I bought the bike a month ago and when I torn it down the seal was all dried up, it’s super weird

Yeah, it happens.

GL! 

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soggy
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12/30/2024 5:36pm

 If a new crank seal blew in 5 hours it was either damaged on install or your crank hearings are shot. 

Gator 4
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12/30/2024 6:47pm

FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal would be leaking the fuel/oil that you mix with your gasoline.

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Sm450R
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12/30/2024 6:52pm
soggy wrote:

 If a new crank seal blew in 5 hours it was either damaged on install or your crank hearings are shot. 

😂 I only did a top end…haven’t touched the bottom end…

Sm450R
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12/30/2024 6:53pm Edited Date/Time 12/30/2024 6:54pm
Gator 4 wrote:
FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal...

FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal would be leaking the fuel/oil that you mix with your gasoline.

No I’ve owned a few, 2 85’s and this is my first 125. Don’t understand what your saying here… blown crank seal was making it suck in transmission oil.

Sm450R
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Modesto, CA, USA
12/31/2024 1:33pm
Gator 4 wrote:

Shouldn't cause any problems.  I always run exactly what the manual calls for.

Sm450R wrote:

Well thanks for the answer, trip just got canceled cause my crank seal is BLOWN…missing 250ml of oil, was just done 5 hours ago.

MxAddic wrote:

Check your bearings Bro.

Welp, checked the flywheel side bearing and it has a small amount of play so I’m just gonna replace both

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MxAddic
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12/31/2024 1:36pm Edited Date/Time 12/31/2024 1:38pm
Sm450R wrote:

Well thanks for the answer, trip just got canceled cause my crank seal is BLOWN…missing 250ml of oil, was just done 5 hours ago.

MxAddic wrote:

Check your bearings Bro.

Sm450R wrote:

Welp, checked the flywheel side bearing and it has a small amount of play so I’m just gonna replace both

Yes, you are unlikely to run into a situation where you would only replace one.

It's going to run like new now.

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captmoto
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1/4/2025 3:01pm Edited Date/Time 1/4/2025 3:02pm
Gator 4 wrote:
FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal...

FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal would be leaking the fuel/oil that you mix with your gasoline.

Not true. I had a CR250 that ran lean in left turns then would load up when I pulled into the pits. When the clutch side seal is bad it sucks air or gear oil.

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1
1/7/2025 6:17pm
Gator 4 wrote:
FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal...

FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal would be leaking the fuel/oil that you mix with your gasoline.

The few times I’ve had RH crank seals let go on a two stroke they always suck trans oil, never once had fuel contaminate my transmission oil. 

1
Gator 4
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1/7/2025 9:13pm
Gator 4 wrote:
FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal...

FYI - if you are new to 2 strokes, the oil you put in the transmission is separate from the crank seal leaking.  The crank seal would be leaking the fuel/oil that you mix with your gasoline.

Rickyisms wrote:
The few times I’ve had RH crank seals let go on a two stroke they always suck trans oil, never once had fuel contaminate my transmission...

The few times I’ve had RH crank seals let go on a two stroke they always suck trans oil, never once had fuel contaminate my transmission oil. 

I am so used the flywheel side leaking, I forgot about the tranny side...  lol.  Thx.

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