how often should i change trans oil?

Eric_Bakker
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Eric_Bakker
i am new to riding and have a 01 yz125 2t
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kb228
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kb228 6/9/2019 5:35pm
6/9/2019 5:35pm
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PTECH
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PTECH 6/9/2019 5:47pm
6/9/2019 5:47pm
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life. Is it because of the clutch? Still I would think it doesn't see the kind of heat in the cylinder head of a 4 stroke?

My riding buddy changes the oil in his cr125 about every 30 hours (I know because I let him store his bike at my house) and with the hills we do he's beating the clutch to death a lot. I always give him shit about it but he just shrugs and says piss on it, lets ride! I change mine every 12-15 hours.
kb228
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kb228 6/10/2019 3:53am
6/10/2019 3:53am
PTECH wrote:
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life...
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life. Is it because of the clutch? Still I would think it doesn't see the kind of heat in the cylinder head of a 4 stroke?

My riding buddy changes the oil in his cr125 about every 30 hours (I know because I let him store his bike at my house) and with the hills we do he's beating the clutch to death a lot. I always give him shit about it but he just shrugs and says piss on it, lets ride! I change mine every 12-15 hours.
With clutch debris and other crap in there, its peace of mind. Engine rebuilds are expensive and even more so if it blows up. Oil is cheap insurance imo

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PTECH
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PTECH 6/10/2019 7:59pm
6/10/2019 7:59pm
PTECH wrote:
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life...
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life. Is it because of the clutch? Still I would think it doesn't see the kind of heat in the cylinder head of a 4 stroke?

My riding buddy changes the oil in his cr125 about every 30 hours (I know because I let him store his bike at my house) and with the hills we do he's beating the clutch to death a lot. I always give him shit about it but he just shrugs and says piss on it, lets ride! I change mine every 12-15 hours.
kb228 wrote:
With clutch debris and other crap in there, its peace of mind. Engine rebuilds are expensive and even more so if it blows up. Oil is...
With clutch debris and other crap in there, its peace of mind. Engine rebuilds are expensive and even more so if it blows up. Oil is cheap insurance imo
Other crap? What other crap? We’re taking about transmission oil in a 2 stroke here... not engine oil so changing it will have no effect on how frequently you have to rebuild your engine.
Turbojez
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Turbojez 6/11/2019 3:07am
6/11/2019 3:07am
PTECH wrote:
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life...
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life. Is it because of the clutch? Still I would think it doesn't see the kind of heat in the cylinder head of a 4 stroke?

My riding buddy changes the oil in his cr125 about every 30 hours (I know because I let him store his bike at my house) and with the hills we do he's beating the clutch to death a lot. I always give him shit about it but he just shrugs and says piss on it, lets ride! I change mine every 12-15 hours.
kb228 wrote:
With clutch debris and other crap in there, its peace of mind. Engine rebuilds are expensive and even more so if it blows up. Oil is...
With clutch debris and other crap in there, its peace of mind. Engine rebuilds are expensive and even more so if it blows up. Oil is cheap insurance imo
PTECH wrote:
Other crap? What other crap? We’re taking about transmission oil in a 2 stroke here... not engine oil so changing it will have no effect on...
Other crap? What other crap? We’re taking about transmission oil in a 2 stroke here... not engine oil so changing it will have no effect on how frequently you have to rebuild your engine.
Plenty of metal to metal contact in the gearbox (small particles of metal/shavings in worst case), also clutch plates wear out. All that debris pollutes the oil and then goes in between the clutch parts and gear teeth every single time it passes through. Given enough time and debris in the oil, it will eventually start wearing the transmission and clutch at an increased rate.

Cheaper and easier to replace the oil more often, then to split the cases to get to failed bearings/replace gears.
Like KB228 said, it's mainly for insurance/a peace of mind, as you would have to run the oil through the lab every couple of hours to know, when it starts losing it's properties.
Alec138
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Alec138 6/12/2019 8:46am
6/12/2019 8:46am
Every 5-10hrs. Used to change it based off rides on old bikes but now that i have something nice, i change it even if it needs it or not. $20 is nothing for good oil.
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zippytech
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zippytech 6/13/2019 6:22am
6/13/2019 6:22am
my cr 250 has well over 1000 + hours on the trans. I change it every 5 gallon of gas. I also have had the same clutches in the bike for the last 500+ hours.. Changing the trans oil cuts down on wear to the shafts the gears spin on and such. A quart of Honda trans oil is less than 10 bucks.
jamiehughes
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jamiehughes 6/13/2019 12:25pm
6/13/2019 12:25pm
PTECH wrote:
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life...
I've always wondered whats the logic for changing two stroke transmission oil so frequently? I would think otherwise transmission oil would have a relatively easy life. Is it because of the clutch? Still I would think it doesn't see the kind of heat in the cylinder head of a 4 stroke?

My riding buddy changes the oil in his cr125 about every 30 hours (I know because I let him store his bike at my house) and with the hills we do he's beating the clutch to death a lot. I always give him shit about it but he just shrugs and says piss on it, lets ride! I change mine every 12-15 hours.
look up something called "gear shear"..that is why it's still super important to change trans oil regularly.. the constant "shear" pressure on the oil as it is squished thru the gears over time breaks the viscosity of the oil down..

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