02 yz125 piston/top end

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4/30/2017 7:21 PM

Bought my friends 02 Yz125 that had like no compression for $450.cool Would you say this piston needs replacing? The rod bearing definitely is worn out. I have a Pro X top end kit coming on Tuesday just want some reassurement on this lol, thanks.Photo

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4/30/2017 7:37 PM

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4/30/2017 7:44 PM

The piston is toast, but I would be more concerned about what shape the cylinder is in and then what clearances do you have?

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4/30/2017 7:59 PM

xnationalwrench wrote:

The piston is toast, but I would be more concerned about what shape the cylinder is in and then what clearances do you have?

Ahhh that's what I wanted to hear. smile honestly the Cylinder doesn't seem like it's in bad condition. Compared to one that I have to send off to get replated and stuff. Not really any scratches or marks. Didn't check the clearances. I need to do that pinch

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4/30/2017 8:28 PM

xnationalwrench wrote:

The piston is toast, but I would be more concerned about what shape the cylinder is in and then what clearances do you have?

X2 on this.

Check the air boot to see if any sand got through the air filter. Looks like something got into the cylinder. If you find any sand or dirt in the air boot, rebuild the motor.

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/1/2017 4:26 AM

The piston ring looks like it is stuck in the piston ring land on the exhaust side. I would suggest that you try to find the cause.

Paw Paw

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5/1/2017 11:51 AM

xnationalwrench wrote:

The piston is toast, but I would be more concerned about what shape the cylinder is in and then what clearances do you have?

mattyhamz2 wrote:

X2 on this.

Check the air boot to see if any sand got through the air filter. Looks like something got into the cylinder. If you find any sand or dirt in the air boot, rebuild the motor.

Ima check the Cylinder and intake tonight. If I find no sand in the intake then what? Just slap the new top end in her and brap all weekend? laughing tongue obviously make sure the Cylinder is okay too. I'll post some pics of the Cylinder walls tonight

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5/1/2017 12:33 PM

Also the underside of the piston.
Also have the cylinder checked for out of round.
The bad scoring on the exhaust side of the piston sure looks like a "cold seize" where the engine was put under very heavy loads without the proper warming up of the engine.
The underside of the piston will give a good indication as to weather you have a leaking crank seal on the clutch side.

Paw Paw

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5/1/2017 1:00 PM

Paw Paw 271 wrote:

Also the underside of the piston.
Also have the cylinder checked for out of round.
The bad scoring on the exhaust side of the piston sure looks like a "cold seize" where the engine was put under very heavy loads without the proper warming up of the engine.
The underside of the piston will give a good indication as to weather you have a leaking crank seal on the clutch side.

Paw Paw

Will do and thank you. I'll post some more pics tonight when I get home.

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5/1/2017 2:15 PM

xnationalwrench wrote:

The piston is toast, but I would be more concerned about what shape the cylinder is in and then what clearances do you have?

mattyhamz2 wrote:

X2 on this.

Check the air boot to see if any sand got through the air filter. Looks like something got into the cylinder. If you find any sand or dirt in the air boot, rebuild the motor.

pmshortt2 wrote:

Ima check the Cylinder and intake tonight. If I find no sand in the intake then what? Just slap the new top end in her and brap all weekend? laughing tongue obviously make sure the Cylinder is okay too. I'll post some pics of the Cylinder walls tonight

Honestly, I'd just rebuild it anyways so you know you're starting off fresh with everything, but I don't know your budget. Post some pics of the bike though!

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/1/2017 6:55 PM

Paw Paw 271 wrote:

Also the underside of the piston.
Also have the cylinder checked for out of round.
The bad scoring on the exhaust side of the piston sure looks like a "cold seize" where the engine was put under very heavy loads without the proper warming up of the engine.
The underside of the piston will give a good indication as to weather you have a leaking crank seal on the clutch side.

Paw Paw

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5/1/2017 7:02 PM

That sure looks like a lot of dirt or sand in the intake.
I also see some serious markings above the exhaust port. It may be time for the cylinder to be reworked as well as the bottom end.

Paw Paw

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5/1/2017 7:03 PM

There's definitely some splatter of mud inside the intake boot. Not good. What does everyone think of the Cylinder? Honestly doesn't look too bad to me. ermm Photo

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5/1/2017 7:07 PM

Paw Paw 271 wrote:

That sure looks like a lot of dirt or sand in the intake.
I also see some serious markings above the exhaust port. It may be time for the cylinder to be reworked as well as the bottom end.

Paw Paw

Thank you for the insight, looks like I'll be hitting up millinium Technologies to get this Cylinder reworkedcool

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5/1/2017 8:07 PM

That's a lot of dirt!!!! I'd go through that entire motor for sure now. On the plus side, you'll have two fresh 125's!

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/2/2017 5:59 AM

mattyhamz2 wrote:

That's a lot of dirt!!!! I'd go through that entire motor for sure now. On the plus side, you'll have two fresh 125's!

Yeah forreal lol. I suppose it's time to invest in a Tusk case splitter. It's intimidating but honestly I think it'll be like anything else. When I got my 97 I had no idea how to maintain and install and remove all the parts....now it's all easy to me. So hopefully after doing this a time or two it'll become "easy." Wish me luck smile

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5/2/2017 6:18 AM

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5/2/2017 8:12 AM

pmshortt2 wrote: Photo

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looks like an 01, not an 02. Good thing is you have two bikes that share a lot of parts!

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/2/2017 10:50 AM

I need to look up the VIN. Ima be pissed if it's an 01 because I just got my pistion kit for an 02....

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5/2/2017 12:38 PM

pmshortt2 wrote:

I need to look up the VIN. Ima be pissed if it's an 01 because I just got my pistion kit for an 02....

96-01 has the same style plastic. 2002 was the year they changed to the plastic that stuck around until 2014.

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/2/2017 12:39 PM

Photo

here is a picture of the 2002
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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/2/2017 1:03 PM

mattyhamz2 wrote: Photo

here is a picture of the 2002

Yeah I'm seeing that now as 01 had the white airbox. I'm pretty pissed off right now tbh. After telling my friends "it's an 01 right" he replied "no it's an 02." "Oh okay" ordered all parts for an 02 and now look at my dumbass. Another weekend no riding laughing angry pinch

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5/2/2017 1:31 PM

mattyhamz2 wrote: Photo

here is a picture of the 2002

pmshortt2 wrote:

Yeah I'm seeing that now as 01 had the white airbox. I'm pretty pissed off right now tbh. After telling my friends "it's an 01 right" he replied "no it's an 02." "Oh okay" ordered all parts for an 02 and now look at my dumbass. Another weekend no riding laughing angry pinch

Ah man! That's a bummer! At least you have two very similar bikes

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

5/2/2017 2:25 PM

mattyhamz2 wrote: Photo

here is a picture of the 2002

pmshortt2 wrote:

Yeah I'm seeing that now as 01 had the white airbox. I'm pretty pissed off right now tbh. After telling my friends "it's an 01 right" he replied "no it's an 02." "Oh okay" ordered all parts for an 02 and now look at my dumbass. Another weekend no riding laughing angry pinch

mattyhamz2 wrote:

Ah man! That's a bummer! At least you have two very similar bikes

Yeah at least there's a positive out of this grin

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