2020 yz250f cam chain problems

moto551
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moto551
Edited Date/Time 11/6/2021 8:42pm
What's causing the cam chain breaks on the 2020 yz250f?
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redduk
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redduk 7/21/2021 3:45pm
7/21/2021 3:45pm
News to me, we're is this info coming from.
moto551
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moto551 7/21/2021 4:16pm
7/21/2021 4:16pm
Past posts and my sons bike at 30hrs.
walent215
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walent215 7/21/2021 4:48pm
7/21/2021 4:48pm
Broke cam chain @ 30 hours
Hmmm
Pics of shrapnel?
Billet526
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Billet526 7/21/2021 7:33pm
7/21/2021 7:33pm

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Rider 5280
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Rider 5280 7/21/2021 9:47pm
7/21/2021 9:47pm Edited Date/Time 7/21/2021 10:05pm
So sorry to hear that.

Does the automatic cam-chain tensioner still seem to be working?
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moto551
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moto551 7/22/2021 6:22am
7/22/2021 6:22am
Cam chain tensioner seems to be okay. I believe the chain is breaking on its on. Always check your filter strainer by the shifter for plastic debree. The chain will start eating you guides.
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walent215
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walent215 7/22/2021 7:09am
7/22/2021 7:09am
Billet526 wrote:
[img]https://p.vitalmx.com/photos/forums/2021/07/21/502545/s1200_IMG_1696.jpg[/img]

did this take out your valve train with it?
moto551
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moto551 8/11/2021 2:50pm
8/11/2021 2:50pm
Billet526 wrote:
[img]https://p.vitalmx.com/photos/forums/2021/07/21/502545/s1200_IMG_1696.jpg[/img]

walent215 wrote:
did this take out your valve train with it?
My broken cam chain resulted into bent exhaust valves. Replacing all valves and sending head to TZR for further inspection.
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hubbardmx50
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hubbardmx50 8/11/2021 9:17pm
8/11/2021 9:17pm
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he said his oil filter had some black shavings on it last time he changed it. I told him to take a photo next time he changes it. Im thinking maybe clutch shavings?
moto551
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moto551 8/12/2021 10:40am
8/12/2021 10:40am
hubbardmx50 wrote:
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he...
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he said his oil filter had some black shavings on it last time he changed it. I told him to take a photo next time he changes it. Im thinking maybe clutch shavings?
Have him look at the strainer that's located by his shifter. If any plastic found that would indicate chain guide wear. Cam chain starts to break apart and eat the guides.
GetItOnLikeTron 8/25/2021 5:38pm
8/25/2021 5:38pm
Yamahas have weak cam chains. The chains stretch from over rev. The chain can only stretch so far before it snap. It is extremely important to change timing chains every top end.
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Skerby
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Skerby 8/25/2021 7:09pm
8/25/2021 7:09pm
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
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moto551
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moto551 8/25/2021 7:14pm
8/25/2021 7:14pm
Skerby wrote:
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
I heard the same today. Updated cam chain, tensioner, and cams.
Rider 5280
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Rider 5280 8/25/2021 8:11pm
8/25/2021 8:11pm
Hmmm ... backward compatible to older models (2014-?) do you think?
Rider 5280
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Rider 5280 8/25/2021 9:39pm
8/25/2021 9:39pm Edited Date/Time 8/26/2021 7:43am
Skerby wrote:
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016).

I researched this via Rocky Mountain ATV's OEM parts finder just now and found the following.

From what I can see, the Manufacturer's part numbers (Yamaha's) are the same for all cam chains 2016-2022 (it's P/N 94591-77114-00), BUT ... the Rocky Mountain part numbers for all of these years are NOT the same ... AND you'll notice a double dash in the part number for the the 21-22 chain. I chalk this up to "employee data entry error." So I defaulted to the Rocky Mountain part numbers > which is how I group them with my crayon skillz below. Viewed this way, this confirms the cam chains DID change in 2021 as people have stated.

When I did the same thing for the cam chain tensioners, the results were straightforward - unique part numbers were evident/no conflicting info. Again, I used my crayon skillz below to indicate the differences below.

Finally, FWIW, I also noticed that the improved parts on the 21-22 YZ250F are also less expensive than the earlier models.

So, I ordered 2 of the 21-22 cam chains and 1 cam chain tensioner to see if they are different than my 2016 equivalent parts that I have on hand. If they are, and they look compatible/interchangeable, I'll run the newer versions in hopes of lower probability of failure.

1
1
Rider 5280
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Rider 5280 8/25/2021 9:48pm
8/25/2021 9:48pm
Skerby wrote:
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
Rider 5280 wrote:
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016). I researched this via Rocky Mountain...
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016).

I researched this via Rocky Mountain ATV's OEM parts finder just now and found the following.

From what I can see, the Manufacturer's part numbers (Yamaha's) are the same for all cam chains 2016-2022 (it's P/N 94591-77114-00), BUT ... the Rocky Mountain part numbers for all of these years are NOT the same ... AND you'll notice a double dash in the part number for the the 21-22 chain. I chalk this up to "employee data entry error." So I defaulted to the Rocky Mountain part numbers > which is how I group them with my crayon skillz below. Viewed this way, this confirms the cam chains DID change in 2021 as people have stated.

When I did the same thing for the cam chain tensioners, the results were straightforward - unique part numbers were evident/no conflicting info. Again, I used my crayon skillz below to indicate the differences below.

Finally, FWIW, I also noticed that the improved parts on the 21-22 YZ250F are also less expensive than the earlier models.

So, I ordered 2 of the 21-22 cam chains and 1 cam chain tensioner to see if they are different than my 2016 equivalent parts that I have on hand. If they are, and they look compatible/interchangeable, I'll run the newer versions in hopes of lower probability of failure.


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Skerby
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Skerby 8/26/2021 7:46am
8/26/2021 7:46am
I can attest to the transmission changes. Riding my 21 back to back with a 20, the 20 shift muchs smoother and easier. 21 is more notchy, but probably has better engagement.

Not a detractor at all on the 21, just something I notice going back and forth, bothbikes had low hours.
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moto551
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moto551 9/5/2021 7:50pm
9/5/2021 7:50pm
Update,
Had to replace exhaust valves due them being bent. TZR cut seats and assembled. I got lucky that I only replaced valves,cam chain, tensioner, flywheel rotor, and piston kit.
About $800.
hubbardmx50
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hubbardmx50 9/8/2021 12:02pm
9/8/2021 12:02pm
hubbardmx50 wrote:
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he...
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he said his oil filter had some black shavings on it last time he changed it. I told him to take a photo next time he changes it. Im thinking maybe clutch shavings?
moto551 wrote:
Have him look at the strainer that's located by his shifter. If any plastic found that would indicate chain guide wear. Cam chain starts to break...
Have him look at the strainer that's located by his shifter. If any plastic found that would indicate chain guide wear. Cam chain starts to break apart and eat the guides.
Cool yeah I will let him know. So, were the cam chain guides updated for 21 along with all of those other parts?
moto551
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moto551 9/8/2021 2:42pm
9/8/2021 2:42pm
hubbardmx50 wrote:
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he...
Wow, that sucks. I wonder if the 22 cam chain will be different. My buddy has a 20, no issues with cam chain yet but he said his oil filter had some black shavings on it last time he changed it. I told him to take a photo next time he changes it. Im thinking maybe clutch shavings?
moto551 wrote:
Have him look at the strainer that's located by his shifter. If any plastic found that would indicate chain guide wear. Cam chain starts to break...
Have him look at the strainer that's located by his shifter. If any plastic found that would indicate chain guide wear. Cam chain starts to break apart and eat the guides.
hubbardmx50 wrote:
Cool yeah I will let him know. So, were the cam chain guides updated for 21 along with all of those other parts?
I don't know.
hubbardmx50
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hubbardmx50 11/1/2021 11:04am
11/1/2021 11:04am
Oil filter and strainer on my buddy’s 2020. Anybody else’s filter come out this dark? He’s a 50 yearold vet rider using maxima ester formula oil.

Rider 5280
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Rider 5280 11/1/2021 11:58am
11/1/2021 11:58am
Mine does. Both on 2016 YZ250F and 2020 YZ450F. 3-5 hours and it looks like that. Miniscule oil volume ... not crazy about that.
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hubbardmx50
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hubbardmx50 11/1/2021 12:48pm
11/1/2021 12:48pm
Rider 5280 wrote:
Mine does. Both on 2016 YZ250F and 2020 YZ450F. 3-5 hours and it looks like that. Miniscule oil volume ... not crazy about that.
Okay. I’m on Honda’s (obviously you know this from my other thread) but mine come out pretty dark too. I think as long as that strainer is clear he is fine.
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Johnnydirt
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Johnnydirt 11/5/2021 4:18am
11/5/2021 4:18am
Skerby wrote:
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
Rider 5280 wrote:
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016). I researched this via Rocky Mountain...
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016).

I researched this via Rocky Mountain ATV's OEM parts finder just now and found the following.

From what I can see, the Manufacturer's part numbers (Yamaha's) are the same for all cam chains 2016-2022 (it's P/N 94591-77114-00), BUT ... the Rocky Mountain part numbers for all of these years are NOT the same ... AND you'll notice a double dash in the part number for the the 21-22 chain. I chalk this up to "employee data entry error." So I defaulted to the Rocky Mountain part numbers > which is how I group them with my crayon skillz below. Viewed this way, this confirms the cam chains DID change in 2021 as people have stated.

When I did the same thing for the cam chain tensioners, the results were straightforward - unique part numbers were evident/no conflicting info. Again, I used my crayon skillz below to indicate the differences below.

Finally, FWIW, I also noticed that the improved parts on the 21-22 YZ250F are also less expensive than the earlier models.

So, I ordered 2 of the 21-22 cam chains and 1 cam chain tensioner to see if they are different than my 2016 equivalent parts that I have on hand. If they are, and they look compatible/interchangeable, I'll run the newer versions in hopes of lower probability of failure.

How’d you make out with the cam chain tensioner? I ordered a new chain for my 17 and your correct they seem to all have the P/N for the updated one.
Rider 5280
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Rider 5280 11/5/2021 11:19am
11/5/2021 11:19am
Skerby wrote:
They claimed to have 'updated' cam chain for 2021. It was a bullet point.
Rider 5280 wrote:
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016). I researched this via Rocky Mountain...
I am personally interested in knowing about the 2016-2022 YZ250F cam chains & cam chain tensioners (I have a 2016).

I researched this via Rocky Mountain ATV's OEM parts finder just now and found the following.

From what I can see, the Manufacturer's part numbers (Yamaha's) are the same for all cam chains 2016-2022 (it's P/N 94591-77114-00), BUT ... the Rocky Mountain part numbers for all of these years are NOT the same ... AND you'll notice a double dash in the part number for the the 21-22 chain. I chalk this up to "employee data entry error." So I defaulted to the Rocky Mountain part numbers > which is how I group them with my crayon skillz below. Viewed this way, this confirms the cam chains DID change in 2021 as people have stated.

When I did the same thing for the cam chain tensioners, the results were straightforward - unique part numbers were evident/no conflicting info. Again, I used my crayon skillz below to indicate the differences below.

Finally, FWIW, I also noticed that the improved parts on the 21-22 YZ250F are also less expensive than the earlier models.

So, I ordered 2 of the 21-22 cam chains and 1 cam chain tensioner to see if they are different than my 2016 equivalent parts that I have on hand. If they are, and they look compatible/interchangeable, I'll run the newer versions in hopes of lower probability of failure.

Johnnydirt wrote:
How’d you make out with the cam chain tensioner? I ordered a new chain for my 17 and your correct they seem to all have the...
How’d you make out with the cam chain tensioner? I ordered a new chain for my 17 and your correct they seem to all have the P/N for the updated one.
I still haven't rebuilt my bike, so no data yet.
adam8781
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adam8781 11/6/2021 8:42pm
11/6/2021 8:42pm
yz250f uses a dainty cam chain, this has been an issue with fast guys since 2014, 15-20 hours is what pros were swapping them out at, if ridden like regular guy 40-50 hours is about all id trust them for.

even on the 2020, id not go over 40 hours tops
romain524
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romain524 11/6/2021 11:42pm
11/6/2021 11:42pm
adam8781 wrote:
yz250f uses a dainty cam chain, this has been an issue with fast guys since 2014, 15-20 hours is what pros were swapping them out at...
yz250f uses a dainty cam chain, this has been an issue with fast guys since 2014, 15-20 hours is what pros were swapping them out at, if ridden like regular guy 40-50 hours is about all id trust them for.

even on the 2020, id not go over 40 hours tops
I know some fast amateur kids their mechanics change the timing chain every 5h to make sure it doesn’t break.

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