1980/81 Yamaha YZ 465 expert's?

GIwasB4
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GIwasB4
Edited Date/Time 3/2/2019 9:48am
Can you confirm if the 1981 YZ250 frame is the same as the 1981 YZ465?
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barnett468
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barnett468 2/28/2019 5:26pm
2/28/2019 5:26pm Edited Date/Time 2/28/2019 8:44pm
absolutely not the same frame, also, the steering head angle is much steeper on the 81 465 than on the 80 465. if you want to do 100 + mph in the desert, get a 1980 465 frame. if you want to do mx or tight trails and ever want to be able to turn easily, get an 81 465 frame. the 1981465 frame also has a steeper steering angle than a 1980 yz250.



lots of other parts are different as well.
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GIwasB4
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GIwasB4 2/28/2019 7:25pm
2/28/2019 7:25pm
So a 1981 YZ250 and 1981 YZ465 share the same frame?
newmann
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newmann 2/28/2019 7:34pm
2/28/2019 7:34pm
GIwasB4 wrote:
So a 1981 YZ250 and 1981 YZ465 share the same frame?
I did buy a 81 YZ250 engine from Steve Sage in Co. that he had taken out and replaced with a 465 engine. Just used the 465 mounts/ head stay.
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barnett468
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barnett468 2/28/2019 8:40pm
2/28/2019 8:40pm
GIwasB4 wrote:
So a 1981 YZ250 and 1981 YZ465 share the same frame?
no, and they are different part numbers and a 1980 and 1981 yz250 frame are different part numbers also, but from what newman says, the engines are interchangeable.
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GIwasB4
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GIwasB4 3/1/2019 5:58am
3/1/2019 5:58am
Thanks for the replies
barnett468
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barnett468 3/1/2019 7:21am
3/1/2019 7:21am
The critical things like all the suspension mounting points are the same. The 80 465 swing arm is 1 inch longer than the 80 250 swingarm and overall, the 465 arm is a good upgrade to the 80 260. The 81 465 uses a larger rear axle so the rear hub and swing arm and swing arm spacers are different than the 80 465 and 80 250. The 81 465 rear shock has better valving than the 80 465.
Russ14
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Russ14 3/1/2019 2:45pm
3/1/2019 2:45pm
The frames on the 81 models are the same the 250 part # is 4v4-21110-00-00, which 4v4 is the prefix for the 465.
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barnett468
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barnett468 3/1/2019 6:15pm
3/1/2019 6:15pm
Russ14 wrote:
The frames on the 81 models are the same the 250 part # is 4v4-21110-00-00, which 4v4 is the prefix for the 465.
Wrong, the 1981 465 frame is p/n 4V4-21425-00-00 which is a different number than the 1981 250 frame.

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GIwasB4
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GIwasB4 3/1/2019 6:57pm
3/1/2019 6:57pm
My title to the 1981 YZ465 frame

GIwasB4
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GIwasB4 3/1/2019 6:59pm
3/1/2019 6:59pm
So here's in a nutshell: I can buy a 1981 YZ250 frame and transfer all components from my broken 1981 YZ465 frame to it?
barnett468
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barnett468 3/1/2019 7:11pm
3/1/2019 7:11pm
GIwasB4 wrote:
My title to the 1981 YZ465 frame [img]https://p.vitalmx.com/photos/forums/2019/03/01/328941/s1200_4v4.jpg[/img]
My title to the 1981 YZ465 frame

ummm...what's the point?

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barnett468
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barnett468 3/1/2019 7:16pm
3/1/2019 7:16pm Edited Date/Time 3/1/2019 7:16pm
GIwasB4 wrote:
So here's in a nutshell: I can buy a 1981 YZ250 frame and transfer all components from my broken 1981 YZ465 frame to it?
I wouldn't guarantee that since the frames are in fact different.

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newmann
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newmann 3/1/2019 7:55pm
3/1/2019 7:55pm
GIwasB4 wrote:
So here's in a nutshell: I can buy a 1981 YZ250 frame and transfer all components from my broken 1981 YZ465 frame to it?
barnett468 wrote:
I wouldn't guarantee that since the frames are in fact different.

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What is different from a 81 250 and 465 frame? All of your comparisons above were from 80 a 81 unless I misread something. Of course alcohol may be involved...I will read it again in the morning.Laughing
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GIwasB4
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GIwasB4 3/1/2019 8:06pm
3/1/2019 8:06pm
newmann wrote:
What is different from a 81 250 and 465 frame? All of your comparisons above were from 80 a 81 unless I misread something. Of course...
What is different from a 81 250 and 465 frame? All of your comparisons above were from 80 a 81 unless I misread something. Of course alcohol may be involved...I will read it again in the morning.Laughing
1981 YZ465 broken frame-transfer all components of 1981 YZ465 to 1981 YZ250 frame?
GIwasB4
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GIwasB4 3/1/2019 8:09pm
3/1/2019 8:09pm
GIwasB4 wrote:
1981 YZ465 broken frame-transfer all components of 1981 YZ465 to 1981 YZ250 frame?
after this: tomorrow

barnett468
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barnett468 3/1/2019 9:26pm
3/1/2019 9:26pm Edited Date/Time 3/1/2019 9:50pm
GIwasB4 wrote:
So here's in a nutshell: I can buy a 1981 YZ250 frame and transfer all components from my broken 1981 YZ465 frame to it?
barnett468 wrote:
I wouldn't guarantee that since the frames are in fact different.

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newmann wrote:
What is different from a 81 250 and 465 frame? All of your comparisons above were from 80 a 81 unless I misread something. Of course...
What is different from a 81 250 and 465 frame? All of your comparisons above were from 80 a 81 unless I misread something. Of course alcohol may be involved...I will read it again in the morning.Laughing
I do not know exactly, but since they have different part numbers, something is definitely different. It may be something as small as a bracket, but unless anyone has tried this swap, no one knows for sure, which is why I wouldn't want to be the one tell him all his 465 parts will bolt right up to it. I have an 81 465, 80 465, and 80 250 that i could look at to see if i see anything obvious, but since the 80 and 81 250 frames are a different part number as well, it won't do much good, but the 80 250 was a 6 speed and the 81 was a 5 speed, so the engine cases are different but i don't know about the engine mounting points.

One could also go thru the parts fiche and compare some of the major parts to see if they are the same or not but I don't have the time to do that.
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Russ14
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Russ14 3/2/2019 8:53am
3/2/2019 8:53am
If you look at the description of that part # it’s for the rear upper bracket which is the motor mount from head to frame 23145 is the # for that part 21110 is for frames. That’s a mistake on the web, I have the old microfiche and they are the same part #.
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barnett468
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barnett468 3/2/2019 9:48am
3/2/2019 9:48am
Russ14 wrote:
If you look at the description of that part # it’s for the rear upper bracket which is the motor mount from head to frame 23145...
If you look at the description of that part # it’s for the rear upper bracket which is the motor mount from head to frame 23145 is the # for that part 21110 is for frames. That’s a mistake on the web, I have the old microfiche and they are the same part #.
That figures, my local dealer has the same error in their system also.
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GIwasB4
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GIwasB4 3/2/2019 2:50pm
3/2/2019 2:50pm
Thank you all
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Mbyrne
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Mbyrne 8/24/2025 11:40am
8/24/2025 11:40am

Recently picked up a solid 80 yz465 I plan to rebuild. Need a frame thought because mine was raked for hill clinbing.

riv187
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riv187 8/28/2025 8:18am
8/28/2025 8:18am
Mbyrne wrote:
Recently picked up a solid 80 yz465 I plan to rebuild. Need a frame thought because mine was raked for hill clinbing.

Recently picked up a solid 80 yz465 I plan to rebuild. Need a frame thought because mine was raked for hill clinbing.

I would not hesitate to have a competent TIG welder correct the head angle on your YZ. Look for a sprint car shop,race supply shop and ask them for a local to Iowa chassis repair. Knoxille IA is sprint car capital out there.

 

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