Tranny machining question

FWYT
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3/21/2018 9:20pm Edited Date/Time 3/22/2018 1:00pm
I'm working on a '95 YZ250 project bike. 5th gear was seized up solid on the main shaft. Everything else looks just dandy. Question for you guys that know- just out of curiosity; could a good machine shop turn the main shaft and gear to accept a bronze bushing? Is that even a thing or is that a lame idea? Yes, I'm going to replace it but the thought popped into my head so I just thought I'd ask.



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FWYT
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3/21/2018 9:52pm
To be clear, because when I posted this on my FB page, the fugging idiots couldn't see the part where I said "I am going to replace the parts", so I'll repeat, I'm going to replace the parts. The question was if good machine shop does that sort of stuff and if it works. Obviously, lots of trannys use gears that ride on sleeves/bushings.
kzizok
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Fantasy
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3/21/2018 10:33pm


kb228
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3/22/2018 1:15am
Any machinist CAN do it. As far as it working or not, id use steel bushings as brass is really soft. Youre removing material from a gear to retro fit the bushing which will make the gear weaker. Transmissions that have bushings are designed to work with bushings. IMO it might work but not reliably.
Paw Paw 271
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3/22/2018 5:43am Edited Date/Time 3/22/2018 5:44am
I am not sure this is possible due to the fact that the shaft would have to be turned and that would make the OD smaller than the splined portion of the shaft. That would cause issues with a bushing being able to be fitted to that portion of the shaft as it would have to be pressed on over the spline section that would now be larger OD that the shaft. It may be possible to have it built up in OD and then machined back down to size, all that would cost much more than a new shaft. This will most likely also weaken the shaft. Than you have to also deal with the gear.
I suggest replacing the gear and the shaft.

Paw Paw

The Shop

526
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3/22/2018 8:10am
They would grind it undersize then chrome it and regrind it to size.
FWYT
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3/22/2018 12:57pm
kb228 wrote:
Any machinist CAN do it. As far as it working or not, id use steel bushings as brass is really soft. Youre removing material from a...
Any machinist CAN do it. As far as it working or not, id use steel bushings as brass is really soft. Youre removing material from a gear to retro fit the bushing which will make the gear weaker. Transmissions that have bushings are designed to work with bushings. IMO it might work but not reliably.
That was one of my thoughts.
FWYT
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3/22/2018 12:58pm
I am not sure this is possible due to the fact that the shaft would have to be turned and that would make the OD smaller...
I am not sure this is possible due to the fact that the shaft would have to be turned and that would make the OD smaller than the splined portion of the shaft. That would cause issues with a bushing being able to be fitted to that portion of the shaft as it would have to be pressed on over the spline section that would now be larger OD that the shaft. It may be possible to have it built up in OD and then machined back down to size, all that would cost much more than a new shaft. This will most likely also weaken the shaft. Than you have to also deal with the gear.
I suggest replacing the gear and the shaft.

Paw Paw
Thought about that if it were a repair but if it were a new shaft, the bushing could be made the same I.D. as the gear and slid on in the same manner.

Paw Paw, you are like an encyclopedia! Always enjoy your words of wisdom.
FWYT
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3/22/2018 1:00pm
526 wrote:
They would grind it undersize then chrome it and regrind it to size.
Oh yeah? Hmm! I'm not familiar with the actual tech so that's interesting. Thank you!

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