Problems shifting....yz250 rebuild....

Paw Paw 271
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Paw Paw 271 7/20/2018 6:44pm
7/20/2018 6:44pm
Check the shifter parts behind the clutch basket.

Paw Paw
DuroTools
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DuroTools 7/23/2018 8:24pm
7/23/2018 8:24pm
What parts did they replace when they rebuilt the transmission?
DuroTools
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DuroTools 7/25/2018 1:51pm
7/25/2018 1:51pm
DirtDog wrote:
After reassembly, bike seems to shift fine. Neutral is in the right spot. However, when the bike is in neutral; if i rev the engine the...
After reassembly, bike seems to shift fine. Neutral is in the right spot. However, when the bike is in neutral; if i rev the engine the bike shifts into gear on its own. What is causing this?
I had the same exact issue after I rebuilt my dads transmission on his yz250f but I forget how I fixed it. I think I just rode it and it stopped doing it eventually and I chalked it up to the oil finally working its way everywhere it needed to be. I'll try to ponder it a bit but let me know if you get it sorted cause you have me curious now. Did you just split the cases to replace the rod or something or did you split them just to repair something in the tranny?
DirtDog
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DirtDog 7/26/2018 6:05am
7/26/2018 6:05am
No tranny rebuild, just a bottom end rebuild. The transmission shifts fine through all 5 gears. It just tries to shift into gear when the bike sits in neutral and I rev the engine a bit. It usually does it at the higher rpms. Sometimes it doesn't do it at all. Pin on shift drum seems very shallow (almost flush). Not sure why, because I don't remember it being that shallow when I reassembled it. Maybe the shift segment that fits over the drum end is slipping a little or something, but after tightening that part it doesn't move much to shift. So not sure how it could slip???

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DirtDog
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DirtDog 7/29/2018 7:19pm
7/29/2018 7:19pm
It seems to be all stemming from the dowel pin coming out of the shift drum on the clutch basket side. The pin seems to have been pushed back inside the hole it is in to the point that it is almost flush with the shift drum. This is making it extremely hard to line up with shifter segment that the shift pawl fits into. The pin doesn't seem to stick out enough to hit the notch on the segment. In turn, I am not able to get neutral in exactly the right spot. In turn, the bike wants to shift into gear when revved. Why did they seem to seat the pin in a hole with no bottom, and allow the pin to be pushed in until it is flush?? How do I get the pin to push back out without splitting the cases again and buying a new shift drum. Suggestions anyone??
Hondas4Life3
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Hondas4Life3 7/29/2018 8:22pm
7/29/2018 8:22pm Edited Date/Time 7/29/2018 8:26pm
If it goes completely flush thats not right. It should stick out maybe 1/8 inch little less. The hole on the back of the piece that bolts onto the drum isn't very deep as you can see. Its easy to get the shift palls in the opposite slots. Also you need to install the selector arm/spring/washer in FIRST then use screwdriver to hold it back and install the piece that bolts onto the drum. Hope this helps.
DuroTools
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DuroTools 7/30/2018 11:57am
7/30/2018 11:57am Edited Date/Time 7/30/2018 12:03pm
DirtDog wrote:
It seems to be all stemming from the dowel pin coming out of the shift drum on the clutch basket side. The pin seems to have...
It seems to be all stemming from the dowel pin coming out of the shift drum on the clutch basket side. The pin seems to have been pushed back inside the hole it is in to the point that it is almost flush with the shift drum. This is making it extremely hard to line up with shifter segment that the shift pawl fits into. The pin doesn't seem to stick out enough to hit the notch on the segment. In turn, I am not able to get neutral in exactly the right spot. In turn, the bike wants to shift into gear when revved. Why did they seem to seat the pin in a hole with no bottom, and allow the pin to be pushed in until it is flush?? How do I get the pin to push back out without splitting the cases again and buying a new shift drum. Suggestions anyone??
You must have pushed it in when you installed it wrong. I have a spare one off an 04 YZ250f and just looked at it and the pin can be pushed back out but like you said you would probably have to split the cases. Maybe you can pull it out? Try an earth magnet or maybe super glue or worst case weld something thin to it and pull it out more then cut off what you glued or welded to it. If super glue doesn't work maybe try Jb weld if you can't weld.
DirtDog
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DirtDog 8/10/2018 7:34am
8/10/2018 7:34am
Finally got this problem resolved. It took some out-of-the-box thinking to figure it out. I did not want to weld or glue something on to pull the dowel pin out if I could possibly avoid it. I tried punching it through from the backside of the break drum, but it was almost impossible to line the punch up with the dowel pin without being able to see it. Finally, I decided to punch it straight through to the inside of the break drum and catch it with a magnet. IT WORKED!!! I didn't have to split the cases at all. After reinserting the dowel pin to the right depth, I was able to assemble everything correctly and It fixed the problem. LESSON LEARNED!!
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pkiczuk
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pkiczuk 8/10/2018 11:11am
8/10/2018 11:11am
Nice work, and creative thinking!

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