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08 YFZ 450 SE: after engine rebuild, I'm having a transmission issue i can not figure out. engine running perfect, go to shift down into 1st gear, i can hear the shift, i can feel the gears move, but... i let the clutch out, the quad will move about a foot and the rear tires lock up. some times, i won't be able to move the sifter. some times i have to get off and rock it back and forth so i can shift into 2nd. second gear seems to work just fine... shift into 3rd, tires lock up engine stalls. took the engine apart, and noticed some of the notches on gears will hit the notches of the gears next to it... causing everything to stop moving. no damage or wear on any parts inside the engine, none. no marks on the shift forks, yet i can't tell if the forks are good or worn. they look perfect. while the engine is apart, i can line the gears up and spin it all freely. start moving the shift drum, going though the gears for movement and the notches lock up. these should never touch each other. does anyone have any idea what would be allowing these notches to come in contact with other gears? i was told the shift forks may be slightly worn. i was told the force of the gears spinning while the engine was running is what keeps them from touching. either way, my quad still won't move and I've taken this apart 3 times for this one damn issue. its riding season and I'm sick of this just sitting here. i need this forum to help me out... I've asked questions and i have never ben answered.... i need some ideas here... help a brother out.
 

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08 YFZ 450 SE: after engine rebuild, I'm having a transmission issue i can not figure out. engine running perfect, go to shift down into 1st gear, i can hear the shift, i can feel the gears move, but... i let the clutch out, the quad will move about a foot and the rear tires lock up. some times, i won't be able to move the sifter. some times i have to get off and rock it back and forth so i can shift into 2nd. second gear seems to work just fine... shift into 3rd, tires lock up engine stalls. took the engine apart, and noticed some of the notches on gears will hit the notches of the gears next to it... causing everything to stop moving. no damage or wear on any parts inside the engine, none. no marks on the shift forks, yet i can't tell if the forks are good or worn. they look perfect. while the engine is apart, i can line the gears up and spin it all freely. start moving the shift drum, going though the gears for movement and the notches lock up. these should never touch each other. does anyone have any idea what would be allowing these notches to come in contact with other gears? i was told the shift forks may be slightly worn. i was told the force of the gears spinning while the engine was running is what keeps them from touching. either way, my quad still won't move and I've taken this apart 3 times for this one damn issue. its riding season and I'm sick of this just sitting here. i need this forum to help me out... I've asked questions and i have never ben answered.... i need some ideas here... help a brother out.
Sounds to me like it's trying to engage two gears at the same time, causing the binding and locking up.

First thing I would do, is with the engine broken down cases split, I would pull each transmission cluster out and find a diagram like on rocky mountain atv in the OEM parts section, make sure that every washer/bushing/bearing/shim etc is in the correct order. Then make sure all the bearings spin freely and fully pressed into the cases.

After that's all verified, install the transmission and forks, make sure you have the forks in the right order and in the correct slots on the shift drum. Then before putting the two cases together, make sure the transmission spins correctly.

I prefer to begin in neutral and then work my way through the gears with the transmission installed in the clutch side case. That's the easiest way to verify the forks are in correctly. If they are installed correctly, in neutral you can hold the counter shaft still and spin the input shaft. If both shafts are trying to turn in neutral something is assembled wrong.

Good luck and let us know what you find.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

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THANK YOU, for replying. i am breaking her back down now. having you say find neutral leaves me stumped. i have yet to find neutral and have a free spinning shaft. i do use the rocky mountain diagrams, videos and order most parts from them. good company!. ill check in later and let you know what i found. any other advice while i try this again will be appreciated. once again, thank you.....
 

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THANK YOU, for replying. i am breaking her back down now. having you say find neutral leaves me stumped. i have yet to find neutral and have a free spinning shaft. i do use the rocky mountain diagrams, videos and order most parts from them. good company!. ill check in later and let you know what i found. any other advice while i try this again will be appreciated. once again, thank you.....
On the shift star, there will be the two points very close to each other that make a very small pocket, in between the larger pockets. That's the neutral position. Spin the shift star so that the detent is in that little pocket. At that point, all the forks should be holding the gears in a way that will not allow one shaft to spin the other.

I tried to include a picture, it's a banshee shift star but the idea is the same. That little double point little pocket is where neutral is. Make sure the detent is in that pocket and not inside one of the larger ones.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

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BAM. found the issue. at the bottom of the shift drum, there is the small round "tab" that goes into the shifting star. the tab wasn't sticking out far enough to "lock" into the star. so when i would torque the star down, the drum wound not be in its position. from what you guys have said and after putting it back together, you were right... the shift forks could't be in the right position once it was torqued.
i pressed the pin out just a little and made the proper connection. now i can go through the gears and find neutral. thank you all for responding and making me think about what was really going on. thank you!!
 
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