1983 YZ490 Gear Box Pleaseeee Helpppp Meeee.

Discussion in '2 smokers' started by athomerecords25, Jan 14, 2013.

  1. athomerecords25

    athomerecords25 Banned

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  2. Shocktower

    Shocktower Long timer

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    Where are the shift forks, it just looks neutral to me :ear
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  3. stainlesscycle

    stainlesscycle Long timer

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    put the shift forks/shift selector drum in there and then take a look. it's gotta all be there to hold the gears up...no shift forks, and they gears will foul.
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  4. athomerecords25

    athomerecords25 Banned

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  5. athomerecords25

    athomerecords25 Banned

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    Everything is in there, Selector Drum, Shift Forks, Gears, Everything.
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  6. stainlesscycle

    stainlesscycle Long timer

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    those pics are really dark, hard to tell what's going on. . can you put the shift drum in neutral, and take a look and see what's not mating properly? is the main and lay shaft all the way in - with any shims that may be against the bearings
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  7. athomerecords25

    athomerecords25 Banned

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    I remembered I had an old friend that used to have a 1982 YZ490 some years ago. So he comes over and takes a look at it, and messes with it and gets the gears lined up but now the selector star does not meet the end of the thing on the shifter shaft that turns it (selector star doesn't stick out far enough now).

    He did say that it looks like every gear is brand new and I agree. There is no wear, no gouges, no pits nothing. It looks like the guy that had it before me put in entirely new transmission internals.

    So I ask him what happened to his 1982 Yamaha YZ490? He says he split the cases and couldn't get it back together so he took it to the dump. I wish he would of told me that before I let him start messing around with my Transmission.

    He thinks I should take it to the shop. I know most will agree.Yet...I am going to try to locate my Manual or purchase another one and try to do it all on my own.

    I just want to be riding.
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  8. stainlesscycle

    stainlesscycle Long timer

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    i'm assuming you have the cases back together right? or are you fiddling around with it trying to get it to work not together...?

    so shift selector drum end is not far enough out of the case to meet with selector ratchet? is the shift detent (spring loaded shift position stopper - part #3R4-18140-00-00) lined up properly with the groove on the selector drum - i guess it could be hanging up on drum which binds things up?? - if cases are back together can you manually shift the trans by turning the end of the selector drum by hand? ( you will need to turn output shaft by hand to aid the shifting...)

    is the selector drum firmly and fully inserted in the right side case? the shift detent can get in the way if it's not put in the right place...you may have to pull it back and out of the way when you insert the drum, then let it snap back into the groove..

    i looked at pic - USUALLY i install the shift selector rod/ratchet after the cases are back together - i assume you can do that on this motor - it's just one less thing to dick with when you're trying to get the cases back together...
    #8
  9. FJ_Kevin

    FJ_Kevin Been here awhile

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    These usually go together pretty easy.

    First, are you sure all the gears are in the right order on the shafts?

    You can put them together on the bench to make sure the gears on each shaft mesh with their partners on the other shaft and the shafts are still parallel (boats.net will also list the number of teeth on each gear if you need to check).

    If you are pulling parts from multiple sources be careful about using the correct shift fork in the right place. Any chance a 465 fork from a 5-speed is in there?

    Good luck, let us know how it turns out!
    Kevin
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  10. athomerecords25

    athomerecords25 Banned

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    You may be on to something as my Shift Fork that has a number 2 on it, I believe has 4-5 on the flip side. I will go into the garage and check for sure tomorrow.

    I think I am going to halt on everything until I can order another Manual.
    #10
  11. bluebye

    bluebye Skin it back

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    Threads on the countershaft are DEAD.
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  12. athomerecords25

    athomerecords25 Banned

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    Good eye.
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  13. athomerecords25

    athomerecords25 Banned

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    3R4-18140-00-00
    STOPPER LEVER ASSEMBLY

    One last question before I leave this project alone for a little while. Is the Stopper Lever Assembly supposed to lay slack? Or is it supposed to have tension to it (it has the spring there) or be connected to something?

    Thank You everyone for all of your help.
    #13
  14. stainlesscycle

    stainlesscycle Long timer

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    it needs to have tension on it. it's what stops the barrel from slipping into another gear. it is the positive stop for each gear..
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  15. athomerecords25

    athomerecords25 Banned

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    stainlesscycle,

    I have been seeing your posts and information. I haven't been ignoring them. I am a single father so I get very little online time. I don't really get to type much and then a child needs me.

    From your post earlier. I still have the Bottom End unbuttoned and am messing with it and trying to get everything to work right before I button it all back up, that way I won't have to resplit the cases if I didn't put everything back together correctly.

    What is the Stopper Lever supposed to rest on if anything?

    I don't know if my Shift Fork that has a #2 on the front is supposed to have a 4 5 on the back of it or does that mean it is from a YZ465? The 1983 Yamaha YZ490 is only a 4 Speed. and only has 2 Shift Forks.

    I am so frustrated. I don't get much free time and have been working on this bike for some time. I can now see why my buddy just took his 1982 Yamaha YZ490 to the dump. You get frustrated.
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  16. athomerecords25

    athomerecords25 Banned

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    Okay it says #2 on the front of the Shift Fork and 5 x 6 on the back of the Shift Fork and the Yamaha Dealer confirmed that it is in fact the correct Shift Fork (via the phone).
    #16
  17. athomerecords25

    athomerecords25 Banned

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    And here we go. This was the problem with the Tranny. Once I placed the Stop Lever Assembly End in between the gaps within the Selector Star bam it worked perfectly.

    Now why did the Stop Lever Assembly End slip out from in between the gaps within the Selector Star is the question? Why would the Shift Drum back out far enough for the Stop Lever Assembly End to move from its location?

    Any way I am just glad to to know what the issue is. It took a lot of Detective Work being that I cannot find my Manual anywhere. But now the issue is known.
    #17
  18. stainlesscycle

    stainlesscycle Long timer

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    if the shift drum hung up when you split the case, it would lift up and let the shift stop slap behind it. glad it's fixed. 99.9% of all yamaha dirt transmissions are identical in design (and for that matter most any trans with a shift drum....), just minor changes. never had a 465/490 apart, but it's gotta be the same as all the others...just less gears..
    #18
  19. athomerecords25

    athomerecords25 Banned

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    Thank you sincerely for hanging in there and giving me ideas. Everyone else left like one post and bailed. I truly appreciate your efforts to help me. Not many out there like that anymore. The world is a changing.

    I might go get some Yamaha Bond today and start buttoning her back up then rethreading the Counter Shaft End. I think I have time before Supercross on CBS and then the NFL Playoff Games.
    #19
  20. athomerecords25

    athomerecords25 Banned

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    Everything has been buttoned back together. I am about to get some High Temp case paint and then it goes back into the Bike.
    #20