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

TeamPropainTurbo38t
Edited Date/Time 8/10/2018 7:34am
As some of you know I went and decided to rebuild my 05 yz 250 2 stroke. Well, I got the motor back together and in the frame. I replaced every bearing possible as well as crank, and top end. I ripped the trans apart as well. I took everything apart one by one and took pics of EVeRYTHING.....I made sure the drum turned and the gears moved then put the motor back together. Here's my problem. I filled the bottom end with oil , took the plug out and am trying to shift the bike through the gears. Well, it seems like it goes into 1st just fine. Then it feels like it shifts up to 5th and I can feel the countrershaft grab when the shifter is in the up position and it releases(spins freely when I release the shifter. The shift lever will allow the it to go to 5th but the countershaft remains in neutral. The only gear that grabs is first. Where might I look when I tear it down again? I double checked everything with the manual as well......stumped.....I am a mechanic but don't do these very often....Dave
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newmann
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newmann 3/1/2012 7:19pm
3/1/2012 7:19pm
Are you certain it's actually shifting through the gears all the way to 5th? Can you feel the ratcheting mechanism and the detent rollers engage with each shift? And the spring loaded ratcheting pawls, are they in the correct places? Most of the ones I've seen are slotted off to one side for the bucket/spring. If you get them backwards it won't ratchet properly or can bind up. I've never been into a modern YZ250 though so just giving general advise here.

And for anyone splitting apart a 1977 RM125 that has the kickstart return spring inside the center cases, the kickstart gears have punch marks where the line up. Don't line the marks up and the return spring won't be properly tensioned and won't return to the up position properly. How do I know this?? Aaaaarrrrggghhh.
mxtech1
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mxtech1 3/2/2012 5:09am
3/2/2012 5:09am
Newmann is right. You did something wrong the the shift ratchet detent pawls. I can eliminate a problem inside the tranny because it wouldn't shift at all, or the countershaft wouldn't spin, if you put the shifting forks in wrong.

The detent pawls are not ratcheting around the drum and locking themselves on the sides of the drum. This gives a vague feeling at the shifter and feels like you are hitting neutrals. You'll need to pull the right side cover off and see what's going on.
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TeamPropainTurbo38t 3/3/2012 6:26am
3/3/2012 6:26am
newmann wrote:
Are you certain it's actually shifting through the gears all the way to 5th? Can you feel the ratcheting mechanism and the detent rollers engage with...
Are you certain it's actually shifting through the gears all the way to 5th? Can you feel the ratcheting mechanism and the detent rollers engage with each shift? And the spring loaded ratcheting pawls, are they in the correct places? Most of the ones I've seen are slotted off to one side for the bucket/spring. If you get them backwards it won't ratchet properly or can bind up. I've never been into a modern YZ250 though so just giving general advise here.

And for anyone splitting apart a 1977 RM125 that has the kickstart return spring inside the center cases, the kickstart gears have punch marks where the line up. Don't line the marks up and the return spring won't be properly tensioned and won't return to the up position properly. How do I know this?? Aaaaarrrrggghhh.
Ok, here is what it "feels " like it does. I can shift it down (spark plug out and using the kick starter) and it goes into gear....I can click up and find neutral. Then it seems like I can click up 4 more times finding neautral each time though. But, when the lever is held up I feel a little "grab" on the countershaft then when I let the shifter sit in it's "normal" position the countershaft freewheels. And once I click up the 4th time you can feel that it doesn't want to click up again.....so this tells me the drum is hopefully in the right spot.... I'm going to look at it today but I want to read a few more responses beforehand. Someone on motonews seems to thing it make just be in the ratchet mech. Thanks for the help by the way guys. Dave
lumpy790
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lumpy790 3/3/2012 6:59am
3/3/2012 6:59am
are you rocking the back wheel when trying to shift? The trans needs to be moving for the dogs to slide into the detent

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TeamPropainTurbo38t 3/3/2012 7:09am
3/3/2012 7:09am
lumpy790 wrote:
are you rocking the back wheel when trying to shift? The trans needs to be moving for the dogs to slide into the detent
I am going to do that in the next hour or so.......will let you know....thx....dude....
TeamPropainTurbo38t 3/3/2012 8:58am
3/3/2012 8:58am
lumpy790 wrote:
are you rocking the back wheel when trying to shift? The trans needs to be moving for the dogs to slide into the detent
TeamPropainTurbo38t wrote:
I am going to do that in the next hour or so.......will let you know....thx....dude....
Ok, mis diagnosis...I put the swingarm and wheel on. It shifts into first and stays in.....then it will shift into neutral but no other gear.....seems like it will go through each gear but not sure.....when I hold the shifter up it goes into gear and will turn the motor over by spinning the wheel but when I release the ahifter it pops back to a neutral position....thoughts?
newmann
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newmann 3/3/2012 12:59pm
3/3/2012 12:59pm
Did you pull the right outer case and check all the ratcheting mechanism, shift shaft and the install on the ratchet pawls and detent rollers yet?
Craze
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Craze 3/3/2012 1:46pm
3/3/2012 1:46pm
You did use a manual?
TeamPropainTurbo38t 3/3/2012 3:43pm
3/3/2012 3:43pm
newmann wrote:
Did you pull the right outer case and check all the ratcheting mechanism, shift shaft and the install on the ratchet pawls and detent rollers yet?
Yeah, I took a small vid of the ratchet mech in action. It looks like the roller bearing pops into the ratcher detent for first, then sits on top in the notched mark for neutral then drops into detents on the mech for 2, 3, 4 then won't ratchet far enough to drop in the last detent. I'm guessing I'm splitting the cases again.....I'll post the vid in a couple of minutes....
DPR250R
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DPR250R 3/4/2012 5:01pm
3/4/2012 5:01pm
Before splitting the cases-

Take the external shift mechanism apart down to part# 4EW-18185-00-00

Spin the trans by hand and try shifting through the gears by turning the drum.

As stated above it might not be an issue between the cases.
4stroke4DWIN
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4stroke4DWIN 3/4/2012 5:02pm
3/4/2012 5:02pm
On the part of the drum that sticks thru the case that the arm ratchets on did it have a pin? I don't know about the yz but CRF's have a pin that sticks out of the shift drum for that barrel thing to catch in. If that pin fell out than your drum will appear to be ratcheting but its not moving inside the cases. Does that make since? I would pull the stuff in the vid back off and make sure that pin is still in the end of the barrel. Sorry I don't know the exact terms I just know how it all goes together.
TeamPropainTurbo38t 3/4/2012 5:22pm
3/4/2012 5:22pm
4stroke4DWIN wrote:
On the part of the drum that sticks thru the case that the arm ratchets on did it have a pin? I don't know about the...
On the part of the drum that sticks thru the case that the arm ratchets on did it have a pin? I don't know about the yz but CRF's have a pin that sticks out of the shift drum for that barrel thing to catch in. If that pin fell out than your drum will appear to be ratcheting but its not moving inside the cases. Does that make since? I would pull the stuff in the vid back off and make sure that pin is still in the end of the barrel. Sorry I don't know the exact terms I just know how it all goes together.
I will read the manual again tomorrow and inspect this. Thanks again. Will keep you updated....
TeamPropainTurbo38t 3/4/2012 5:35pm
3/4/2012 5:35pm
Hmmmm.....if I am thinking like you are.....there is a pin that sticks out of the end of the shift drum where it goes into the case and it would line up with the ratchet mech. I'll check tomorrow. I do however think that the trans wouldn't pop into and out of gear if this wasn't there.....Dave
TeamPropainTurbo38t 3/12/2012 4:55pm
3/12/2012 4:55pm
Ok, got the cases split today. I double check the gear assemblies. They look ok. Washers/clips/gears in correct positions. I put the two gear sets and shift drum back in according to manual. To me, it seems like when the drum goes counter clockwise it stops just short of the end of the grooves and the "right" fork(the lowest groove on drum) seems tight like it just won't go down the last 1/16th" or so to to make it to the end of the groove. The other forks have "slack" when the drum stops, only the right is tight. When I had the gear shafts out I tried each fork in the case and they seemed to move freely up and down. Any thoughts? Dave
mxtech1
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mxtech1 3/13/2012 5:15am
3/13/2012 5:15am
Are you spinning the the countershaft as you try to rotate the drum?

Sometimes I have an engine that doesn't like to spin/shift freely on the bench but once everything is together it shifts fine.
Jake_Dalley
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Jake_Dalley 11/8/2015 8:23am
11/8/2015 8:23am
Any news on your yz? I think I'm experiencing the same exact problem, I just rebuild my bottom end as well. I was wondering if you ever got to the bottom of the issue?
Steeltiger177 3/10/2016 1:40am
3/10/2016 1:40am
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm 1,000 % positive the shift forks are in the right position. This will be my 3rd time splitting the case.

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DuroTools
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DuroTools 3/10/2016 10:54pm
3/10/2016 10:54pm
Steeltiger177 wrote:
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm...
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm 1,000 % positive the shift forks are in the right position. This will be my 3rd time splitting the case.
Steel Tiger, when you put the shifting gear or cam back on to the shift drum did you make sure it was aligned correctly? There is a small dot on the back that has to be lined up with a hole on the end of the Gear Drum. Some of them aren't very profound so you can put it back together without it being correct and you might not notice it is slightly cockeyed. If not Neutral will be in the wrong place.

As for the original post I would check the gear drum and make sure it isn't warped. Roll it on glass and look for wobble also spin it from the ends and look for wobble. I had a similar issue on a bike I worked on and noticed there was allot of play in the side that doesn't have a bearing where the gear drum end goes into so that was causing it to pivot slightly and since it wasn't straight it wasn't shifting correctly. Also look on the dogs where they lift from and look for shiny spots on both sides. If it's shiny its worn and the slightest wear will cause it not to be able to shift. I had a similar issue and bought a used set off ebay that had all the parts I just talked about and I had to use the new drum with some of my old dogs and some of the used ones and keep swapping until it worked. The new drum had a slightly larger end so it took the play out of the hole on the side that doesn't have a bearing. Maybe the your bike is different in that aspect but hopefully some of this helps.
Steeltiger177 3/11/2016 2:51am
3/11/2016 2:51am
Steeltiger177 wrote:
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm...
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm 1,000 % positive the shift forks are in the right position. This will be my 3rd time splitting the case.
DuroTools wrote:
Steel Tiger, when you put the shifting gear or cam back on to the shift drum did you make sure it was aligned correctly? There is...
Steel Tiger, when you put the shifting gear or cam back on to the shift drum did you make sure it was aligned correctly? There is a small dot on the back that has to be lined up with a hole on the end of the Gear Drum. Some of them aren't very profound so you can put it back together without it being correct and you might not notice it is slightly cockeyed. If not Neutral will be in the wrong place.

As for the original post I would check the gear drum and make sure it isn't warped. Roll it on glass and look for wobble also spin it from the ends and look for wobble. I had a similar issue on a bike I worked on and noticed there was allot of play in the side that doesn't have a bearing where the gear drum end goes into so that was causing it to pivot slightly and since it wasn't straight it wasn't shifting correctly. Also look on the dogs where they lift from and look for shiny spots on both sides. If it's shiny its worn and the slightest wear will cause it not to be able to shift. I had a similar issue and bought a used set off ebay that had all the parts I just talked about and I had to use the new drum with some of my old dogs and some of the used ones and keep swapping until it worked. The new drum had a slightly larger end so it took the play out of the hole on the side that doesn't have a bearing. Maybe the your bike is different in that aspect but hopefully some of this helps.
I did not! Thank you! As soon as I get home today I'm going to make sure it's aligned with that pin on the cam. I will keep you informed on the outcome.
Steeltiger177 3/26/2016 1:47am
3/26/2016 1:47am
Steeltiger177 wrote:
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm...
I'm having a slightly different problem. Can somebody please explain to me how I ended up with 5 gears with nuetral being inbetween 3-4. ??? I'm 1,000 % positive the shift forks are in the right position. This will be my 3rd time splitting the case.
DuroTools wrote:
Steel Tiger, when you put the shifting gear or cam back on to the shift drum did you make sure it was aligned correctly? There is...
Steel Tiger, when you put the shifting gear or cam back on to the shift drum did you make sure it was aligned correctly? There is a small dot on the back that has to be lined up with a hole on the end of the Gear Drum. Some of them aren't very profound so you can put it back together without it being correct and you might not notice it is slightly cockeyed. If not Neutral will be in the wrong place.

As for the original post I would check the gear drum and make sure it isn't warped. Roll it on glass and look for wobble also spin it from the ends and look for wobble. I had a similar issue on a bike I worked on and noticed there was allot of play in the side that doesn't have a bearing where the gear drum end goes into so that was causing it to pivot slightly and since it wasn't straight it wasn't shifting correctly. Also look on the dogs where they lift from and look for shiny spots on both sides. If it's shiny its worn and the slightest wear will cause it not to be able to shift. I had a similar issue and bought a used set off ebay that had all the parts I just talked about and I had to use the new drum with some of my old dogs and some of the used ones and keep swapping until it worked. The new drum had a slightly larger end so it took the play out of the hole on the side that doesn't have a bearing. Maybe the your bike is different in that aspect but hopefully some of this helps.
Well, That was the issue! I put it all back together and fired first kick! I changed the bottom end with a hot rods kit, Changed the top end with a Eddie sanders 325. Thank you so much!

GT712
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GT712 3/8/2018 10:55pm
3/8/2018 10:55pm
Hi There if someone could help me asap i am having the same issue Where on the part above the detent drops in to grooove 1 - 2 - 3 - 4 but when it gets to 5th it gets into a "false Neutral" the wheel sits just shy of the peak to drop into groove 5 , but when stationary a solid click or click twice , will drop it into 5th groove but when riding 1,2,3,4 smooth as butter then 5th not a chance ............ i cant think of what it can be as 1,2,3,4 work amazingly but the detent wheel arm just gets stuck before dropping into the fith cup/slot please if someone could help between the cups on the part above the detent wheel sits just shy of that triagnular peak .....

Kind Regards
DirtDog
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DirtDog 7/11/2018 3:15pm
7/11/2018 3:15pm
I am having a similar problem as SteelTiger177. After engine rebuild, neutral seems to be in the wrong position. Durotools seems to have hit on the problem, but I am still unclear on what exactly needs to be aligned in order to fix the problem. The segment in the picture has a groove that alignes with a pin on the end of the shift cam. Is that what you are referring to? Otherwise, what dot are you talking about that lines up with what hole?
DuroTools
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DuroTools 7/12/2018 10:45am
7/12/2018 10:45am
DirtDog wrote:
I am having a similar problem as SteelTiger177. After engine rebuild, neutral seems to be in the wrong position. Durotools seems to have hit on the...
I am having a similar problem as SteelTiger177. After engine rebuild, neutral seems to be in the wrong position. Durotools seems to have hit on the problem, but I am still unclear on what exactly needs to be aligned in order to fix the problem. The segment in the picture has a groove that alignes with a pin on the end of the shift cam. Is that what you are referring to? Otherwise, what dot are you talking about that lines up with what hole?
Hey in this picture I circled the two areas that need to be aligned. Seems like a no brainer but on some bikes the pins are very shallow so it can be easily missed. Also since no other parts are attached after this, if you don't align them it will just have a slight wobble not usually noticeable but will still work just not correctly or neutral won't be in the right spot so before splitting the cases again check this simple thing.
DirtDog
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DirtDog 7/12/2018 11:51am
7/12/2018 11:51am
Thanks for the reply. I'm pretty sure that I had those two lined up when I reassembled the engine. Does the drum need to be rotated to a certain position by a punch mark on the outside, before the pawl assembly is reinstalled. I am wondering if that is what is not lined up correctly. Even my service manual is not very clear on this, and I cannot find any info online that is helpful.
DuroTools
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DuroTools 7/12/2018 2:46pm
7/12/2018 2:46pm
There are different types of pawls and some there is only one way they go but if you have the "finger" or gear type then the "fingers" need to meet in the middle but I don't think that would cause your issue, check out the video below, it's dragged out but may help. Also as we previously discussed if you did have the pin aligned it's possible that when you went to tighten it to the drum that it rotated off so I would double check and also hold it in place when you tighten it back on.
check this out, it may answer your question, https://www.youtube.com/watch?v=zzJIljltUCI
DirtDog
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DirtDog 7/12/2018 8:28pm
7/12/2018 8:28pm
Why would the pin on the shift drum be so shallow? Could it have been worn down by it being installed a little off alignment? I don't remember it being that shallow when I disassembled and reassembled.
DuroTools
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DuroTools 7/12/2018 8:42pm
7/12/2018 8:42pm
I don't think they need to be very deep because once tightened it won't spin over it but yeah they could make them stick out a bit more, I remember I've had some very shallow ones as well, probably half the size of the one in the picture I posted earlier. Did you get it working right?
DirtDog
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DirtDog 7/20/2018 3:20pm
7/20/2018 3:20pm
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?
Mossy
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Mossy 7/20/2018 4:00pm
7/20/2018 4:00pm
I’m having an issue with a 97 yz125. I had the engine and transmission completely redone by a professional reputable company that I will not name.

Anyways, when I sent it, the transmission would not shift at all, was stuck in 1st gear. I got the engine back and it was perfectly fine for 3 rides, then will not shift up past 2nd gear.

So Neutral, 1st, and 2nd can shift perfectly fine, but 3rd is a no go, it feels like it’s just hitting something that’s stopping it from going into 3rd.

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