2009 KingQuad 500 Shift forks roller breakage

[RayBoy]

Hey all, 

I’m having a problem trying to solve why my shift fork roller keeps breaking.  I have a 2009 Suzuki King Quad 500 and now, for the second time, one of the shift fork rollers has broken and was causing some transfer issues.  Again, this is the second time this has happened.  I can’t figure out why this would be a recurring problem.  It happened about 4 years ago.  Do the forks rattle in the case enough to eventually break?  The quad doesn’t get a ton of hard use.  Yard work and snow removal in the winter.  I thought it may be because I’ve been pushing snow in high range 4x4 but would that break a roller?

I would sure appreciate any help.

 Thanks

Ray from SK

[wiktoriatopajew]

i had same problem i found these parts on ebay .

[Mech]

That's weird..  In fifty years of working on hundreds of bikes I've only ever seen a couple of those broken. Two is not right.

Well.. I'd guess the roller should be virtually unbreakable in that situation, if it fitted nicely on the pin. The pin would support it fom being distorted no matter how chattery or loose in the shift barrel. The pin is the only thing I can see being the cause.

That said..  are those shift forks blue on their ends !! ?  And they are normally built up width ways so only the end of the fork touches the gear. That top gear looks like it's been touching the gear in the arched part of it.   None of that should really cause the roller to break, but it does look like there is some end float or thrust issue going on there.. 

[Gwbarm]

Number 6 shift fork is pretty scarred up , looks like its hitting something causing undo stress on the rollers causing it to break and it is #6 roller that's broken. I would inspect everything very closely on assembling the transmission back together.

[Mech]

Yeah there's something wrong in there..  The forks have a bit built up on their ends so they only contact the gears at opposite sides of the diameter, so the gear will slide nicely. If we tried to slide a gear along by pushing only on one side of it, it would try and jamb on the shaft and not slide. That fork that's touching the gear up in it's arch, shouldn't be.

That fork may be twisted..  the wear looks worse on one arm of the fork..  Where's that eagle eyed Parms.. 

[Gwbarm]

I was thinking that also, being twisted, but its hard to tell, it could be camera distortion.

[RayBoy]

14 hours ago, Mech said:

That's weird..  In fifty years of working on hundreds of bikes I've only ever seen a couple of those broken. Two is not right.

Well.. I'd guess the roller should be virtually unbreakable in that situation, if it fitted nicely on the pin. The pin would support it fom being distorted no matter how chattery or loose in the shift barrel. The pin is the only thing I can see being the cause.

That said..  are those shift forks blue on their ends !! ?  And they are normally built up width ways so only the end of the fork touches the gear. That top gear looks like it's been touching the gear in the arched part of it.   None of that should really cause the roller to break, but it does look like there is some end float or thrust issue going on there.. 

The shift forks don’t appear to be blue on the ends.  
There was noise coming from the motor in high and low range use and I’m not sure if the fork damage came as a result of the broken roller or if it was damaged along with the roller. I suspect if the fork was being damaged for 5 years, it would looks a lot worse.  
 

After the first time this happened about 4-5 years ago, I replaced both forks (which I’m doing again).  

Do you think there’s a problem with the shift drum?   I’m kinda baffled 

[RayBoy]

8 hours ago, Mech said:

Yeah there's something wrong in there..  The forks have a bit built up on their ends so they only contact the gears at opposite sides of the diameter, so the gear will slide nicely. If we tried to slide a gear along by pushing only on one side of it, it would try and jamb on the shaft and not slide. That fork that's touching the gear up in it's arch, shouldn't be.

That fork may be twisted..  the wear looks worse on one arm of the fork..  Where's that eagle eyed Parms.. 

I replaced the forks after the first time the roller broke.  Do you think it would become twisted AFTER it was installed?  I’m not sure if the damage happened before or after the roller broke.  
 

[RayBoy]

I think I’ve figured it out.

I’m missing a spacer.  It looks like it came from the factory that way.  Number 19 in the picture is not there.  So, the roller has constant pressure applied to it when it’s in high or low range,  and over time, the roller breaks.  
 

Any thoughts?
 

 

[Gwbarm]

Wik said he had the same problem, maybe its problematic in those transmissions, if that's the case, damage may have happened after it broke.

[RayBoy]

15 hours ago, Gwbarm said:

I was thinking that also, being twisted, but its hard to tell, it could be camera distortion.

I don’t see any links to eBay.

[Mech]

The only reason I could think of for it breaking was that the pin might have been worn so the roller was being distorted, but a new fork should have cured that after the first roller break. So that idea's out. And I've seen loose rollers..

I wouldn't expect the fork would get twisted in service. I doubt the few small bits of broken roller would cause that wear and roughness on the end of the fork though either. Have you found any other damage, or much metal in the oil ?

Have you done a google search to see if it's a known issue with them ?

The other thing is the fork's end looks rough and worn, and should not be touching up in the center of the arch like that.. That seems suspicious given the problem's on that fork.. Even if there is chattering and perhaps some hard shifting issue that loads the roller up a bit more than intended, it still seems strange that it would break twice. I've been overhauling hondas since 1972 (and all the jap makes), and I've only ever found one or two of those broken. What gears does this shift, or is it a dog it's moving, that is probably important ? Is the shift barrel showing any signs of wear or damage ? Does the gear(if it is a gear) fit on it's shaft nicely ? If the gear was a loose fit on the shaft it could wobble that could cause the wear and the breakage.

Then, if there's nothing over loading the roller, or distorting it, then it comes back to your original question about chatter, and fatigue..  Perhaps assemble the gears and all into one case and turn the shafts gently watching for chatter or wobble. Check the bearings for clicks or bumps. Put the second case on and check the endfloats, including in the shift barrel.

 

[RayBoy]

2 hours ago, Mech said:

The only reason I could think of for it breaking was that the pin might have been worn so the roller was being distorted, but a new fork should have cured that after the first roller break. So that idea's out. And I've seen loose rollers..

I wouldn't expect the fork would get twisted in service. I doubt the few small bits of broken roller would cause that wear and roughness on the end of the fork though either. Have you found any other damage, or much metal in the oil ?

Have you done a google search to see if it's a known issue with them ?

The other thing is the fork's end looks rough and worn, and should not be touching up in the center of the arch like that.. That seems suspicious given the problem's on that fork.. Even if there is chattering and perhaps some hard shifting issue that loads the roller up a bit more than intended, it still seems strange that it would break twice. I've been overhauling hondas since 1972 (and all the jap makes), and I've only ever found one or two of those broken. What gears does this shift, or is it a dog it's moving, that is probably important ? Is the shift barrel showing any signs of wear or damage ? Does the gear(if it is a gear) fit on it's shaft nicely ? If the gear was a loose fit on the shaft it could wobble that could cause the wear and the breakage.

Then, if there's nothing over loading the roller, or distorting it, then it comes back to your original question about chatter, and fatigue..  Perhaps assemble the gears and all into one case and turn the shafts gently watching for chatter or wobble. Check the bearings for clicks or bumps. Put the second case on and check the endfloats, including in the shift barrel.

 

I’m not sure if that damage on the fork happens as a result of the broken roller or caused the broken roller.  I am missing a spacer shown below. Number 19 in this pic.   It’s a spacer/lock washer so maybe that the problem?

I sure appreciate the help here.  I’ll assemble things as you suggested but I’m thinking my problem could com from a missing spacer.  
 

Edited May 13, 2023 by RayBoy

[Mech]

Morning.  I'd missed that earlier post with the diagram.

That washer and the one next to it work together to stop that gear 21 and 23 from moving length-ways. They are all cross cut gears though and there really isn't much end thrust; the washers are not doing much. I'm a bit dubious about them alone being the cause.. Once the gear is engaged, the roller should only be being touched if the gear had slid along the shaft a little, but it won't be pressing hard against it, or causing any chattering that could fatigue it..  I don't think anyway.. 

I'm presuming that the fork goes on part 20 ?  I'd check that (20) fit on it's hub, part 21. I'd be checking it can't rock and allow that wear in the arch of the fork. I'd also check the fit of gear 22 on it's hub 23 looking for the same wear that would allow it to rock on it's bush 23. I think that either of those, if they could and were leaning slightly, as they would be to touch the fork, could and would chatter because of the three engaging dogs on part 20.

If 20 was leaning over slightly, or gear 22 was leaning over slightly, then as the shaft and gears rotated the three dogs would force it, with some force, to keep trying to lean the other way once every 180 degrees of rotation. That force could chatter and break a roller..