Shifter fork wear confirmation

[padgett]

Howdy, hunting an issue with my XS2 where it was popping out of 5th gear pretty regularly. I can nudge it back into 5th no issue, but it'd just find its way eventually shifting down to 4th over time.

Tore down and looking for reasons and im looking at the shifter forks. Specifically this middle one responsible for 4/5. Worn down pretty good, just looking for confirmation that this would most likely be a cause. The actual cogs on the transmission look fine and slide and mate well. Detents on the shift rod are strong and deliberate, so im guessing its this. What do you think?

 

[Its been a long time]

To be honest, to my eyes it looks good. Pictures can be misleading sometimes though.

 

[RC4MAN]

Might be shift drum wear or weak detent spring holding drum in position

 

[Jan_P]

Might be shift drum wear or weak detent spring holding drum in position

I was rapping about spring replacement on anther topic
I Also agree it does not look as the shift fork And have not heard about them having much problems on XS 650
Rather thick and not much power
But it can be bent I assume,

I would start with star wheel adjustment and check operation there including springs so it " Clicks " into correct position
more info in link below but please look in a service manual to be found online About the correct settings

And yes I replaced springs there last rebuild

Star-shaped gear selector out of alignment
https://www.xs650.com/threads/star-shaped-gear-selector-out-of-alignment.28174/

 

[padgett]

Might be shift drum wear or weak detent spring holding drum in position

this spring? not the one holding the star wheel right?

I was rapping about spring replacement on anther topic
I Also agree it does not look as the shift fork And have not heard about them having much problems on XS 650
Rather thick and not much power
But it can be bent I assume,

I would start with star wheel adjustment and check operation there including springs so it " Clicks " into correct position
more info in link below but please look in a service manual to be found online About the correct settings

And yes I replaced springs there last rebuild

Star-shaped gear selector out of alignment
https://www.xs650.com/threads/star-shaped-gear-selector-out-of-alignment.28174/

Well it definitely does clunk into gear with authority and takes some effort to move it from gear to gear with my fingers by rotating the star wheel. But I haven't taken the mechanism out to inspect yet so thats next i suppose.
I swear, if it is just the detent pin and spring and i've split the cases on this engine...

 

[vexsed]

That's the detente, the star wheel/shift springs sit behind the clutch.
These definitely channel female energy. The more intimate you get with them the better you know them. Understanding is a different ballgame.

 

[Jan_P]

Did find a link more pictures

https://www.xs650.com/threads/shifter-fork-wear-question-with-pics.44776/

Anything known about mileage +
Could grab the fork end trying to move wobble it in the perpendicular directions try to feel should the hole be worn larger

Still at adjustment and springs .. What I hear is the lower gears that gets the most beating second gear
And no description here on gear wear.

Thinking out loud could order the detente spring and compare new and old

 

[padgett]

Did find a link more pictures

https://www.xs650.com/threads/shifter-fork-wear-question-with-pics.44776/

Anything known about mileage +
Could grab the fork end trying to move wobble it in the perpendicular directions try to feel should the hole be worn larger

Still at adjustment and springs .. What I hear is the lower gears that gets the most beating second gear
And no description here on gear wear.

Thinking out loud could order the detente spring and compare new and old

yes saw that thread and pics, which lead me to believe maybe my forks were worn down. specifically the middle one. Theres really nothing left of my 'pads'

Theres a bit of play but nothing crazy, or nothing that would simulate enough engine vibration to knock a cog to the next gear position.
Milage is high, 24k miles. and im fairly certain this is the first time the bottom end has been opened up. Which is partly the reason i just wanted to get in there and look at things.

I didn't mention the transmission gears mainly because they look fine. Still have all their edges and nothing alarming at all. The 4/5th gear meshing all looks good.

 

[Jim]

On the right side of the shift drum is a star with a disc/arm/spring that goes tight against it. It's not unheard of for the rivet that holds the disc to the arm coming loose. That can allow the drum to rotate enough to fall out of gear. Got some pics of the right side?

 

[Jim]

 

[Jan_P]

OK if pads are worn as a Fact ...I Would most likely look for a replacement ,, Depending on year model they are on e -bay and so
The fault finding and assembly is to far in ... giving a major hassle doing it over again..Should it fail
Man hours and gaskets to replacement,

I am all for reuse and use as long as possible but here is wear and is solid fact
And 24 k miles is also a factor.

 

[Its been a long time]

Checking on Partzilla, there's hardly any OEM gearbox hardware available new. Problem being an eBay shift fork can be as bad or worse than one you have. It's a specialist job, but worn shift forks can be stellite welded and ground back to new condition.

 

[Jan_P]

Yes used parts are used But I have had good experiences in UK and Germany It appears that larger breakers are
professionals It depends of course if it is a rare part .But overall always good and solutions on the problem .
Honest deal accurate descriptions Cant remember a failure.And if I recall right can send it back, If disappointed.
IN the US it appears to be more bikes with low mileages standing rusting.

 

[padgett]

Took the shift drum and forks out, nothing odd there. Put the forks in the transmission and even with the wear shown they slot in super well with really no issue.

Found my smoking gun i think, and lets see if my theory works.
Removing the shift shaft was a real bear, had to actually punch it out with a drift. inspecting it i found some chain-like wear and the protector was pretty gone. But i put it to the side because I wanted to see inside the cases. Pretty sure I can close that book now.

So I have a 17 tooth front and a standard chain. When fitting it i'd spin the rear wheel with everything fitted up and didn't see any clearance issues. But taking it apart obviously that wasn't the case. Sprocket is loose on its home and i can wiggle it front back/side to side. So thats getting replaced.

My theory is, riding in top gear, even though the direction of travel of the chain necessarily wouldn't cause the shift shaft to knock down...probably instances where it would. This is the only thing in the shifting/transmission that is out of place.

 

[gggGary]

My guess is those marks are ancient history, bet you'll also find a crack in the upper case. A skipping chain hits that tang sticking out causing the crack.

Usually a badly worn sprocket letting the chain skip. PS if the crack's not leaking no big deal.
But it's for sure possible a bent shift shaft might keep the 5th gear from engaging fully.
Any chipped or rounded dog corners on the 5th gear set?

 

[padgett]

My guess is those marks are ancient history, bet you'll also find a crack in the upper case. A skipping chain hits that tang sticking out causing the crack.
View attachment 361997
Usually a badly worn sprocket letting the chain skip. PS if the crack's not leaking no big deal.
But it's for sure possible a bent shift shaft might keep the 5th gear from engaging fully.
Any chipped or rounded dog corners on the 5th gear set?

No 5th gear itself seemed fine like all the other gears. Not rounded and still squared. Theres wear but nothing out of the ordinary for a 20k+ mile engine.

Guess i should probably replace the shift shaft too huh? Didn't look visibly bent but they're not expensive.

 

[gggGary]

Easy to check the shaft, roll it on a flat surface with the shift petal end sticking out far from your surface.
Can also be straightened.

 

[Jan_P]

IS that something to factor in
the shiny spot not sure where it is

A picture of the dogs the gears jumping in and out can help. Just to be sure
Here are experienced people here on the forum can see if edges are worn or so

 

[padgett]

IS that something to factor in
the shiny spot not sure where it is

A picture of the dogs the gears jumping in and out can help. Just to be sure
Here are experienced people here on the forum can see if edges are worn or so


View attachment 362009

light reflection. not wear.

 

[gggGary]

Is the wear on the shift fork pads exactly even? Uneven wear might point towards a bent fork.
I can prolly mike a fork or two see if it seems like your's is excessively worn.
Mikes Xs used to sell "overdrive" 5th gears, it was one of the pair with 1 tooth (more IIRC).