Shifter fork wear question (with pics!)

[pekka]

Hello all,

I recently tore down my engine because of couple of issues 1) small ends are loose and 2) steel chips in oil filter.

One time the cylinder bottom gasket slipped and ended up in the engine. It then found its way to the oil filter. The filter tore apart and the chewed gasket went in to the oil galleries. For some reason I did not open the motor then but just put in new filter and oil and hoped for the best. Then I started finding steel in my filter. When I finally tore the engine apart the only visible wear was at shifter forks and corresponding gear grooves. I also found gasket pieces in the shifter axle oiling holes.

As always. Being cheap ends up costing a lot of money.

Now, I would like your expert opinion on the forks and gears: Are they still usable if the get properly oiled or will they keep grinding?

Worn forks in yellow and good ones in blue:

Thank you,

Pekka

 

[azman857]

Never mind. Wrote too soon.

 

[TwoManyXS1Bs]

Those don't look too bad. Normally would look for 'crooked' wear, like the edge of the shiftfork pads, indicating a bent fork. You could mic the pads' thicknesses, make sure they're within 0.050mm of each other. Also check the gears' fork groove widths, and fit/clearance of fork pads in there. More than 0.10mm may indicate replacement.

You'll also want to inspect the corners of the engagement dogs and slots. Heavy rounding and wear may indicate replacement...

 

[pekka]

Thanks TwoMany! I'll do some measuring. I just hope that the hardening has not worn through. Any idea how "thick" the hardening is in the gears?

The dogs and slots are pretty good. I swapped couple of gears that had spots in the surface hardening from a spare gearbox I had. Should be good now.

Pekka

 

[TwoManyXS1Bs]

... Any idea how "thick" the hardening is in the gears?

Pekka, I haven't a clue. The only indicator of hardness depth I've found was 0.030" (0.75mm) on a valve adjuster tip, in this thread:

http://www.xs650.com/forum/showthread.php?t=41639

If somebody could post up clear/crisp closeups of cracked/broken gear teeth or dogs, might be able to determine the hardening depth by examining the fracture surface...