Why the shift drum starfish washer breaks

[3Phase]

I've had two star washers break. The second time it broke the 5th gear shift pin dropped into the oil pan instead of staying in the shifter cover and I rode around with a hardened metal pin in the oil pan for a while. Today I made a tool to fish the pin out of the oil pan through the side of the engine case, then I took apart the shifter to see if I could find out why the star washer broke.

I found it.

The problem was that the shift pawl shift index pin and the pawl body had been hitting the star washer during shifts. Eventually, the leg of the star washer broke off and the pin it was supposed to be holding fell out.

Here are the pictures. I don't like to link directly to huge image files so these are reduced size for the forum display but you can click any of them to see a larger image:

Example XS1100 shift drum showing the broken star washer and the 5th gear shift pin.






Front side of the XS1100 shift pawl and the back of the pressed shift index pins. It all looks good from this side.






Back side of the XS1100 shift pawl and the front of the index pins. There is wear on the upper pressed index pin and the body of the pawl next to the spring.

The pawl body and pin were catching the leg of the star washer when shifting gears and finally broke off the leg, allowing the 5th gear shift pin to fall out of the shift drum and down into the oil pan.






Special tool with a small magnet to fish the 5th gear shift drum locator pin out of the oil pan.






Press a small magnet into the opening in the end of a large zip-tie and it can be used to fish lost metal pins out of the oil pan without getting snagged or sticking to the transmission gears, the oil pump or oil pickup screen.

[motoman]

Interesting Scott.........what do you do in your spare time? Actually, good info for that tab and pin anyways, definitely something to check before going farther. As for the other tabs/pins, specially if still ridden with jumping in and out of gear, shift fork seems to "hang" on shaft under load and force shaft to left knocking off circlip that retains shaft stationary. Then idler gear drops off, and amazingly still does its job being captured behind stuff. The shaft being kicked to the left at that point cocks the piece that catches the pin that rotates the shaft. Cocking that piece at an angle bends the tab outward and eventually pin vibrates out. Looks like a slick way of getting a pin back. Last one I had come out prior to fixing the tranny ended up in filings in the filter housing bolt......eeeeeekkk. Those little pins are extremely hardened steel, but guess the tranny was a bit tougher.

[3Phase]

Interesting Scott.........what do you do in your spare time?

I just finished helping my brother figure out a problem installing 64 bit Windows 7 Pro on his computer. The installer balked and wouldn't install. Joy....

Actually, good info for that tab and pin anyways, definitely something to check before going farther. As for the other tabs/pins, specially if still ridden with jumping in and out of gear, shift fork seems to "hang" on shaft under load and force shaft to left knocking off circlip that retains shaft stationary. Then idler gear drops off, and amazingly still does its job being captured behind stuff. The shaft being kicked to the left at that point cocks the piece that catches the pin that rotates the shaft. Cocking that piece at an angle bends the tab outward and eventually pin vibrates out. Looks like a slick way of getting a pin back. Last one I had come out prior to fixing the tranny ended up in filings in the filter housing bolt......eeeeeekkk. Those little pins are extremely hardened steel, but guess the tranny was a bit tougher.

I really was not looking forward to dropping the exhaust and the oil pan to find that stupid hardened pin before it got eaten by the transmission and the oil pump so at least something went right today! Needy....

I've seen where losing the clips on the oil pump intermediate gear side of the shaft allows the shaft to move but that didn't happen, I checked all of that this afternoon. When I split the cases a while back to replace the starter clutch I replaced all the old clips with new clips so they wouldn't fall off. They're all present and accounted for and they're in good shape.

The shaft doesn't move and there's no slop so I think the shift pawl was just worn. I installed a spare that looks almost brand new and doesn't have booge marks and dents all over it. I'm making another run out to Arizona tomorrow so I'll see what happens.

Ian Fleming: "The 1st time is happenstance; 2nd time is coincidence; 3rd time is enemy action."