Gears jumped up a slot?

[CatatonicBug]

I have a rather strange transmission issue. I backed out of my driveway as I normally do in the morning, with the bike in neutral. Clutch in, I tapped the pedal to set the bike into 1st gear, and heard a klunk. It was a klunk I have heard before (think "russian tractor"), and I would not have taken notice except for the next thing.

I let out on the clutch and started to give it gas, and the bike responded as if it was still in neutral! So I lifted the pedal and set it back into neutral (light came on), then I tried again, with the same result. I then lifted the pedal into what would usually be 2nd gear, and the transmission engaged, as if I was in 1st! Not even the slightest bogging like I would expect when starting off from a stop in 2nd gear. I rode around the rest of the day (in town, so I never went above 3rd gear), and everything stayed like this. It's almost as if 1st gear moved into the 2nd gear spot, 2nd gear moved into the 3rd gear spot, and 3rd gear moved into the 4th gear spot.

I took the shift cover off (and spilled oil all over my driveway) and inspected the shift pawl and the pins, and everything appears to function properly. except for the fact that when the drum is rotated into the 1st gear position, the rear wheel is still free to spin.

I plan to take the oil pan off tonight or tomorrow, and dig in there, but I was wondering if anyone has experienced this, or what I might expect when I get in there.

[trbig]

My only guess would be the thick washer the detent pin rides on over on the right side of the shift drum has moved. A circlip holds it in place pic'd here. (Detent pin rides on the thick washer next to it)








But, when it happened to me, it got cocked in there as you can see and I couldn't shift at all.


Hopefully it's something easier than that though like just a bent shift fork?

[DGXSER]

When your shifted into second that is acting like first, is the lines on the shift paw arm and the shift drum lined up?

[trbig]

When your shifted into second that is acting like first, is the lines on the shift paw arm and the shift drum lined up?

Good thinking... Duh on my part. In 2nd, everything in red will line up. The two dots and the two lines.

[trbig]

If those lines don't all line up in 2nd, there's a problem with the detent mechanism I mentioned making the shift drum be not in the correct placement.

[CatatonicBug]

All those marks lined up, but now that I have it apart, the plot thickens. I discovered 3 metal "cubes" in the oil pan that appear to have been sheared off from their original locations! I looked up in the transmission, and inspected all the gears I could see, but could not find anything that was missing these 3 pieces. I took the secondary shaft out, and all the gears on it look perfect, just like I left them after doing the 2nd gear fix. I'm stumped... Any ideas as to where these things came from?

The oil pump is there in the top picture to give a size comparison. The snap ring was also in the oil pan, but it came off the oil pump idle gear.

[rover]

gears

Those cubes look like the three pawls that are on the SIDE of the gear that engages 1st gear. When you shift to 2nd gear, are you sure that 1st gear is engaged, and not 2nd gear? If those cubes ARE from the side of the gear, the one that they broke off from will not drive the trans output while that gear is selected, and the others should work.

[Bigfoot]

By the secondary shaft I assume you are meaning the countershaft?

[DGXSER]

I would go ahead and pull the countershaft out and inspect things from there. They look awful big to be the dogs off the gears. But then again, not much else in there is that big, no teeth from any one gear is that big. So it almost has to be something like Rover described.

[trbig]

Yup.. looks like the dogs off of 4th gear broke off. And broke the circlip to your shift fork shaft.

[CatatonicBug]

By the secondary shaft I assume you are meaning the countershaft?

Yeah. The Countershaft. I sat here and thought for 5 minutes, trying to come up with that word...

The pieces are actually about 1/3 the original size of the dogs on the countershaft gears (mine have been ground down). I already pulled it out and inspected everything. These pieces seem to have little notches in them too. They kinda look like they would be tiny versions of the dogs on the gears on the primary shaft gears, except for the notches.

[CatatonicBug]

Yup.. looks like the dogs off of 4th gear broke off. And broke the circlip to your shift fork shaft.

We have a winner! They sheared off so cleanly, I didn't even notice that!



Anyone have a spare 4th gear?

[Schming]

Bummer

What event would have caused that ?

Check with Andreas for a 4th cog

[DGXSER]

Wow, the bigger question being why did this happen. Hate to see you buying another gear a year or a month from now. How much did you have to grind off it?

[trbig]

I've always wondered about this. I know people that come to a light and shift into neutral, then clunk it into gear when the light turns green. They do this dozens of times a day. One: I don't like that CLUNK.. .Two: If an emergency comes up behind me, I'm already in gear to try to get out of the way.

Anyway.. even with all the first gear clunking we've all done, this is the first time I've heard of this happening. Glad to see that it's not just me that tears stuff up that nobody ever has before!