The Second Gear Removal Procedure

Important extra information

I just got done doing the second gear fix on my SG. I had been putting it off for a while, as working on a transmission seems rather intimidating. There are a few things I wish I had known before starting, as they would have made the job easier, so I'm sharing them with anyone out there who needs to do the fix.

1. You don't actually need an impact driver.
   The instructions call for an impact driver to remove the clutch nut, and another fastener (I forget which one). If you had removed the engine and split the cases, you would have to use an impact driver because the shaft the fastener is attached to is free to rotate. However, because the transmission is still in the bike, and the bike is in gear, you can just hold down the rear brake lever and use a normal socket driver. Of course, not realizing this ahead of time, I blew about $55 on an impact driver and sockets.
2. Make sure you're really in 4th gear.
   As the instructions state, you need the bike to be in 4th gear, otherwise the shift fork shaft won't come out. I accidentally bumped the bike out of 4th gear when I was taking off the left side cover. If the shift fork shaft isn't coming out pretty easily, try putting the shift mechanism back on and re-shifting into 4th.
3. Taking out the oil pump helps.
   I couldn't get the countershaft out because the oil pump was in the way. I'm not claiming it's impossible to get the countershaft out around the oil pump, but I messed with it for 45 minutes and couldn't get it to go. Finally, disregarding Clymer's admonishment that the oil pump can only be removed with the engine out of the bike, I took off the three allen screws securing the oil pump.

   When re-assembling, I poured some oil into the pump and turned the gear a bit to prime it. Then, when the bike was back together, I ran the starter with the spark plugs disconnected until the oil light turned off, before reconnecting the plugs and starting the bike. In total, it took about 1 minute of starter action for the oil light to turn off, but remember you can damage the starter if you run it for more than 20-30 seconds at a time.

    

4. Try a tungsten-carbide cutter in addition to a diamond grinding bit. As I said above, I'd been putting this off for some time, so my gears were pretty worn. The diamond bit was taking forever to get the dogs into shape, so I used a tungsten-carbide bit to remove material faster, then when it was close to finished, I used the diamond bit to get things nice and smooth.
5. Use the other gears to make sure you're cutting the dogs and slots evenly. Another pair of gears on the countershaft (I forget which ones) use an identical dog/slot interfact to hold together. Since these were still in great shape (not worn) I used these to make sure I was cutting the dogs and slots evenly: after a bit of grinding, I mated the part I was grinding with an un-worn part and made sure the three dogs contacted the three slots equally.
6. You can still buy the gears from Yamaha.
   I was worried that I might mess something up grinding the dogs and slots by hand, so I called my local dealer to see if new gears are available, just in case. The guy quoted me around $160 for both gears (countershaft second and fifth). You could probably do much better at a boneyard, though if the second gear problem is as common as it seems, you may have to look around a bit to find a set in good shape. The guaranteed availability of replacement parts gave me confidence to go ahead with the fix.
7. Getting the shift forks back into place is really hard. I took the countershaft all the way out of the engine, which means I had to get the shift forks back into place. After a lot of time and effort, and one shift fork dropped on my forehead, I wound up putting the shift forks into place before installing the countershaft. Fork number 2 doesn't contact the countershaft, so you can put it into exactly the right place and hold it in by installing the shift fork shaft. Number 1 and 3 *do* contact the countershaft, so I put them into the engine with the correct orientation, but rested them on top of the shift fork shaft to keep them from falling on my forhead (having learned from my previous experience). I put the countershaft in, then removed the shift fork shaft so I could get forks 1 and 3 to correctly contact the countershaft, then re-installed the fork shaft.

I think that's everything. It's been close to 3 weeks, and my second gear is behaving like new.