2ND Gear Repair

[stanG]

Now I know what you guys are talking about when you say you "miss" second gear. I just finished doing the second gear repair on my 83 and wow, it's a real treat being able to get on the throttle hard in second without having to worry about it popping out even under mild acceleration. All in all the repair went well but I do admit I was a bit baffled when I had the engine ready to come out and just could not figure out which direction it needed to go to get out of the frame. After considerable trial and error, I found that the front of the engine has to come up and then forward to clear the output shaft all while giving it a twist to the right. Likewise, going back in, the procedure in reverse worked great.

 

Once on the bench the cases split apart nicely and the problem was the worn thrust washers. While I had it opened up took advange of all the recommendations on this site and replaced all the o-rings and seals that had been breached and I had the gears undercut to prevent slippage under load. Naturally, I replaced the thrust washers, the washer that goes behind them and shift fork #1. While I was not sure that my shift fork was bent, I replaced it anyway and I noticed that the new one was a beefier design. The parts, including all the gaskets came to about $175.00. I also installed the clutch kit from Skydoc_17 while I had it open, another $70.00

 

Reassembly was cut and dry with the only tricky part being the application of the Yamabond sealant and getting the shifting forks to line up when mating the cases. Once the engine was back in the frame (remember, go in high) I completed the installation and fired it up. After assuring that there were no leaks and everything was up to operating temperature, I took it for a quick spin and the gears worked perfectly. Thanks to all on this site for their wealth of information, help and support. I've added some photos from the build.

 

1. New thrust washers installed

2. Shift fork #1

3. Ready for lower case

4. Ready for lower case

5. Worn out thrust washers

[Dano]

D**n good job Stan. I'm glad you were able to follow the ideas here to get this done. Too bad we're smarter than Yammi mechanics!!

 

 

Better watch pulling the front wheel up after you shift into second!

[Venturous Randy]

Sounds like you done good.

How did you go about undercutting the dogs on the gears? Did you do both 2nd and 5th gear? It is a great feeling to do a job as big as this and for it to turn out ok.

About how many miles did you have on your bike when it started jumping?

RandyA

[stanG]

I had my brother, who is a supervisor at a precision grinding shop, do the gears. He set up a jig to do both 2nd and 5th using a grinding stone and an end mill. The bike had about 55k on it when I bought it as a basket case and it was already skipping. You could use second if you didn't get on it hard. I have pretty much gone through the entire bike now and am confident it will be a good runner this season. I think I am going to look for another basket case for next winter's project.

[icebrrg3rd]

I have heard about this undercutting, and I was wondering if you took before/after pics, or at least an after pic & maybe highlight what was cut. Mine is doing it, but I'm going the way of gears from a '88 to fix my '83.

 

-Andrew

[Venturous Randy]

Well Stan, it sounds like you did it right. I did the undercut thing back in about 98 and think I was about the first one around who did it. I put 60,000 more miles on it and when I ended up with an 86 transmission, I replaced it and have put about 50,000 miles on it.

For anyone interested, there is an 86 trans on ebay right now with about a day and a half left that has an opening bid of $50 and about $14 shipping. It has everything but the outdrive, which I would not worry about.

RandyA

[stanG]

Unfortunately I do not have pics of the undercutting, however there is a thread on this forum that I was able to find.

 

http://www.venturerider.org/forum/showthread.php?t=21023&highlight=undercut