Second gear fix issue: can't remove the countershaft!

[clcorbin]

Gents,

Next Problem!!!

I have spent the last hour trying to remove the silly counter shaft on my 79 F model. The bike is nicely upside down in the shop and wide open so I can work in peace. I have all three shift forks out (and the shaft they go on of course) along with the counter shaft bearing assembly and fifth gear.

I can pull the shaft out far enough the clear it's bearing, but I can't pull it out far enough to clear that "flange" on the inside of the tranny case around the counter shaft bearing. I can't move the shaft to the rear because the kick starter gear/clutch assembly is in the way and I can't push it forward because of the first and second gears on the primary shaft!

Needless to say, I REALLY don't want to apply too much pressure to the counter shaft assembly due to fear of damaging something. What in the world am I doing wrong???

[clcorbin]

Got it! Fourth time was the charm. What a pain. But, it's done. I can definitely see why it had a hard time staying in second. And why first is being a pain as well. It definitely needs some TLC in there.

[Ivan]

My 79 has a kick start, my 81 doesnt. However, the 81 did have the stub shaft and bearing in it. I have no clue why Yamaha decided to leave that in, since it really does absolutely nothing.

Anyway...

After pulling that stub shaft and gear out, its 100% easier to get that countershaft in and out. I have never pulled the kick start mechanism off the 79, so I am not personally accustomed to it, but if you havethe clutch cover off and it looks easy enough, try pulling the kick start mechanism out of the way....next time.

[Bigfoot]

Getting that shaft back in is usually the hardest part. Sometimes it can be a pain getting them out too. When installing the countershaft, I have found that a little gentle persuasion with a rubber mallet is sometimes needed.

Another trick that might come in handy, especially since you have the bike upside down. Take a piece of coathanger or other stiff wire and put that in place of the shift fork shaft. With that, you can put the forks in place when installing the countershaft and it gives you some play. Once the countershaft is in place you can slowly slide the wire out while sliding the shaft in the other side. This also helps prevent dropping the forks into the motor and having to spend time fishing them back out. DAMHIK.

I had problems getting things back together once with the kick start gearing in place. Fought with it for awhile. Then I realized a couple things, I don't plan on kick starting this bike and I don't even have the lever to do so. Took the kick start assembly out and pitched it, problem solved.

[clcorbin]

How did you get the kickstarter shaft out? I removed the retaining clip but still couldn't figure out any way to get the shaft out.

Oh well. It sounds like it CAN be done, even if it is a pain in the butt. At least now I have a general idea of the positioning of the counter shaft assembly to get it to clear everything.

But first, I have to do some grinding tomorrow evening after work.

[clcorbin]

Oh, I DO have the kickstarter and it has been used several times in the past 20 years, especially when the battery is getting weak or the bike has been sitting for way too long (and the battery got ran down...). I would rather keep the kickstarter!

On the bright side, I should only have to do this ONCE...

[CatatonicBug]

How did you get the kickstarter shaft out? I removed the retaining clip but still couldn't figure out any way to get the shaft out.

I may be wrong on this, as I have only worked on one '79 before, but I believe the kick start shaft can only be removed after splitting the cases. It does get in the way a bit when re-assembling, but as Bigfoot said, a rubber mallet on the end of the shaft will help convince it to go back in. That and a considerable amount of wiggling and patience. That coathanger wire idea is a must as well. I use a long screwdriver though.

[Ivan]

On the 81, there were three bolts around the bearing retainer, however, there are no kickstarts on thr 80 and up, so there was just a shaft and a gear there. I have no idea why they even put that in.

I will look up the Clymer manual, and see what it takes to get that kick start mechanism out of the way.

As far as not doing it again, that depends on how hard you ride and how well you did it the first time. If you drink too much on the first attempt and ride hard, you may just end up doing it again. I had to, but I think I had one too many Mike's hard lemonades when I did mine the first time.

So, if you need any help, buy me lots of beers and I am kinds sure we can get it almost right...I think.

[trbig]

Yup... almost positive I remember that you have to split the cases to completely remove the kicker assembly. I remember someone wanting to add one until they found out they'd have to split the cases to do so.

When you Dremmel these gears, you will be cutting through the hardened part of the gear to the softer metal. If you ride really aggressively, you could be back in there in a year or two. If you ride like most sane people, it should last a long time.


Mine made it 2 years, but they were absolutely junk when I removed them after that. Nothing salvageable to work with.


Tod

[Bigfoot]

Nope, didn't have to split the cases so it should go back in without splitting the cases as well. I don't remember how I got it out (there might have been beer involved) but mine is out and I have never split the cases on it. It was causing me some grief while laying on my back trying to get the countershaft back in, so I ripped it out. My 80 MNS has a 79 motor in case anyone was wondering.

[clcorbin]

Thanks for the offer Ivan! Hopefully, I won't have to take you up on it!

As for hardening, is there any reason NOT to spot harden the ground areas of the dogs? You should be able to use a torch to heat the face of the dog up to a dull orange and then dunk the gear into an oil bath to quench it. You wouldn't have as much control this way, but you are not hardening the gear teeth, just the drive dogs.

Ideas?

[trbig]

Hard to say. If done correctly and to the right temps with the correct quenching agent, it should work. If not done quite exactly, they will be brittle and break on you under stress.


Tod

[clcorbin]

If not done quite exactly, they will be brittle and break on you under stress.


Tod

Exactly. That was why I was thinking about heating to a DULL red and quenching in oil. It won't be as hard as heating it hotter and quenching in a salt bath, but it won't be as brittle either. My goal would be to simply get them hard ENOUGH that the gears won't die in a few years. I don't expect them to work as long as stock, but if I could get another 15k miles out of it, I would be happy.

Of course, I'm going back to school to finish up my BSME degree. I should ask around the ME department to see if anyone has access to an induction spot hardening machine.

[trbig]

Yeah, we've been discussing grinding down the dogs and slots, one of the members donated me a set to try it on, (Still haven't done it yet, Ben) then welding hard facing on them like construction companies do to the ripper teeth on track-hoes and the sides of the buckets as well as on rock drills. There has been some concern about it weakening the metal you weld to, but these machines take a beating against hard rock and last a looong time, so I am thinking it should work. After welding, you would grind it back down to ORIGINAL thickness. So.. that is in the works still.

As for your your machine, you won't have any problem getting another 15k out of that grind. I can't tell you how many exactly what I got, but it was @ 2 years worth of HARD riding with the gears used in a couple different motors and I ride anywhere from 20-25k a year.

I spoke with a guy.. that I can't remember the name of for the life of me, but he's a famous knife maker. He said his quenching mix is 1/2 transmission fluid, and 1/2 used motor oil. The used motor oil has much more carbon available to get impregnated into the steel. I have also discussed cryo treating the gears with XSChop. He is currently doing some parts for an old Porsche he's putting a Corvette motor in. We'll see if that makes the steel too brittle.. but it's supposed to line up the carbon molecules even better than a heat/quench does.

Food for thought. Just leaving it alone will get you the mileage you are looking for.

Tod

[jmnjrpa]

You will more than likely have to re-temper them after a complete hardening unless they are case hardened as Tod alluded to. This is the usual case with gears. If so, there is a product called Cassonet (I believe that is the spelling). You will have to heat the gear cherry red and immerse it totally in the product. It's kinda like sand and really stinks while in use.

The problem with heat treating is that it is an exact science. Most steels can only be case hardened. Tool steels have a high carbon content which will harden to the core. Case hardened is at most about 1/16" deep. Case hardened steel does not have to be tempered because the center stays soft keeping it from being brittle. Tool steel on the other hand must be tempered to keep it from acting like a chunk of glass.

If someone wanted their gears to really last long a hard chrome plate would do the trick. You can also buy hard surface rods (welding) and build up the gears then grind to fit.