Onward to new adventures in the gear box

[jurgenkoppen]

Hey all tranny experts

While I already once did the "dremel tool slipping out of first gear repair" on my STD's engine successfully, I am now about to turn my 79 Special upside down to dive below the oilpan (since the bike is upside down).
However, before I dare such expeditions, I hope to equip myself with as much info a possible.
The reason is this: The Special engine does not only slip out of 1st gear about 1in-a 100 times (it never ceases to surprise and scare the **** out of me).
Nay, it also has developed other nasty characteristics such as:
Getting stuck between gears on rare occasions, shifting roughly and grindingly into next higher gear when winding out the previous gear ( which is soooomuch fun, the winding, not the grinding noise which ensues)

So I do know how to Dremel the 1st gear and fix that.
But there are also other causes which I vaguely remember, discussed somewhere here on the forum:
Is my shift fork involved? Has the repair been discribed, and if so where can I find it?
What about Super Dave's comments,( a local mechanic) that the secret to fixing the Yami gearbox is to move a certain big washer's location to the other side of the cog to make sure the dogs are engaging properly.
Any and all comments are so much appreciated, as always.
This forum is just frekkin awesome.......
Jürgen,

[greatnw]

Riding an XS11 in Powell River has got to be good!

I'm on the docket to do exactly the same repair for the first time.

Have read some opinions on the washer fix, too. Looking for the same advice.

[CatatonicBug]

Doing the washer swap is a standard part of the 2nd gear fix. There is a washer on one side of the gear, between the gear and a retaining ring. Just put it on the other side when you reassemble, so the gear presses against the retaining ring directly. This moves the gear just a tiny bit closer to the mating surface.

I don't suggest doing the 2nd gear fix without doing the washer swap at the same time.

[Ken Talbot]

Hey, Jurgen, have a look at this post before you turn it over and rip into your transmission.

JAT

[TopCatGr58]

Okay, I'll bite!

I see where Bug has posted, and already there's disagreement in technique, like opinions about OIL!

I've never been a proponent of the washer swap. The square cut gears dogs/slots are the biggest problem with them rounding off and slipping apart=skipping with wear. Once you do the Dremel undercut, they are slightly dovetail cut, and that angle helps to pull the gears together under stress/accelleration. I have not done the washer swap on any of the bikes that I have fixed the tranny's on, and they have all continued to work just fine without skipping since being undercut. However, YMMV, but the Yamaha Engineers put a washer between the gear and the circlip for a reason.

Your shift fork may be involved if you don't know the history of the 2nd bike, like if the PO held it into position to try to keep it from shifting out/slipping, which can put sever wear on the tangs of the fork where it engages with the gears...aluminum rubbing against spinning hardened steel gears!

I would suggest you go ahead and dress up the 2nd/5th gear dogs/slots while you're in there...hopefully you did on your first repair on your other bike! My first went out, and just a few months later, 2nd fell victim.

The hard shifting/grinding may be due to either improper use/lack of the clutch, or not blipping/dropping the throttle at the opportune time prior to shifting to reduce the engine speed so that the next gear can slow down it's spin to better mesh when shifting into it. There are false neutrals between 4th and 5th having found them myself, and I've heard elsewhere when less than ROBUST shifting efforts are applied.

Also, check the shift pawl alignment marks and adjust accordingly. See manual for info.

T.C.

[3Phase]

Jürgen, it is possible one of the shift forks is worn or bent. Also, the shift forks themselves are numbered, make sure they are in the correct location.

People tend to hit the shifter again, harder, when it doesn't go into gear and they also try to 'hold' the shifter in place so the transmission won't pop out of gear when the gears start to slip. That will eventually wear and bend the shift forks and, possibly, the shift drum.



The washer swap mentioned for 2nd gear is pretty simple:

When you remove 2nd gear from the shaft to make the Dremel repair you will find a washer between the c-clip that holds 2nd gear on the shaft and 2nd gear itself.

When you put 2nd gear back on, put the washer on the shaft first, then the gear, then the c-clip. That will move 2nd gear closer to 5th gear so they'll have a little better engagement; about one washer's worth, actually.

Personally, I don't like a gear rubbing against a c-clip so I got some hardened machine washers from another member here, Yahman, that are roughly half the thickness of the OEM washer (imagine splitting the OEM washer in half width-wise).

The 2nd gear hub is machined down on the side that faces the c-clip, then the thick OEM washer goes onto the shaft before 2nd gear. The new, thin, washer goes between 2nd gear and the c-clip. Voila! 2nd gear is closer to 5th gear and there are washers on both sides of 2nd gear.



There are a lot of tutorials in the Forum Repair section and the Tech Tips section.

A lot of this will become apparent when you have the transmission taken apart but there are pictures so you can understand what you're looking at, what the parts are and how to put them back together.


Have fun!


Regards,

Scott (Holy moly!, everyone beat me to it!)

[DGXSER]

Brighter minds than mine have spoken here already. I will share with you that I have done the gear fix a few times. With and without the washer swap. Both ways seems to fix the problem. Some say you can just do the washer swap and not fix the gears if 2nd is the only issue, but I am with TC, for all the work it takes to pull the gears out and put them back, seems senseless not to dremel the gears while your there.

Also, from experience, it sucks to find your shift forks look like someone took a file to them. I got lucky and a fellow XSive with a parts motor donated the forks form it to me. I also have experienced the false neutral from less than meaningful shifting on more than one occasion.

[jurgenkoppen]

I feel ready to tackle the unit,

thank to all who answered, and for providing the links to the relevant pages.
I will probably do all the tricks you mentioned, hopefullY yahman still has a washer for me. So now I just need a weekend and a half to fill my shop with bike grease once more......Hey its all so entertaining, and fun when it succeeds.

[3Phase]

hopefullY yahman still has a washer for me.

If he doesn't, I have one left over that I didn't use. I don't think it would be a big deal to mail it to Canada but I've thought wrong before!


Regards,

Scott

[jurgenkoppen]

USPS is easy

Scott,
Sending stuff via USPS never seemed to be an issue in the past, I get lots of goodies through ebay from the US.
Only UPS is weird, they alway try to gauge by levying "custom brokerage fees", which is total hooey...
With USPS you just mail it without the BS.
I be glad to send you some doe for shipping, your hussle and the part.
Do you do paypal? Thanks ,Jürgen

[3Phase]

Send me a PM with your address and I'll get it in the mail after I get back from riding today.

The Yamaha gears are tough. The machinist I used had a little difficulty cutting down the 2nd gear hub with his lathe so bring the shaft, the gear, the washers and the c-clip to make sure it all fits back together with enough space for the metal to expand. If it fits too tight it will look really good when it's cold but when everything heats up the oil won't be able to lube gear and the washers and it will bind.


Regards,

Scott

[randy]

While we're on the subject....

No, I don't have tranny problems, but I've seen alot of these DremelFix threads, and more than once I wondered how you control and equalize the amount of material you're removing from all the dogs / slots? I would imagine that if the dogs/slots were not cut equally, you would have less than normal contact (some dogs do, some dogs don't) and a net weakening of the works?

Just trying to broaden my understanding of the process.

[CatatonicBug]

Randy - It's basically a lot of guessing, with the liberal use of a set of calipers. That and repeated test-fits while grinding.

[DGXSER]

When I do the dremel work, I use some of my kids old play-dough as a sort of plasti-gage to check my work. Slide the gears on the shaft, add play-dough and twist together to squeeze the play-dough down. Grind as needed till they all show metal to metal contact.

[motoman]

I kinda did an "improvise" to index and keep same spacing/contact pressure for each dog, and held dremal same angle while gear was held in vise. Ironically, the engagement was fully across the dog and flush on the backside of slot when engaged. Plus like T.C.'s choice didn't particularly care for re-locating the washer. But seems to work either way you choose. If moving washer looks to me the machining of inner face of gear for making a recess for other washer would be best option as 3-Phase stated.