Transmission Repair Alternative

[79XS11F]

I would copy and paste Bobs article here but he likely wouldn't like that a lot. In any case Bob says his simple fix dose the trick and he claims that the Trany in his bike is the original and the bike has some real high mileage on it. I don't remember the numbers but they were VERY high.
Some of these fits I am sure do the job and given the sources I would have no issues with carrying out the repairs EXCEPT some of them seem complicated. For me the more complicated the mod is the more likely I would be to get some part of it wrong. I will guess from what I have absorbed so far that most of the rounding off and slopping of the contact points dose not affect "in gear" contact foot print between the dogs and the slots. This that correct?? Or dose all the cutting work need to be exactly the same to make sure all dogs are in full contact once the gear in engaged???
I want to do this right but also do it as simply as possible.
I think I will read VERY closely all the available info this weekend and come to a conclusion.
Rob

[TopCatGr58]

Hey JohnDough,

Sorry I didn't post the link to the tech tip, but if you'll go to the MAIN FORUM page, and scroll down to the tech tips, REPAIRS, TRANNY, the first tech tip has lots of pictures and a few diagrams about the undercutting process!

It's recommended to get the contact surfaces as close as possible so that all three, or 6 involving 1st/4th do make contact simultaneously.

However, I did mine 6 years ago before I got some very precise measuring tools, ie. calipers/micrometers, I essentially eyeballed them, and they have held up just fine, can wheelie even when I don't want to . It has been said that Yamaha overengineered these machines, lots of EXTRA strength in the gear parts, just the engagement angle wasn't right at first!

Rob, the portions that you are regrinding and undercutting ARE the contact surfaces between the dogs of one gear and the slots of the other. The actual SIZE of contact is not changed, that is correct if that is what you meant by footprint. What we are doing with the undercutting is creating an angle that keeps the gears pulling together under force which maximizes the contact area.

Since you are only grinding one surface of the dogs, you can use a caliper to gauge the thickness of each one, and then grind the same amount from each one. Same with the slots, measure the solid metal section between each slot, and again grind the same amount from each slot!
T.C.

[Bill]

This should be added to the Repairs > Transmission forum

TopCatGr58 wrote

Veeeerrrrrrryyyyy Interesting!! Thanks for digging it up!!

This is a very cool find. It should be added to the information in the XS11.com > Repairs > Transmission forum.

XSively,

[JonhDough]

Ok i have been to the repairs section, very nice pictures and very informative explination. But im still a little confused, which one of these repairs is the right one and which one will keep me from having to go back into my transmission any time soon? I would like to ride this bike soon, you guys make these bikes sound like they are really great ones .

[Pat Kelly]

The family is going on vacation this week. I may attempt the 2nd gear fix on my E as it jumps out over 4,000 RPM when using lots of throttle. If I go easy in 2nd it does ok.

[pggg]

Back issues of English Classic and Motorcycle Mechanics issue 178 shows an XS1100 gearbox fix. Also numbers 137 & 138 for an XS1100 F1 race bike, 86 for an XS1100 test ride, 164 for changing XS1100 shims. Cost ya 3 pounds fifty per copy. Here's a link.
http://www.classicissues.com/bissues.asp

[rustybones49801]

OK, now for the stupid question segment....... d0oes the engine/tranny have to come out of the bike for the second gear fix?

[Pat Kelly]

Originally posted by rustybones49801
OK, now for the stupid question segment....... d0oes the engine/tranny have to come out of the bike for the second gear fix?

no

[rustybones49801]

Phew!!!

[GNEPIG]

.. you dont have too, but i like to take the motor/trans out of the frame, it makes it easier to work on. i can remove the motor in about an hour and a half now[ive done it enough]. two hours now after the new Jardine exhaust.

which one of these repairs is the right one and which one will keep me from having to go back into my transmission any time soon?

.. just switching the washer from one side of the 2nd gear to the other will only work if your dogs are in good shape or you are going to put in new parts. and just shimming your drive axle and gears only works if your parts are in good condition or new.
.. but you can use your old parts and reshim your trans if you undercut the dogs and slots first, just like in TCs tech tip.
..thier really is no easy way. the easy way is to sell it and let it be someone elses problem.

[79XS11F]

Originally posted by GNEPIG
.. you dont have too, but i like to take the motor/trans out of the frame, it makes it easier to work on. i can remove the motor in about an hour and a half now[ive done it enough]. two hours now after the new Jardine exhaust.


.. just switching the washer from one side of the 2nd gear to the other will only work if your dogs are in good shape or you are going to put in new parts. and just shimming your drive axle and gears only works if your parts are in good condition or new.
.. but you can use your old parts and reshim your trans if you undercut the dogs and slots first, just like in TCs tech tip.
..thier really is no easy way. the easy way is to sell it and let it be someone elses problem.

Well that part about washer change is OK if trany is in good shape is good to read because the trany of my 1978 backup engine is in very very good shape. There is no visible wear on any of the trany parts at this point in time. In fact the insides of this engine are near pristine. With this being the case I do believe i will do the washer position change, check the free play and close her up. I'm will be lucky if I put 2000 KMs a year on my bike due to being a fair weather rider in CANADA so It will not likely be a big issue for me. In any case if the trany gets tricky I will pull the engine and fix it as necessary. I can get the engine out of my bike in about 1.5 to 2 hours. Peice of cake.
Rob

[Goin Commando]

hhmmm, this is a groovey thread, i wonder if i should try this.

[chevy45412001]

under cutting

under cutting of gears was done mostly by racers for years. they take a SMALL amount of material away from the dog ? of the gear to make it look like a dovetail so when shifting gears it helps to pull the gear into the slot and engage properly. Someone with technical lingo can jump on me if i said this wrong.

[GNEPIG]

.. there are pictures at the top of this thread showing gears spacers and circlips in there original places.