What's the story on replacing secondary drive?

[madwoodman58]

OK, I'm back!

My used secondary drive (82 GS1100 GL) has come in and I've read my service manual about 50 times on the section dealing with replacing the secondary drive (drive and driven gear).

I have the entire package, so I need to remove the old drives and install the used one. I'm kind of scared for a couple of reasons.

1) The preloading scares me and I don't have any of the "special tools" that are called for.

2) How in the heck do you modify the shim sets if you are a garage mechanic? Am I supposed to buy 20 shims and keep swapping them out? This goes for the internal and the external shims.

3) Is there a way to check the lash on the gears without a dial caliper? That looks like it's about $120 just for the tool.

4) Where do I get the ink that is needed to get the gear mesh correct?

THis looks liek a really, really complicated procedure. I think I can handle it, but a little coashing would be appreciated.

Thanks
Rick

[Eli69]

i replaced the secondary drive units on my 850 recently. seems to be working. instead of the machinists ink stuff the manual calls for i put my daughter's fingernail polish on the gears, ran them, and checked where the fingernail polish was worn off. an inelegant solution but it seems to have worked. some pictures:



it's hard to see in pix but after a couple shim changes the wear marks seemed to be in the correct part of the gears.



here's a pic of the gear backlash measurement. i scrounged this gadget for free somehow a while back. never used it before. anyway you need to do this so maybe you can beg, borrow or steal one.




hope this helps. good luck.

[madwoodman58]

Thanks! That's a help. How long did it take you to complete the process?

[salty_monk]

I have seen a swift spray of primer work where you used nail polish too...

Harbor freight or Northern tool should have cheaper dial gauges...

Good luck

[Eli69]

I have seen a swift spray of primer work where you used nail polish too...

nail polish is prettier though. don't know how long the job took. it was spread out over a couple weeks. luckily i had other bikes to ride.

[SqDancerLynn1]

Just use the shims that came with your replacement gears When assembled there should be maybe .010-.020 gear backlash

[madwoodman58]

That made sense to me, that the shims would match the set of gears, not the motor casing. But with tolerances so small, anything could throw it off.

[rustybronco]

I use hypoid gear marking compound and had used Kendall blue chassis grease up until I had the proper stuff to mark the gear teeth with.

I'm with Lynn, paint the teeth slap it together with the shims that were in your bike and check the back lash. You don't need get too carried away with checking back lash, what you want is the backlash to be loose enough so the gears won't bind when they heat up and not so loose that they go clank when you rock the driven gear against the drive gear.

Also, check the backlash at 3 or 4 different points along the gear teeth so you don't run into a tight spot in the teeth mating surfaces because of normal machining tolerances. Make sure what you you 'feel' is the actual backlash between the secondary drive and driven gears, not the slop in the transmission.

What you are looking for is the tooth contact to be centered in the middle of the teeth both on the drive and coast sides of the teeth and that there is a little backlash between the two gears but not to much. For some sort of an idea on what you are looking for, look at the faces of the worn gear teeth and you'll see what the tooth contact should look like.

Quit worrying, you'll be fine.

[haztoys]

I have a shim set ..I've repaired a mess of these in my travels ...

[madwoodman58]

I have read in several places here that on the 850, you have to crack the case to get the drives out/in, but that with the 1100 I was not clear. Is that a "feel it as you go" thing? loosen the bolts and try to get it out. If it won't come then pop the case bolts in that corner loose and try again?

Just trying to figure out how hard this may be. The engine is out of the bike and sitting on a rolly cart, so I have easy access to everything.

[haztoys]

Dont dick with it .. Pull the motor, turn it over, and, split the case ... Make two straps to wholed the gears in the upper case so you can set the gears up ...

You can do it the other way and some have ...

Find someone that can drill the end and tap for a big bolt on the old part ..Then bolt the flang on and reuse the old output shaft ...

Was the bike run far on the bad flange ...?

[madwoodman58]

I wouldn't go very far! The flange was stripped.

[DanTheMan]

Prussian blueing (found at any auto parts store) works well for checking backlash on the gears as well. On these gear set-ups it's actually easier than doing a complete differential setup as I've done in my Jeep.

[madwoodman58]

Now it is all back together... but it didn't start!

OK, in the process of swapping out the secondary drive (which really wasn't that hard, but I don't know if it works yet) I also:

1 Installed stainless steel brake lines
2 Changed front fork oil and set levels
3 Changed gear oil in secondary and final drive
4 New disassembled and cleaned everything I could get to outside the engine case
5 Added the hose from the air filter box to the engine (which was not on the bike when I bought it)
6 Replaced the fuel line (this bike has a little conical shaped fuel filter that isn't stock. I left it in place)
7 Replaced the rear wheel spline with a pre-82 black model
8 New oil filter, changed the pan gasket, cleaned out the pan
9 Changed the spark plugs

I got it all back together this evening, tried to start it up and the starter runs but I get no firing, no smoke, no nothing other than the sound you are supposed to here, for a short time, when you push the start button.

Where do I start? The high will be under 60 this weekend and I haven't ridden in two months........HELP! You've all been great so far and I promise to do anything suggested. I've never been here before.

Thanks

[SqDancerLynn1]

Start by removing that fuel filter, check for spark