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Looking for any GS shaft drive indepth experience

Here is a pdf from Basscliff per the "MrZooks syndrome" which you have.
http://members.dslextreme.com/users/storagecliff/images/bevel_gear_shaft_repair_zooks.pdf

...I went withe the "get a machinist to replace with a bolt "route myself seeing as the gears were in good shape . It is presently holding up well 8000 km later.

I think the original construction is flawed so I did not replace with an entire (ebay ) assembly just to have the same thing happen again.
 
My 25yrs of making rivets taught me about the machines that make them...they ran a side and front shaft with bevel gears much like the G models do. {probably why I like them - familiarity}

Making millions of pieces on a given machine {@ 100 to 600 parts per minute / running 20hrs a day}...I rarely saw a broken gear set { it happened with a lost tooth here or there, but maybe once a year on one of 130 machines}. Gear slop...yes {reshim} ...but these type of gear sets can take a decent/easy beating so long as they're lubed properly. To have major slop in this set up means something isn't set correct any more {broken}. I saw a lot of broken shafts on those machines...very few gear issues.
 
"Will see how much more trouble I am in when get the gear unit out, and see the bevel gear."

Hopefully, you have caught this issue early and helical bevel gear set is ok... Those things are tough... Your fitup will never be be as good as when it left japan, but should be adequate with reshimming.
 
Had to take apart a few more things and Got all the engine mounting bolts and rods out.
Jacked the engine up about 3/8s and got the assembly out.

Bevel gears show no sign of bad wear.

xJLthk2.jpg


0ArTkr1.jpg


ANd in recent days have a new development such that I can pursue the "Zooks" modification ( so can reuse the existing bevel gear assembly, and not need to go thru the re-shimming deal).

This forum is great.
I am getting this done and it is way beyond my skill and experience level.

.
 
Anybody have any theory as to the root cause of this failure of the threaded portion of the secondary driven gear breaking off...? I cant really see what forces would be on this, other than maybe heat cycles. My ignorant guess is that maybe when they smack that nut to peen that edge over, maybe that starts some stress fracture or something.
S7SRmF4.jpg
 
Those gears look fine (what I can see). show your wife and impress her!

The driven assembly is torqued (to preload those big taper roller bearings) using that jap screw thread and nut - any weakness in the shaft can lead to this fun. Out of curiosity, how big is shaft diameter?
 
Those gears look fine (what I can see). show your wife and impress her!

The driven assembly is torqued (to preload those big taper roller bearings) using that jap screw thread and nut - any weakness in the shaft can lead to this fun. Out of curiosity, how big is shaft diameter?

Oh, I see, just the stretch from torquing the nut, and whatever any thrust on that.

I did show wife, and annoyed her cuz I interrupted her 10th episode of Frazier today.

Shaft of threaded part is about 1.3cm and the larger part is about 2.5cm (oh, garsch, maybe first time I stated things in metric) (my calipers are metric).
 
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It's an M12 nut.

It's pretty clear that the fracture happened at the very first thread. I think the root cause is that the surface of the splines nearby need to be heat-treated to be pretty hard, but the surface of the threaded part also ends up hardened and brittle. Over time and under stress, it can eventually crack.
 
I am excited that I can now announce the best progress now.

Mr Alan "AMK" has made the Zook repair/modification on my secondary driven bevel gear, so I can reuse it (and not need to do all the measure this, micrometer that, dial indicator yaddi yaddi, adjust shim, blue die check yammer yammer,.....)
I am so thankfull and excited that he could do that. Ain't this site great ! ? !

77FLbsw.jpg


Got the driven gear assembly back together, with new oring and seal (bearings were great).

32QOneS.jpg


Hopefully I can get back at it tommorow evening.
 
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Good for you Redman! Well done AMK! ( list yourself somewhere here! http://www.thegsresources.com/_forum/forumdisplay.php?126-GS-Parts-and-Services)

the shimming is complicated as described alright and if you put it all together as it came apart where the primary and all were not damaged ...but you can see that you want your gear teeth to mesh "fully" yet not too tight as to grind each other to bits .....as I interpreted it, hands-on, you want to check there isn't too much " looseness" or "play" ( properly called "lash"?) before you re-attach to rear wheel, which has its own "lash". The two "lashes " (front and back) add up....
 
Thanks Guys ! THANKS !

Got it all together and out for ride this afternoon. Well, most all together, close enough.
0GIaGhJ.jpg


Yep, this took care of the shuddering on decell that had started this summer.... AND took care of the gear whine/growl/whoodle-whoolde that I have been noticing for last couple years (but could not describe, could not hear if was engine rpm related or road speed related... apparently was neither).

Thanks for the diagnosis.
Thanks for the supplying of parts.
Thanks for the machine work.
Thanks for the instruction.
Thanks for the encouragement.
 
This was a good read.
Way to go Redman
Never had a shaft drive bike probably never will, but
I followed along with seeing how things work(and don't) and how they go together and
learned a lot more than I knew before.
I can totally relate to getting in over your head/comfort level experience & expertise
and when you* get it all back together and it works, you feel like patting yourself on the back.

*with some top notch GSR help...
This place does indeed rock.
 
Glad to hear you're back up and running, Dave!
I admire the the guts it took for you to tackle this for someone who "didn't ever want to see his transmission gears".
Good job.
 
Glad to hear you're back up and running, Dave!
I admire the the guts it took for you to tackle this for someone who "didn't ever want to see his transmission gears".
Good job.

THanks.

I must say that I was at a dead-end more than once. THe advice and encouragment here got me going again.

And your fine service made all the difference between keeping my GK going and it being useless. Or I would have swapped out with another gear set, and the shimming and all that would have been quite questionable.

Dave

PS: I still dont want to ever see any of my transmission gears. THis is as close to transmission gears that I ever want to see.
 
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Took another look at that broken-off-nut .
Oh, Yeah, That had been rattling around in there for some time.
mz5ejTi.jpg




It was the last couple weeks that I noticed the shuttering on decell, and getting more severe quickly.
But the last year and a half, or longer, had been hearing some thing that wasnt quite the gear whine folks had been trying to describe. Was a bit more of a whoodle-whoodle than was a whine. And this repair took care of that too. Man, so much smoother and quiter... now I am back to hearing that airbox vibration/resonance/howl , and of course the various rattles and buzzes of the dern GK fairing.
 

Woohoo !
Great news -
I find it incredible that people; who would be strangers if not for this site, step up and help with no expectations of anything more than a thank you .
And the encouragement and helpful advice given is priceless.
I too have been at my wits end at times working on my 850 -
And then I take a break - ask for advice- get some online help - a text or two - and back at it
until I hit the next stumbling point - lather-rinse-repeat-
AND THEN --!
BAM - the problem is resolved and I am a way better wrench hand than I was before having learned something new today ;)
Ride safe and ride often
 
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