Gears grinding

[ATLRIDER]

Hey guys,

I've got a 93' with 6200 miles on it that sat in a garage for about 12yrs.  Cleaned out carbs, new battery, fresh oil/filter.   It starts and runs great.  Problem is it grinds when putting into 1st or 2nd gear from a standstill. Clutch cable/pushrod is adjusted properly.  I pulled the clutch cover off and removed the frictions discs/ plates/springs for inspection.  All was withing spec.  What I didn't do was to check if they were warped at all with a feeler gauge.  Anyways, anyone ever run into this issue? 

Thnx.

[sledge]

Is it in the clutch or the g/box? Does it make the noise when the clutch is pulled in? I am thinking of that little thrust bearing in the basket cover....item 14


If it only does it when 1st or 2nd is actually selected it has to be in the g/box and related to a worn/damaged, bearing/bush/gear.......in which case as I am sure you are aware its major surgery 

[fred]

Double check to make sure your cable and clutch lifter are in adjustment. My bike started doing something like this and it turned out that the clutch lifter (part 24 on the diagram sledge posted) was failing right where the cable attached. It is just a thin bent tab, and one of the sides on my bike was broken, causing the other side to flex and essentially cause a loose cable like problem. Can you actually get the bike in gear while it is stopped? If your clutch isn't doing its job, when you shift into gear the bike will lurch forward and stall...

[ohgood]

edited. oops.

[ATLRIDER]

Is it in the clutch or the g/box? Does it make the noise when the clutch is pulled in? I am thinking of that little thrust bearing in the basket cover....item 14

Grinding is definetly in the gearbox. No unusual sounds when lever pulled in.  The thrust bearing was in great shape.

[ATLRIDER]

Double check to make sure your cable and clutch lifter are in adjustment. My bike started doing something like this and it turned out that the clutch lifter (part 24 on the diagram sledge posted) was failing right where the cable attached. It is just a thin bent tab, and one of the sides on my bike was broken, causing the other side to flex and essentially cause a loose cable like problem. Can you actually get the bike in gear while it is stopped? If your clutch isn't doing its job, when you shift into gear the bike will lurch forward and stall...

The bike goes into gear and doesn't stall.  After getting into gear I'm able to shift up/down through all gears.  Riding in the neighborhood, shifting feels notchy, not slick like it should be.  #24 is worth a second look.
Thnx.

[sledge]

Grinding is definetly in the gearbox. No unusual sounds when lever pulled in.  The thrust bearing was in great shape.
[/quote]

Nurse?? pass the spanners, we have to operate 

[ATLRIDER]

Oh boy, hope not 

[sledge]

Well....lets be realistic, if it was the clutch the noise would be there regardless of which gear was selected, the fact it only happens when 1st or 2nd is selected suggests it has to be further down the drivetrain and can only be a g/box problem, probably a duff bearing or bush or a worn/damaged gear.........but dont worry, I am sure she will pull through 

[The Buddha]

They thunk ... should not grind ...
However, dont freaking rebuild the transmission ... if it does die from this ... just toss that lump out and buy another one.
Cool.
Buddha.

[ivany]

How long have you been riding it since it was garaged, and when did you last change the oil? Sounds like the clutch may not be fully releasing. Have you adjusted the clutch? And does it do this when warm after you've been riding for a while? <20 miles on a GS is not "warm".

[fred]

Also, how are you shifting the bike? It is a constant mesh transmission, so you can't actually grind gears because they are always meshed together and always in motion. You can, however, get a grinding sound out of the dogs if you are shifting with the wrong amount of pressure. If the dogs are too worn or if you keep shifting in a way that causes them to grind, you will eventually wear them too much to stay in gear. Assuming your clutch is OK, they might be making noise because they are already starting to show signs of wear. I would just keep riding the bike until you couldn't stay in gear anymore if I were you, then take the transmission apart and replace the dogs or get a used engine from someone here and use that.

Here is a fun page with animations and everything to help you get a picture of what's going on in there: http://www.gadgetjq.com/transmission.htm

[sledge]

Unlikely to be worn forks/dogs or drum, they tend to cause difficulty engaging gears and dont necessarily generate grinding, metal-on-metal noises when they wear.

This is pic of the two gear clusters from a GS5, the front one is the input, the rear is the output. I replaced them a few years ago because the splines on the O/P shaft had worn to such an extent the sprocket slipped. Not all the gears are in constant mesh with their corresponding shafts, the two gears indicated are, dependent on which ratio is selected free to rotate on the shafts and only become "live" when they move sideways and engage with the adjacent gear via the dogs. Because they need to rotate independently of the shafts they have Phosphur-Bronze bushes in the centers which are lubricated via oilways drilled in the shafts........... I suspect one of these bushes could have failed, possibly due to a blocked oil-way and its this that is causing the grinding noise.



Regardless of opinions what is actually causing it doesnt really matter because you will still have to split the cases to find out and rectify it. Leaving it is not really an option in my book, you have a very low mileage engine and right now the fault is relatively minor and easily repairable.......carry on and it may well become more serious and ultimately wreck the engine.

[The Buddha]

Sledge - Can it not grind if the dogs have burrs or something on the edges that prevent it from slotting in properly ?
It will make a series of rapid fire mrtallic tonk tonk tonk tonk ... and you'd hear it as a Drrrrrrrr with a metallic tang to it.
Cool.
Buddha.

[intergalactic]

Unlikely to be worn forks/dogs or drum, they tend to cause difficulty engaging gears and dont necessarily generate grinding, metal-on-metal noises when they wear.

This is pic of the two gear clusters from a GS5, the front one is the input, the rear is the output. I replaced them a few years ago because the splines on the O/P shaft had worn to such an extent the sprocket slipped. Not all the gears are in constant mesh with their corresponding shafts, the two gears indicated are, dependent on which ratio is selected free to rotate on the shafts and only become "live" when they move sideways and engage with the adjacent gear via the dogs. Because they need to rotate independently of the shafts they have Phosphur-Bronze bushes in the centers which are lubricated via oilways drilled in the shafts........... I suspect one of these bushes could have failed, possibly due to a blocked oil-way and its this that is causing the grinding noise.





Regardless of opinions what is actually causing it doesnt really matter because you will still have to split the cases to find out and rectify it. Leaving it is not really an option in my book, you have a very low mileage engine and right now the fault is relatively minor and easily repairable.......carry on and it may well become more serious and ultimately wreck the engine.

Wait, wait, wait!!! Bronze bushes? Not roller bearings under the gears? That's new. I remember taking apart car transmissions better, but I don't recall bushes/ plain bearings between the gears and the shafts they ride on. Weird. 

[The Buddha]

Muhahahaha ... What part of economy do you not understand.
The F*(ker has nothing but tin foil holding up everything.
If I was building a bike, I'd put roller bearings everywhere. Cranks should come apart and roller bearings in there then rods go on that. Cam shafts, and all transmission etc. Also I'd design a 2 storey engine that the transmission can be removed by taking out the oil pan like a yamaha XS1100. Of course you still have to have dogs and synchro's for engaging them, but all the rest can be roller, and we dont need any oil pressure at all holding the motor alive. Splash lube on all the contact parts - cams and valves, cylinder walls, gear teeth etc, and run through an oil cooler, but that should be it.
Anyway, this crap lasts 40K so I guess they figured we'd lose interest by then, and after that who cares. In fact manufacturers would like nothing better than to screw any one that buys a used anything. They cater to their customer, and would like nothing better than to see us all have dead bikes ... forcing us to buy into their prettied up crap and empty promises of "warranty".
Cool.
Buddha.

[sledge]

Yep......Bushes, part nos 5 and 19.

[sledge]

Sledge - Can it not grind if the dogs have burrs or something on the edges that prevent it from slotting in properly ?
It will make a series of rapid fire mrtallic tonk tonk tonk tonk ... and you'd hear it as a Drrrrrrrr with a metallic tang to it.
Cool.
Buddha.

Buddha?
I guess it all depends on what you interpret as "Grinding noise"....to me it means a nasty metal-on-metal sound. Diagnosing faults from a description of the sound is a killer though. Its like me standing next to you, then dropping my guts and asking you to guess what I had for lunch 

[ATLRIDER]

Well I appreciate everybody's feedback so far.  What gets me is the bike only has 6200 miles.  Just to clarify,I haven't ridden this bike more than a mile or so around the neighborhood.  It's had two oil changes so far and as I recall the first time I rode it shifting was notchy but didn't grind.  Fast forward to the present and have the current problem.

Starting in neutral with light hand pressure on the shift lever without going fully into 1st or 2nd gear, feels like gears are spinning and touching makes a metallic tat-tat-tat sound.  Once in gear the noise is gone and am able to fully run through all the gears.  Only exception is when I shift back into neutral with the clutch still held and shift into either 1st/2nd same sound/grinding occurs.
-Are these the dogs trying to engage into the windows?
-Any chance clutch plates are sticking or going bad after sitting for 12yrs in same oil?

I'd like to exhaust all posibilities b4 taking it apart. 

Thnx

[The Buddha]

That noise @ shifting definetly is dog burr type wear ...
Sledge's defect will be grinding when its in 1st and rolling.
I would ride it and look for a motor ... not at all common on a GS ...
Cool.
Buddha.