No power to rear wheel. Not the hub splines. HELP

[tom203]

If you're sure thst you are in 5th and turning the u-joint didn't cause the basket to turn, (and the secondary gear looks OK) something is amiss with either the output from trans (stripped?) or the shock absorbing gizmo has failed somehow. With secondary gear housing out, can you use a mirror and see the coupling (item #3 in parts fiche) ? This is splined to trans shaft and is pushed by spring against gear- it rotates slightly to absorb drivetrain shock

http://www.alpha-sports.com/spst/1981%20GS650GL/45.htm?q=suzuki-parts

here's another pic...

[londonboards]

The clutch outer basket is directly attached to the crankshaft. There is no way you would be able to turn the clutch basket by any means. Even if you took off the clutch cover and had all the plugs removed from the cylinders, you would barely be able to turn the clutch outer basket by hand. Certainly not by engaging 5th gear and turning the back wheel or the universal joint. It would simply be too hard to do. So do not draw any conclusions from that test you made.

On the GS1100G (Which has a different gearbox layout), it is the clutch inner hub that is attached to the front gearbox shaft, which then transmits power (through the appropriate ratio) to the rear gearbox shaft which then powers the bevel gear which turns the shaft drive. In the GS650G, the front gearbox shaft, or main shaft transmits power to the rear gearbox shaft, or lay shaft, and then back up to another section of the main shaft (not connected to the first section of the mainshaft) and to the bevel gear.

In this picture below of the GS1100G (which has the engine upside down) the inner clutch basket is attached where the guy's hand is holding the shaft (as the actress said to the bishop) - the front gearbox shaft.



In this picture you can see the bevel gear at the end of the rear gearbox shaft but the bevel and the secondary bevel has been pulled.

I think most us here would agree that it's highly unlikely that there is a break along either of these shafts or that the bevel gear has stripped. If you can select the gears (as you have indicated because you said you put it in 5th) then I would also suggest that none of the gears in the gear box are stripped. If they were, there would be all kinds of metal bits grinding around that would probably have seized your engine within minutes.

BTW the pics above show a GS1100G engine layout. The GS650G has a slightly different arrangement with it's bevel gear. It is internal to the engine compartment rather than living in it's own chamber, which you can see here. It also has the bevel drive on the front rather than rear shafts:



But the principals are the same. However is does have that spring assembly on the right hand side of the front shaft (number 6 above) which I'm guessing is the drive cushion.

So where is your disconnect? The first thing to say is that if you have ever had an engine out, or even just had the clutch off, you will notice that if you were to spin the front gearbox shaft by hand (labelled 1 in the pic above) and the gearbox is in gear (any gear) there can be almost a quarter of a turn. I have put together a video to try and show it. This is on a GSX1100 / GS1150 EF transmission but it gives you an idea :

The first time I came across this I thought there was a problem with my gearbox. It turns out it is normal. If you add further slack or play from the bevel drives (minimal) and the cushions in the rear drive (if there are any), you might find that you can turn the rear wheel more that a quarter of a turn before it stops (if it is in gear). That amount of slack or play is disconcerting but not unusual. So don't be put off by this.

The only intentional disconnect is the clutch hub, the inner hub slips and does not turn the outer hub (if you are turning the rear wheel whilst it is in geaer) or the other hub turns and the inner hub slips (if the engine is running and the rear wheel is not turning whilst it is in gear).

I have re-read this thread and not found anywhere where you say you have tried to diagnose this problem with the engine running (maybe missed it). What happens when the engine is running and you select a gear and release the clutch? I assume that when you say you "can't get power to the rear wheels" you do have a running engine?

Given all of that, where are the unintentional disconnects? Looking at the GS650 layout, I would suspect that spring loaded cushion device shown in the picture. What would happen if that large spring shattered? I would imagine it would spin with the type of noise you describe. There would also be bits of metal in the whole of the engine, if the broken parts were able to migrate there. I do not know the GS650 set up so I couldn't say. It looks like tom203 has one apart and could tell.

There is also the possibility I mentioned in a previous post that the splines on the secondary gear may have given up (rather than the usual final drive in the rear hub). That would be where 3 meets 4 in the pic below. Or nut 1 has come off and the shaft has snapped at that point.



I don't know if any of that helps. I was just going through it in my own mind to try and figure out what was going on.

I will be very interested to find out what it was. Hope it wasn't a false negative.

[520eek]

I am thinking ...just a guess...but that spring loaded dealio looks like it could be suspect. Once power is applied... the one "gear" (that is backed up by the large short spring) if fractured could cause a problem. You did mention being able to get wheel off the ground a little bit. At that moment..all the weight and forces of the motor are applied to that one little component. That is a lot of energy being applied to a device that perhaps can't take that kind of loading very often....just me thinking out loud...

Anyone else have a thought on this?

[tom203]

"I looked in the oil cap"..... I missed this

better to remove pressure plates and get to bottom of clutch so you can see the big nut holding clutch hub onto shaft as you spin u-joint. My gut stlll says somekind of clutch issue.

[tom203]

Londonboards..

"Certainly not by engaging 5th gear and turning the back wheel or the universal joint"

the 650 trans in fifth is direct drive from clutch to trans ouput shaft - no gears are involved, so he should be able to spin u- joint and see inner basket revolve.

[londonboards]

Tom - I'm guessing that would still be pretty difficult to do as you need to overcome the friction between the two sets of clutch plates - even with the clutch pulled in. Much easier and possible to do by removing inner clutch basket completely and then look at the shaft turning. On my big beasts you can only see the outer basket through the oil filler. I am assuming that if JCP is looking through the oil filler then the case is not off and he won't be able to see the clutch inner hub.

Technically speaking the basket is the outer part of the clutch which is driven from the crankshaft and would still be impossible to turn be hand for the reasons I have already given.

I think?

[jpalm1985]

New Update

Hey guys thanks for all the help. My name is Joe and JChaplick asked me to give him a hand on the bike. Today we removed the secondary gear and it is good. we reinstalled it without the driveshaft on, in fifth gear, with the clutch engaged we were able to spin the secondary using the flange, while doing this we watched the nut and shaft on the secondary and they spun with the flange as they should. We also watched the clutch basket and pressure plate through the oil fill hole and there was no movement. So from my logic that leaves the spring loaded output shaft, the output shaft to main shaft interface or the input shaft to clutch hub interface, correct? Does anyone have any experience with these areas being trouble? We are going to pull the entire clutch off this weekend to look at the input shaft and rule it out. Does anyone know how the output and mainshaft connect? Thanks for the help!

[tom203]

?.....I am assuming that if JCP is looking through the oil filler then the case is not off and he won't be able to see the clutch inner hub.

?

Yes, i don't think you can see inner hub move unless you have a small inspection mirror. In any event, he should just pull the clutch off , cuz something is wrong.

[tom203]

It's sure nice to have a helper!
Anyway, look at attached pic....
the clutch is on left end, then you have first gear, etc. the gear in extreme right is the reduction gear for gears 1 thru 4 off what I call the layshaft. Next to the reduction gear is second gear, but with a stepped portion on its right side. To achieve fifth gear, second gear is slid to left causing the stepped portion to engage into the reduction gear - this locks up the reduction gear causing it to turn at same speed as clutch.

[tom203]

Here's a pic of the insides of the reduction gear showing where the stepped portion of second gear meshes for fifth.

[londonboards]

Curiouser and curiouser.

Get the clutch case off. Remove the inner hub and see if the shaft turns when you turn the secondary.

I think we are talking a complete engine strip to figure this one out. It doesn't look like you can examine this spring loaded cushion device without splitting the cases.

[matt1100]

I'm not sure what that spring is like on a 650 but on an 1100 that is a stout piece of hardware. Could this be a stripped/ failed clutch hub nut or is that just a bigger GS thing?

[londonboards]

I've trawled this forum for any mention of this spring or the failure thereof, but there is no mention of it.

And Matt, it seems that jchaplick has had the clutch off so he should have seen a lose or stripped clutch nut. I think.

What IS going on with this bike?

[jpalm1985]

Thats for the pictures that helps alot. Yes when we pulled the clutch the first time we inspected the hub nut and washer. The nut was tight and the lock washer was bent over onto one of the nut's flat portions. Also yes on spliting the cases for the spring cusion. In jchap first post a member said he had the output shaft break but the gear was held in position by the spring. This caused the bike to seem to function properly with no load but once he tried to move he got nothing. He split the cases and pulled the spring to find that the shaft sheared in the bearing area so the residual friction gave him a false positive when ops checking it. Our hope is someone may have pulled the entire clutch at one point and during reassembly they misalligned the the dogs between the oil pump gear and the clutch basket. Chances are low so we are prepared to pull the motor this weekend.

[jchaplick21]

Thanks everyone for your help. I really appreciate it. Joe and I are going to completely disassemble the clutch assembly today, and if need be, pull the engine tomorrow. Who knew it was going to be this much of a problem?