Weird gearbox sensation...

pjmcburney · Post by **pjmcburney** » Tue Dec 01, 2009 11:27 pm

I'm hoping someone's experienced this before...

As I let the clutch out on my L after coming to a complete stop (using some engine-braking, so putting back-loading on the gearbox) I can feel distinct movement in something before the drive-train takes up properly and I start to move.

I'm thinking it's the play I know I have between the counter-shaft sprocket and its shaft (worn spline), but it feels more substantial than this.

Does anyone have an idea as to why it's happening, I sincerely hope it's not an issue with the gearbox itself as I'm not looking forward to splitting the cases.
Could I have clutch-basket wear issues?

Thanks
Paul

Post by **Suzsmokeyallan** » Tue Dec 01, 2009 11:47 pm

Paul id suggest you have a look at the engine sprocket and its splines on the output shaft first. Also perform a check on the rear cush drive rubbers in the hub.
If those are ok, id pull the clutch cover and inspect the outer basket, clutch plates and the inner basket locknut.
If these three items are ok you will need to look further.

Suzukidave · Post by **Suzukidave** » Wed Dec 02, 2009 5:35 am

Its been some time ago but a GTer had the splines wear thru on the sprocket from it being loose and it would just spin on the shaft and no go .. it took some guessing to figure out that one as with the big nut on everything looked fine so its worth checking.

pjmcburney · Post by **pjmcburney** » Wed Dec 02, 2009 3:26 pm

Dave,

I know I've got significant wear on my counter (output) shaft splines.

The sprocket nut comes loose with monotonous regularity - I have a box full of lock-washers and I'm going through them pretty quick. I've got the nut as tight as I dare, but it still manages to work it's way loose fairly quickly and every time I check the splines, they get a little worse.

The overrun characteristics of GT's don't help much either. The surging (although mine is minimal after the air-jet mod) changing the direction of forces on the shaft all the time is likely contributing to the problem.

Eventually I'm going to have to split the cases just to replace the output shaft

.
Might be the perfect time to slot in a GS 'box...

I'll pull the clutch cover on the weekend and check the clutch nut and basket and see if there's any drama there as well

.

Thanks
Paul

rbond · Post by **rbond** » Thu Dec 03, 2009 2:50 pm

I don't know if it is available in Oz land, but I have used Permatex No.2 as a weak threadlocker. So far on anything I have put it on stays tight until I break it loose. It usually lets go without too much extra effort.

Cliff · Post by **Cliff** » Thu Dec 03, 2009 9:41 pm

Make sure your rear sprocket is tight and check the torque rod for any play.

tz375 · Post by **tz375** » Thu Dec 03, 2009 10:28 pm

Paul

The guys covered all the basics. With those thrust reversals, there's a high probability of excess wear in the sprocket and outupt shaft plus the rear cush rubbers are probably worn.

With wear there's slop and that causes things to wear faster and so it goes.

I'd get that GS trans on order with a new sprocket and cush rubbers, so that you are ready to plunge in.

It's always possible that the springs in your clutch drum are completely shagged out too. They wear and damage the back of the basket, so check for free play there too.

ja-moo · Post by **ja-moo** » Thu Dec 03, 2009 11:34 pm

It shouldn't be too hard to shim up the clearance between the sprocket and shaft.........

Craig380 · Post by **Craig380** » Fri Dec 04, 2009 3:09 am

Another possibility: could the clutch center nut be slightly loose?

When I got my 380 it had a similar backlash / taking up the slack feeling from the tranny on setting off. It felt like the trans on a Honda CB400-4, if you know what I mean

Then the clutch started slipping a little under high load in the higher gears, especially after going over a bump on the road. So I ordered up a set of plates & springs.

When I took the clutch cover off, the center nut wasn't even finger-tight

The tab washer was JUST barely holding onto a corner of the nut (it hadn't been bent over properly), and had obviously allowed the nut to turn under high load. This might be worth a quick look one of these winter nights ...

Post by **Suzsmokeyallan** » Fri Dec 04, 2009 6:34 am

Paul if you are soon going to be starting your search for a GS gearbox thats been converted to fit into a GT set of cases just let me know.

pjmcburney · Post by **pjmcburney** » Fri Dec 04, 2009 6:08 pm

Suzsmokeyallan wrote:Paul if you are soon going to be starting your search for a GS gearbox thats been converted to fit into a GT set of cases just let me know.

Hi Allan,

Actually I have a GS 'box, bought it off eBay about six months ago. It's in really great condition, much better than any of the GT 'boxes I have.

I've read the GS 'box thread and Suzukidave's and Teazer's research into the swap - mighty impressive!

I've looked at how it fits - it's not that much work, but it's beyond my workshop capabilities.

I've asked around a bit here in Brisbane, and there aren't too many people willing (or able it seems) to do the mods to make it fit into GT cases.

Perhaps you and I can come to some sort of arrangement...

Some sort of fiduciary remunerative swap a 'box for a 'box maybe? PM me if you like.

In the meantime, looks like I'll be checking those countershaft and clutch nuts...

Thanks
Paul

Post by **Suzsmokeyallan** » Fri Dec 04, 2009 6:52 pm

PM sent to you Paul