Gearbox output shaft wear..??

[wigs_1]

Right
In the process of replacing the C & S. Bike has done 30k, I bought it at 24k and it already had a scottoiler fitted so they MAY be original.

Anyway, I've removed the C & S and the gearbox output shaft appears slightly more worn than I expected. Old sprocket was a 'rattling good fit', new sprocket is really snug and doesn't move about so I'm tempted to keep progressing with the installation. Anyway, heres some pics.

Output shaft showing wear


Output shaft with new sprocket fitted. I can't help but think it looks a bit 'gappy'


A pic of the old and new sprockets


Also, the locking mechanism holding the front sprocket on looks a bit worn too.


If anyone has any opinions / suggestions on this lot they'd be appreciated.

Cheers

[Wee Bro]

Aaaahhhh, I'm glad someone else feels the same way about thier drive gear as I do. Mine has been worrying me for weeks now and I have ended up placing a shim between the locking ring and the gear to take some of the play out of it. The gear appears to run dry with no source of lubrication other than whats on the chain (hence the wear) so I have ended up greasing mine.I know the centrifugal force will spit most of the grease out but something is better than nothing.

[Opinel]

I have 2 @s, one at 60,000mls, the other at 103,000mls. Each has had the output shaft replaced in its life, either with a first owner or with me. My chain tension was/is perfect (a little bit more than Honda says). I use Scottoilers and EP 80 oil. I use all Honda O/E. I don't thrash the bike. Yet I got this problem.

My latest wheeze will be to make a branch in the Scottoiler and make another feed directly above the front sprocket to drip onto the splines. After lubricating the splines, the centrifugal force should spin it onto the chain. Two in one.(anyone got any comments on this idea, please?)

The wear on my chain and sprockets is much reduced by using this EP80 oil, turned up to give a good flow. This is also intended to let oil dribble down into the splines till I attach my new feed. One chain and sprocket set is now on 30,000 miles plus; if pushed, I estimate there's another 10,000miles there, but I may change it all before that.

I've thought a lot about this problem and if I was still in engineering I would get the front sprocket heat treated in the centre to make it softer than it is -that is, softer than the splined shaft. I believe that the sprocket is too hard. This idea would mean replacing the sprocket more often but that's as it should be. However I dont have access to metallurgists any more so I thought of the extra oil feed to the shaft.



Wigs
-if your new sprocket is snug then go ahead. Even if it were not snug, you have to continue till the output shaft splines are shagged anyway - then replace it at the last gasp. I was lucky - a mechanic friend did it all including shaft and gaskets for £500; plus valve timing and carb balancing thrown in. The shaft costs around £100. Gaskets £70 I think. It's a complete engine strip down, even the gears off shafts etc. It's a big job.

Final thought - I was in France 1000kms from home when my splines gave up and the sprocket spun on the shaft. My temporary "get you home" solution was to weld new splines on the shaft. I mean I formed new splines made of runs/beads of weld. Of course weld metal is softer than tool steel so it was worn out after 1000kms but I got home.

I've heard of folk welding the sprocket onto the shaft and if I were ever buying another @ I would take off the sprocket cover and have a look, as this means of course that the shaft is ruined.

This is the sum of all my knowledge and experience of this problem, which Honda denies exists. I would welcome any comments on what I've written here.

[Opinel]

Aaaahhhh, I'm glad someone else feels the same way about thier drive gear as I do. Mine has been worrying me for weeks now and I have ended up placing a shim between the locking ring and the gear to take some of the play out of it. The gear appears to run dry with no source of lubrication other than whats on the chain (hence the wear) so I have ended up greasing mine.I know the centrifugal force will spit most of the grease out but something is better than nothing.

Wee Bro - the grease melts with the heat. Unless you can find a very high temperature grease -they exist but I dont know where. If you choose this HT grease then let me know where to find it?

[Wee Bro]

Wee Bro - the grease melts with the heat. Unless you can find a very high temperature grease -they exist but I dont know where. If you choose this HT grease then let me know where to find it?

Yep, HT roller and needle bearing grease. Should be available from a half decent motor factor. I like the idea of an oil supply directly to the splines. Nice one.

[wigs_1]

Cheers for the info guys. Think I'll just get it fitted and see how it goes. No motivation here to pull engines from frames, split crankcase / gearboxes etc.

One thought though, why grease the spline ? There are no moving surfaces, in theory it shouldn't move at all. If you don't grease it there should be more friction between the two surfaces and therefore it should move around less. Obviously the sprocket / chain needs a dab of oil.

Cheers

[piguglyshandydrinker]

Right
In the process of replacing the C & S. Bike has done 30k, I bought it at 24k and it already had a scottoiler fitted so they MAY be original.

Anyway, I've removed the C & S and the gearbox output shaft appears slightly more worn than I expected. Old sprocket was a 'rattling good fit', new sprocket is really snug and doesn't move about so I'm tempted to keep progressing with the installation. Anyway, heres some pics.

Output shaft showing wear


Output shaft with new sprocket fitted. I can't help but think it looks a bit 'gappy'


A pic of the old and new sprockets


Also, the locking mechanism holding the front sprocket on looks a bit worn too.


If anyone has any opinions / suggestions on this lot they'd be appreciated.

Cheers

The front sprockets are not original (either the worn one or the new one) as the Honda one has a rubber bush moulded onto it for the chain to run on.
It is still unclear wether non genuine sprockets accelerate shaft wear.

I believe that the most likely cause is too tight a chain. The ammount of people (even very particular owners) that keep an eye on their chain tension and 'do it right' run with too tight a chan.

The only option it to fit everything and keep running 'till it's knackered then either sell the bike to some unsuspecting punter or get the motor stripped.

Looking at the used sprocked, are the sides of the teeth worn or do they just look like it?
If they are, the rear wheel could be out of alignment.

Good luck, Phil

[Lam]

I,ve seen far worst shafts than this.It is a big job to replace so at this stage of it,s life just keep a really good eye on it.

Like the few idea,s given about lubing the front sprocket

And yes have seen welded sprockets,I know of one bought from shop and traded in again (unbelievable but true)

[wigs_1]

sell the bike to some unsuspecting punter

Africa Twin for sale, 6 careless owners, only 30k miles, good runner, new sprockets & gold x-ring chain .........

On a serious note, chain was very tight for one 200 mile journey just before I changed it though I wouldn't have thought that would kill the output shaft. New sprockets are not original, didn't know if the old ones were or not. Its all fitted now anyway, just need to put it through the MOT.

[atgreg]

this is a known prob, for some reason honda uses the xr quick change way to mount the sprocket on both ta's & at's, even new there is play. ive replaced shafts on both. evev running a loose chain doesnt solve it. its a complete engine strip to fit a new shaft, splitting the cases etc.

When my splines got really worn at 150,000km, maybe 20% left i welded a sprocket on did 30,000km, ground it off and welded another one on for another 20,000km. then at 200,000km i did a complete engine rebuild and fitted a new shaft. with a new shaft and guenuine sprocket there was still play, its a stupid system really

wigs, yours isnt bad at all