Gearbox woes - Diversion 600

[Swim41]

Having problems with the gearbox on my 34'000 mile 600N. I've not ridden it much recently having been using my YBR for most things.

Anyway the gearbox seems to bang and clunk more than it used to. I say 'seems', because being used to the silky change on the YBR box the thunks from the Divvy seem savagely brutal.

I have done the following to try and sort it: new sprocket carrier bearings and rear wheel bearings, cleaned and tensioned chain (have tried varying tightnesses, doesn't seem to make much difference). The oil is of good quality (Silkolene Super4) and changed 1800 miles ago. The clutch is adjusted and appears to work correctly (when on stand, rear wheel does not turn with engine running and clutch pulled in).

Worst changes are 1st to 2nd, and especiallty 2nd into 1st although any changes involving gears 1 to 4 can be pretty violent (I actually find myself wincing and bracing myself when changing between 1st and 2nd and down again). The symptoms are not constant however, sometimes the gears snick in, other times there is a severe bang when engaging I'd estimate this was about 50/50.

Another symptom is when changing down into 2nd or 1st it won't actually make the change immediately, giving a the impression of the gears refusing to engage.

In all doesn't make for an enjoyable ride and I'm thinking of getting rid, which is a shame as these engines do have a reputation for toughness and it's not a bad medium tourer/rally bike. At the moment though, the YBR is much more fun to ride.

Any suggestions? Is this likely to be terminal?

thanks
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Yamaha XJ600N

[el_oso]

i always found that my divvy was quite clunky from 1st to 2nd and vice versa, but smooth in other gears.
this problem may be time to have a look at the gear box unfortunately. selector forks damaged or damaged/worn dogs would be my guess, but i certainly am no expert
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[iooi]

Crush rubbers ?

You have not mentioned these.

Any free play in the front sprocket to indicate a knackered bearing due to chain being too tight.

Is it a new chain, or a old one with a tight spot ?
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Just because my bike was A DIVVY, does not mean i am......

[Swim41]

The crush rubbers appeared in good order when I replaced the rear wheel recently. The chain is in pretty good condition, replaced approx 8k ago and seems OK.

Re: front sprocket - am I looking for sideways play in the shaft?
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Yamaha XJ600N

[Kickstart]

Hi

Can you try something? Put the bike on the centre stand, engine running and in gear. With the back wheel spinning pull the clutch. See if the wheel spins for any length of time (if it stops almost immediately then I would suggest the clutch thrust bearing has failed).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[iooi]

[Swim41]

[Kickstart]

Hi

That probably counts out the thrust bearing.

You have covered most other normal things (assuming the chain is fine)

Is the clutch cable smooth? Same for the throttle cable?

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Swim41]

Control cables are regularly oiled and the clutch cable is newish, seems to operate smoothly. I've also checked for play in the actuator (sorry, not sure of correct term) on the clutch cover, seems OK.

I've just had a look in my notebook and was surprised to see that the chain is 12'000 miles old, which I suppose it quite a lot without a Scottoiler fitted. However seems in reasonable condition, with plenty of adjustment left and is not loose on the rear sprocket. I'll have a closer look at the chain tomorrow.

thanks for your help
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Yamaha XJ600N

[Noxious89123]

Plenty of adjustment left might just mean that it has alot of tight spots. If the tension varies alot between different sections of the chain, then it's probably ready for the bin.

Also, it's called a cush drive, which contains cush drive rubbers, not crush.

https://en.wikipedia.org/wiki/Cush_drive
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[iooi]