Gearbox Troubles

[Fryupdale]

I have a 1993 (P) Africa Twin and over the last two years have not been able to cure a persistent gear change problem. I dismantled the clutch 18 months ago and cleaned up the (not too bad) grooves in the basket but this did not help. I fitted a newer but secondhand clutch this year but no improvement. The cable adjustment is fine.
The geabox is a nightmare of clunking or banging from 1st to 2nd and 2nd to 3rd but better above that. Going down the box, even from 2nd to 1st is always fine.
Is it the gear selectors or barrel? Is it a known problem? At the moment it is spoiling the pleasure of a great old bike.
Despite the rain I have done 2000 miles this summer but the gearbox ain't going to take this punishment for ever.
Richard

[GSPD750]

I have a 1993 (P) Africa Twin and over the last two years have not been able to cure a persistent gear change problem. I dismantled the clutch 18 months ago and cleaned up the (not too bad) grooves in the basket but this did not help. I fitted a newer but secondhand clutch this year but no improvement. The cable adjustment is fine.
The geabox is a nightmare of clunking or banging from 1st to 2nd and 2nd to 3rd but better above that. Going down the box, even from 2nd to 1st is always fine.
Is it the gear selectors or barrel? Is it a known problem? At the moment it is spoiling the pleasure of a great old bike.
Despite the rain I have done 2000 miles this summer but the gearbox ain't going to take this punishment for ever.
Richard

I'll chime in here. My guess is that something is amiss with the gear selector arm and the cam plate which is attached to the drum.
Regardless, you have to remove your clutch for a closer inspection. Also the oil pump chain and sprocket have to be removed which is minor.
With all that stuff out you can now shift thru the gears and see if anything is hanging up. Item (3) the selector arm in the pic has a claw or pawl on the end that engages the cam item (10). If that is bent or not aligned in any way you will have shifting problems. Also item (6) known as the stopper has a small roller on the end which rides on the cam. If that is not centered perfectly on the cam then that may also cause a problem. The shaft on the selector arm (3) should also be straight for smooth shifting. If your problem does not lie behind your clutch (what you see in the pic) well then...you have a bigger job on your hands.

[cernunos]

Hi,

I have a similar problem. Going through the gears is fine (upward / downward). However if i'm cruising at 100km/h in 4th gear going to neutral is fine but coming back up in 2nd, 3rd is causing a grinding in the gear box (just like when you try to go in the 2nd gear from neutral while stationary without engaging the clutch). Is this a normal behaviour? (Sorry if the question is not in the right place or just POD.. plain old dumb :P)

Best regards,
Alex

[Lumiya]

It could be selectors as in the previous posts but most likely cause is incorrect, old or contaminated oil not allowing the free movement of the gear cog, this means that the gear dogs don't line up or spin up properly causing crunching especially at higher speeds...

Try a few engine flushes with a flush product or even clean cheap oil..If it doesn't help then you might need to strip down the gear shafts and see if there's any problems/wear..etc..

[GSPD750]

Hi,

I have a similar problem. Going through the gears is fine (upward / downward). However if i'm cruising at 100km/h in 4th gear going to neutral is fine but coming back up in 2nd, 3rd is causing a grinding in the gear box (just like when you try to go in the 2nd gear from neutral while stationary without engaging the clutch). Is this a normal behaviour? (Sorry if the question is not in the right place or just POD.. plain old dumb :P)

Best regards,
Alex

See my post #2 and go through the motions. The most it will cost you is a clutch cover gasket which is alot cheaper than splitting the cases in order to investigate the gears. You never mentioned the year and model of your AT and as Kymmy suggested...if it is old and neglected then try flushing it.

[cernunos]

Hi,

Thank you for your fast replies. My Africa Twin is an RD07 model from '93. It seams that the previous owner took care of the bike. The oil is brand new as well. (Changed it twice myself). I'll have an inspection as suggested since as I thought this is not normal.

Again changing the gears is fine. Just changing from neutral to 2nd (and then 3rd) at high speeds is somewhat rough.. (with clutch) pressed.

Thanks,
Alex

[GSPD750]

Hi,

Again changing the gears is fine. Just changing from neutral to 2nd (and then 3rd) at high speeds is somewhat rough.. (with clutch) pressed.

Thanks,
Alex

With the clutch and oil pump removed you can easily have someone shift the selector arm (3) by hand and watch for anything abnormal when you pass through neutral to 2nd.

[lootch67]

Hi,
Again changing the gears is fine. Just changing from neutral to 2nd (and then 3rd) at high speeds is somewhat rough.. (with clutch) pressed.

So you want to put the bike in neutral at high speed and then put it in gear again while still at 80/100km/h? Can't think of a trail style bike that'll enjoy that kinda treatment.

[cernunos]

Yep that would be the kind of "treatment" that I've applied
(.. it is not something I'm doing regularly .. actually until recently never tried it) But i was after a long ride my arms were hurting and also my back (since the handle bar are a little low for me) so I thought of putting the bike in neutral while going without hands (straight road for about 5 mile.. no vehicles or animals in sight .. next time I'll just stop for 10 minutes but now it seamed such a shame to not keep on rolling). All went well except for reengaging the gear box(in the sense that it was really upset with me for trying such an action on it ... and clonked and crunched a little before engaging). Is it because in neutral all other pinions inside the gearbox stop moving?! (I'm not that familiar with motorcycle gearboxes and not a mechanical wizard ... but really keen to learn )

10x for all your help you guys

[Lumiya]

In ANY manual gearbox in neutral the output is being turned by the moving wheel and the engine is turning the input, try to mesh them up together at a mismatched speed will always grind the gears a bit, that's why you have a neutral to allow the input to continue spinning at a reasonable speed so that meshing takes place..

You could rev the engine slightly in neutral first to spin up the input before knocking the gears into place when you pull the clutch in..