Gearbox issues

[Jonesy :-)]

Nothing holding you back now, see you in wellington

[BrettS]

Well my theory was wrong, seems the spanner in the works that made the gearbox feel like it wanted to jump through the frame was a uni-joint to middle gear bolt come out and getting chewed up. Oops!
All fixed now and now I'm thinking the other work I did has improved the noise from gearbox to a degree. Seems 1st is only really noisey when clutch is in now???
Just more testing and odd jobs to do like a bloody petcock that has chewed two new rubbers so far and all should be good for the rally.

[BrettS]

Thanks Jeff, my theory on the bits in the oil is that it was old debris I've dislodged swivelling the motor around when I soda blasted it. Mal suggested something similar but was blaming something floating around in the middle drive as that was the only replaced part and it wasn't doing that before.
Kinda makes sense that the gearbox was chewing this bit up as each time it did it it was not as bad as before. That last time it did it I broke fairly hard so maybe that flung a bit of steel up into the gears. I've given it all a good clean out so if it does it again or I find more bits next time I will adjust theory.
The other issues I'm not going to stress about at the moment as I'm pretty sure they have always been there and the Sherman box will keep going for some time yet.
I'm getting closer to pinpointing the issue. Noise is different with clutch in and goes away altogether at slow speeds. It's kinda intreaging, I'm pretty sure someone that knows these boxs will get a fair idea what the problem is once they see what I mean.
I'm hesitant to just strip it down as I'm not confident I'll be able to know a problem if I see it.
I think I can do a video showing the noises while I ride it it should be interesting.
Oh and I've not undercut the dogs or know if it's been done but never have any issue with it jumping out of gear, box feels strong as an ox.

[excess.11]

It may be you are experiencing a bearing issue of sorts ..or contamination of them.....have you located where that  debris in the oil is originating from. Cam chain guides or tensioner ?? .I would check all gearbox and wheel bearings and replace all .....just for the hell of it.... if they are cheap and easy enough to do.
A bad bearing or race will do what you are describing. I see in the vid you roughly check the rotation of some bearings by hand ......you may need to go a little deeper and disassemble them to fully check their condition.
Also.....what are the dogs on the gears like?..... have you undercut them ?..
I wonder what the effect on the bike would be if.........all 3 dogs don t mate evenly due to dremel undercutting.
Feeling a second backlash after deaccelerating could be a tuning / exhaust issue .
Just some thoughts to throw into the mix ....along with maybe primary chain issues???

[BrettS]

All back together, correct bolt for gear cluster and new clutch cup spring washer. Noise in 1st n 4th still there also still have backlash in 5th only.
Can anyone think of common part for 1st n 4th that could be the cause. Noise changes when clutch is in and goes away at slower speeds?

[BrettS]

Another video of gearbox, you can see the bits in sump but not well. Some of those bigger bits are not metal.

[BrettS]

There was a bit of metal in the sump, I'll upload a pic soon.

If I get this problem solved Jeff it will be the first time there is nothing at all wrong with the bike, so hopefully the Rally ride will be uneventful.
The plan is to replace the bodgey bolt with correct one then remove inspect/replace middle gear again. Hopefully then all will be good although it will be hard to believe!!!!

[excess.11]

Brett...me thinks this is a late ploy to take home the hard luck trophy.
I see right through you...you sly devil you.
If the grindings and scrapings are as you say....would it not be a good idea to disassemble the suspected part and look for said wear and tear ?

[steptoe]

how much metal was in the sump when you took it off

[BrettS]

When I first got the bike back on the road with the replacement middle gear it would occasionally make some horrendous noises and vibrations from the middle gear/ gearbox area.
First time it happened I thought the bike was frigged and headed straight for home about a km away. Made it home with no further incident and couldn't find any damage so like the idiot I am I went out again. It did it several times intermittently and for some reason I thought it could be from not engaging gears properly so one day I warmed the bike up just enough and then rode it hard. Didn't do it, took it out on the 80kmh road shitting myself it could lock up and never did it again. Until the other day cruising at about 110kmh and after backing of and braking just a bit harder than usual it had another little chew on some metal with a little jolt here n there. Not as bad as before so it's still there a bit. Maybe it has chewed up almost all of what ever it was?

[Jonesy :-)]

Hey Brett
what do you mean by gearbox wanting to spit its guts out? is it locking up or.................
I'll soon have mine apart so we can compare notes.

[BrettS]

Oh and the gearbox wanting to spit itself all over the road may just be the replacement middle gear was no good. Possibly has something floating around inside?

[BrettS]

Had a chat with Mal and he said this issue can arise when the bolt used on main gearbox shaft bearing is not the correct matching bolt for that model gearbox. Mine suits neither year, just a bodgy bolt
Still not sure which model bolt I need so if anyone has that laying around can you take a pic of it and or sell it to me  

[BrettS]

G'day all, been looking forward to doing an update on the bike with pics but this issue has beaten me to it.
Ever since the bike has been on the road I've had some grinding noise, most evident going slow in car parks n such. You can feel it through the left foot peg. We thought it was a middle gear issue and when I took it out it did seem noisey so I put another in that was sourced from USA.
Bike back together and the noise is still there with an added problem of occasionally wanting to spit the contents of the gearbox all over the road.
That went away shortly after and I narrowed the issues down to 1st and 4th had a coarse noise on de-acceleration, 5th now has a strange backlash that can kick in 2 seconds after normal backlash. 2 and 3 are perfect never had them jump out of gear unless I was a overly slack with gear change.
The other day I was cruising at 110km and backed of while braking slightly quicker than normal and the gearbox had another spit which was pretty scary at that speed but it was only minor.
I've started stripping the gearbox down but hesitant to just keep stripping when everything looks ok and I have no idea what is wrong?