As I may have mentioned I killed the gearbox in my R1 engine back in June just over half way through an Alps trip (it was a largely unknown engine so the 'box may have been on the way out anyway)

Been very busy so only just got the engine out yesterday (yes I know!!!)

Knew the box was toast as it was a full throttle clutchless shift from 1st to 2nd or 2nd to 3rd and the horrible sounds it made shortly after very much sounded like hardened metal teeth shearing off and passing through other gears

Just dropped the sump and as expected found a few gearbox teeth (right hand side of photo).

However I'm a bit at loss at to what the other bits are from (left hand side near the tip of the screwdriver).

They are toothed on the *inner* diameter and are curved and smooth on the outside.

I've looked at the replacement gearbox I have (thanks Jim!) and I can't really spot any parts that look like these.

So have I killed something other than the gearbox? Oil pump (it doesn't look like fragments from a trochoid pump though).



I am getting the gearbox rebuilt professionally (would have a go myself but I'm short on time) so no doubt it will be addressed - I'm just curious as to what these chunks are from. If I was rebuilding it myself I would carry on stripping it and find out fairly quickly but as someone else is doing it I don't really want to give them the engine in loads of pieces etc.

The bit on the left is definitely a screwdriver and the other bits looks like the outer edge of a clutch basket,

Goosed..

Rich

I'm fairly sure they aren't clutch basket parts as there aren't any internally tooth parts in the clutch basket as far as I know?

Also the basket itself is mostly aluminium whereas these are definitely steel (magnetic).

Any other guesses? I've stripped (but not rebuilt!) a few R1 engines and I can't remember any bits that looks quite like this!

[Edited on 23/1/11 by hobbsy]

don't know anything about the inside of bike gearboxes, but are they dog ring? is that what they're called?

like this?

I briefly considered that it could be from this but the outside of the "chunk" is smooth and the dog rings are one piece - so it can't have come from that (unless it completely sheared a chunk off the inside and it was some how smooth on the outside?)

It looks like the sprag assembly that fits into the back of the clutch basket

David

Looking at the Yam'manual there's collars on the gear shafts that look like that. Appears the gears fit over them but not clear from the pictures without having the actual bits to compare with.

Adi,

Yeah I vaguely seem to recall that there is something that looks like that which runs on the gearbox shafts (x2). The shaft is externally toothed and so the bits that run on it are internally toothed. I have a 2min glance at the gear clustered after the first reply but I don't think you see them straight away unless you slip all the gears off the shafts and I didn't want to get my drinking hand oily

If its gearbox bits then I'm not too bothered - just worried that it might be from somewhere else and so I would need more bits

Are you keeping the flatshift after all this?

quote:

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Originally posted by adithorp
Looking at the Yam'manual there's collars on the gear shafts that look like that. Appears the gears fit over them but not clear from the pictures without having the actual bits to compare with.

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Flatshift possibly.

Electric (linear actuator) power shifter - maybe not!

Briefly looked at a clever gearbox ECU (GCU!) that considers the angle of the selector drum (so knows for sure when you've made a successful shift) and so cuts the ignition for the right amount of time every time.

http://www.geartronics.co.uk/flatshift.htm

However he wasn't keen on me using my techtronics shifter with his system (he sells a pneumatic shifter with lightweight on board compressor which brings the total price to more like £2k - GCU is only £200+VAT) so have knocked that idea on the head for now. Also needed some fabrication to get the gear selector drum potentiometer in place.

So I've bought a mechanical paddle kit which I'm likely to fit. I always retained the stick shift on the trans tunnel so I can fall back on that if needs be. I did really like the electric paddles while they worked though. My first engine I put about 6k on before I was just starting to loose 3rd (which is what brought about the last minute engine swap in May last year before June's Alps trip).

Somewhere in France while having a few beers on evening...

Hobbsy. "What breaks gearbox's?"
Sevral of us in unison. "YOU DO!"

Ive got mechanical flatshift now, on the paddles. So in doing the shifting but the sensor in the linkage and the box of tricks does cut for me. If you can just ditch the actuator I'd do that. There's less chance of you doing a gearbox in with your fingertips. The powershifters are a cracking idea but you've not got much feel for the box.

Yes, what you've said it basically spot on. Except to be honest 99% of the time the shifts the power shifter did seemed spot on. However as I am witness to you only need to properly fluff one of two and its bye bye gearbox. You are still possibly at risk with the fixed duration cut (read the geartronics FAQ thing on their website) but as you say if the cut is the wrong duration you're less likely to totally bugger it when you're using your fingers.

Unless you have fists of ham!

As Adie and others mentioned - an exploded diagram is the way forward, part no 25 is the mystery bit (you can see the "groove" between the two rows of teeth):



You can't see this collar from a quick glance at a set of gear clusters as it sits under the gears when the gearbox is assembled.

[Edited on 27/1/11 by hobbsy]

Part #25 looks more like a bearing to me?

Yeah I thought that at first but if you look at part 30 it looks the same on the inside and that definitely fits on to the splined part of the shaft.

Here is a full size version of the diagram which probably makes it clearer:

No25 is listed as a collar in my manual. 14, 27, 30 are bearings.

quote:

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Originally posted by adithorp
No25 is listed as a collar in my manual. 14, 27, 30 are bearings.

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Later today I'll pull one of my fairly knackered "spare" gearboxes apart (not one's I've killed personally but from other engines I've stripped for spares!)

Will post a photo. Let's face it - it's the gearbox I've killed and so chances are it's a gearbox part. If it's not from there then were is it from? (This was my initial concern!)

Finally (months later) the engine has been pulled out and the gearbox repaired.

Malc at Yorkshire Engines kindly did the repair for me and was quite surprised at what he found:



Apparently he's not seen one go like that before and I was very lucky that it didn't exit the crankcases!

There was luckily no other damage and the rest of the engine looked A1

At least this explains that those "chunks" were. I was at a loss at to how that part (no 25 in above diagram probably) could have escaped at it should be held in by the gear that sits around it - unless that gear "explodes"!

Oh and before any "hamfisted hobbsy" comments start re-appearing I'm blaming dodgy metallurgy for this freak failure!

[Edited on 3/4/11 by hobbsy]

Nice

So is the "collar" some sort of bearing or is it pressed in there?

I'm really glad you came back and concluded this.

Cheers
Davie

Blimey......... you were lucky there!!!