Gearbox help needed

Soo after a ride out last weekend i was going approx 80 and changed up from 4th to 5th using my quick shifter... Well I hit the neutral that seems to pop up there randomly, always scare the shit out of me, it then jumped into 5th gear... As I got down the road to a round about I was changing down and noticed a kind of clicking/ticking noise as if something near front sprocket was caught on chain... I pulled over checked it and seemed ok! I rode up the road to meet a member off here and I relised when slowing down it made this noise. Once stopped I checked the chain and noticed it was very loose.. Strange thing is that I had adjusted it approx 25miles b4 hand so knew it was ok.
We then headed off to meet some others and I relised that in 4th gear it was like there was tractor inside my engine!! Well not quite but was a loud noticeable crunching sound.. I did ride the bike rest of the day but tryed to avoid 4th gear.

Once home I tightened chain up and test ride bike and still make the same noise, i think it also makes the noise in other gears but no way near as loud, hard to hear over the noisey exhaust.

Anyway if you're still reading I called Aurther bike mad off here to get his advice and was going to see if he could do the work but he was very helpful and after a long chat convinced me to take gearbox out myself, so today I did, took approx 3hours BUT the gearbox looks ok to me, meaning no broken teeth/cogs... Now I really feel stuck, I suppose I better get the gearbox looked over by someone who knows what there looking at?
Was strangely hoping to find the box broken so knew what the problem was....

Here's a few pics

 

Also I was getting a whine in 6th gear since I've had the bike

 

looks like it wasn't too bad a job to take it out?

 

It's quite straight forward however I now wish I just got Arthur to do it as he knows what's he's doin lol and will know wot the problem is

 

Have you been looking around for a second box? probably not something that many people "repair" these days..

 

Not really... Wanted to see exactly what was wrong first, still none the wiser

 

Had another good look this morning, and I think I may of found a problem which may of caused the whining in 6th gear but please correct me if I'm wrong but as you see in the pic below the upper smaller bearing does not spin round smooth it feels notchy.. Also to the right hand side of the two bearings there is a mark on the engine casin as if something has rubbed there..?

 

my bearings whine a little as well from 4th upwards.. very slight noise but there never the less. I took a ZX-12 gearbox to bits last year looking for an issue with jumping out of gear and there were small marks like yours on the inside of the box / clutch basket as well.. yet nothing broken or floating debris.. some manufacturing / assembly marks? Did you have a good look around your oil when you drained it to see if any floaters?

 

I drained oil into a sive and nothin... All clear

 

your next step is to check the dogs on the gears,this is the gears that sit next to each other on the same shaft,not the gears that mesh together on the 2 shafts,basically where the 2 gears connect,they mesh by 5 dogs,the recess's on 1 gear,and the nodules (only word I can think of lol) on the other.look for wear on these around the edge at the top of them,they should be flat and square,if theres signs of wear they will be starting to slant on the tops.

 

Thanks for that, I just checked and you're right there is on 1 gear I can see that the dog/lug that interlocks is shered down on a couple of them... Hard to explain will add a picture

 

yep that the main issue with them,even more so on 08- boxes.basicall under load the gears slip out of sync,giving the false neutral issue

 

lugs,fuck me,thats the word i was looking for haha.

 

Like this...

 

hard to see properly,but look like theres some wear,actually looks like a chunk is out of it.

 

arthur is your man though,i'm just a tinkerer,but had quite a few blade box issues,and all teneded to be due to the dogs,not the actuall teeth.aqlso if you have a bent selecter fork,that can cause similar issues.

dont be afraid to strip the shafts of the gears,just make sure you keep track of how thay go back together,can be abit fiddly getting th eselectors back on,but as you've got so far,i'm sure you'll be fine.it's just a shame the 08- boxes aren't cassette like the -07's.

 

Ok cheers il give him a call tomo, he did say worst came to worst I could take the bike and bits over to him and he could put it back together lol. Il see what he suggests but that bearing I mentioned eairlier I have looked up in the manual and is an engine out job and casins split ect... Very exspensive!

 

Do you know which gear it is?? That's the damaged one

 

A better pic

 

hard to say tbh,but i doubt it will be jus the 1 damaged,have a good look at all the gears on both shafts