K3 Engine fix - The Gearbox

[muzikill]

Ok, so the engines split im now posting some pics up to let those in the know have a look and see how it looks so far ....



Selector drum looks fine to me, although slightly discoloured hmmm. but the whole problem was 2 to 3rd gear movement/mechanism not working.

Here are the bits i found!


Yup, the first pic is a selector fork 'end', the pic aint the best bit it's sheared and then it was 'munched' in the gears somwhere. The 2nd pic is of some teeth 'bits'

My thoughts after reading the manual and based on the problem was gearshift fork '3' for the 3rd/4th gear. I'm expecting to remove it and find the '3rd' gear side of the selector fork to be sheared and the corresponding teeth on the gear it hit to be missing when it happened. I also notice the selector fork 'pin' the goes into the selector drum looked a bit worn.

btw, the oil strainer was amazingly clean! - there was nothing trapped in it.

Questions i have.

*I need to read up on how a sequential gearbox looks/works in practice/theory - any help/links?
*How does it select neutral/1st/2nd if the selector forks only do 3rd/4th/5th/6th ?
*The selector drum discolouring - normal?
*Buy a whole gear box from ebay or what i need only oem
*How do it test it works before putting it all back together?
*Why have i posted so many threads for something others have done in only one?

I can only pass on what I was told years ago by a very proficient tuner in UK where i then lived. Any parts showing wear should be renewed. It is pointless thinking one part is acceptabley worn. To then find out it wasnt, as you take a test ride many assembly hours later. Yes the drums do show some discolouring.
If its just a few parts I would not look at ebay as they might go same way after a few days riding. Could be longer could be less.
Sorry i cant answer all questions.

[yorkie_chris]

There is something in K3 box that is not the same as rest of pointies, so beware. I believe it is the input shaft is actually the same as the curvy instead of pointy, and needs to match the cases. Or it could be one completely on it's own.

I would not reuse your shafts as the gear bits getting munched in them can bend them.

[muzikill]

well before i broke it all down and discovered the fault i was able to change it down gear and before i stripped it the bike was able to run & change from neutral to 1st to 2nd gear and back down again. i dont think the shafts are any problem - plus i turned it by hand on the stripdown and didnt feel any 'tough' spots or wobbles. The bearings are fine as well, if there had been any damage to the shafts then there certainly would be damaged bearings.

Before i did this i was toying with buying a whole gearbox from ebay anyways just in case.

K3 got different gearbox parts? - typical! - can anyone else confirm this as well?

most of the gearboxes i see for sale usually say they will fit all makes of sv....

It is classic way how gear fails on sv, dog breaks of the gear. Replace broken gears. Also check surface of gears where pieces may got munched.
Drum discoloring is normal, it is from hardening process.
Take 3 forks out and snap picture. Wear showing on pin of fork that goes in selector drum is also normal as long it is just shiny.

Originally Posted by yorkie_chris

There is something in K3 box that is not the same as rest of pointies, so beware.

It is same as curvy.

[muzikill]

What about that 'notch' to the top right on the selector drum pics? - the pics i have looked at elswhere arent close enough to check it is right - it doesnt look as if there is something amiss with it, it kinda looks like its a 'lining up' marking.

Just the way it is casted, all are like that. Groves are only thing that matters. If you look in groves you can see line fork pin leaves. make sure they are not to deep.

[muzikill]

I dont know why they didnt just cast the top of the drum 'fully' if you know what i mean, all of those spaces look like they create 'weak spots' to me!

[yorkie_chris]

There's not that much force on the drum compared to the dogs.