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Hi guys

Is anybody able to tell me if the gearbox components form 2001 F4 can be used in 2008 F4 - like gears, selector forks , drum etc ?
 

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?

There are different internal ratios through the years....

So you might not be able to switch individual gears, pairs yes

I wouldn't bother just buy a complete used gear box they're cheap


:popcorn:
 

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There are different internal ratios through the years....

So you might not be able to switch individual gears, pairs yes

I wouldn't bother just buy a complete used gear box they're cheap


:popcorn:
Want to sell me that one you have cheap? :naughty:

It would compliment my track bike beautifully. :D
 

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wakey wakey eggs and bakey. Sorry I fell asleep with the last one. Forgot that is where that SPR box resides ... call you in a minute...
 

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Hi guys

Is anybody able to tell me if the gearbox components form 2001 F4 can be used in 2008 F4 - like gears, selector forks , drum etc ?
Noel and Ed's advice is good advice, there are differences in shaft sizes as well as spacer too, so compare part numbers first.
This picture form a fellow forum member show's the differences between a 100R and 312R gearbox, so I'm not sure how a 750 even SPR box will compare.
 

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I've got a couple extra in my garage I'm trying to figure out as well. I think one is from an 06', and the other from an 08' 312R... but still working on that.
 

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Discussion Starter #11
Thanks Guys

I have a 2008 312R - i'll drop the box and see what needs replacing..

The problem sems to be the gear lever return spring has become very stiff/strong so when on track and accelerating hard i keep missing geras and hitting false nuetrals - with a quickshifter and short shifting.

The gear lever moves freely - but the spring pressure needed has become quite extreme - rather than a smooth click when changing gear - its a heavy effort to lift the lever .. very weird ..
 

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The problem sems to be the gear lever return spring has become very stiff/strong so when on track and accelerating hard i keep missing geras and hitting false nuetrals
I have a similar issue on my 2002 F4 track bike but my false neutrals come on downshifts when trying to rev match. I'm running a GP shift so that could explain why my box behavior is opposite of yours.
 

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The gearbox return spring is just that, a return spring. It can not become "stiffer", if you're struggling to change gears up or down, it's probably because something is worn, either the shift fork or the gear selector barrel.
It's best to strip the gearbox and repair it rather than buy another dodgy box.
 

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I bought a 2001 clutch basket of fleebay for my EVO3 a few years back and it didnt fit, spline and positioning was fine but the OD was slightly larger and hit another component. Shows they made some changes in the early years.
 

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The gearbox return spring is just that, a return spring. It can not become "stiffer", if you're struggling to change gears up or down, it's probably because something is worn, either the shift fork or the gear selector barrel.
It's best to strip the gearbox and repair it rather than buy another dodgy box.
A weak shift spring was the reason my KTM wasnt shifting smoothly, especially when trying to change twice. It's the cheapest thing to fix if you're not sure what's wrong.

Gear boxes are a whole mess of complicated-ness that I avoid, if possible.
 

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A weak shift spring was the reason my KTM wasnt shifting smoothly, especially when trying to change twice.
That's a completely different scenario though Tim, if the spring is weak and doesn't return or rotate the selected drum quick enough then you'll not be able to select the next gear quickly.
This is different to what Spud is saying is happening to his gearbox, if I'm not misunderstanding something here.

The MV gearbox is very easy to work on, guys must just be carefull because the parts list and the workshop manual doesn't show the same sequence of parts, so make notes and take pictures as you strip the gearbox if you're doing it yourself.
 
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