Author Topic: how to set up montesa gearbox  (Read 4777 times)

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Offline k2000x

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how to set up montesa gearbox
« on: January 23, 2011, 09:27:49 am »
putting together a vr250 motor what is the correct way to set gearbox up.. how much end float on shafts do i need and were can i get shims if required....could be missing some as motor was in 1000 bits

Offline cappra

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Re: how to set up montesa gearbox
« Reply #1 on: January 23, 2011, 09:38:51 am »
The book calls for end play of 0.004" to 0.008"  (0.1 to 0.2mm)
The shift drum should have an even number of shims on both sides.
quote: "barely perceptible end play in each shaft"

Offline gordon67

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Re: how to set up montesa gearbox
« Reply #2 on: January 23, 2011, 10:58:43 am »
Hi k2000x
cappra is dead right with the instructions....just make sure you get all the shafts centralised with the same end play because there is no room for error,...get it wrong and its a trip over the bars and damadged gears.....when you get the cases back together before you nip  them up  try selecting all the gears and make sure they are all ok before you assemble the rest of the motor....you will need a complete set of shims......if in doubt get some one to do it for you thats done it before .....good luck

Offline k2000x

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Re: how to set up montesa gearbox
« Reply #3 on: January 23, 2011, 03:06:24 pm »
is there a work shop manual i can buy...cappra does the shift drum need end float...i have an enduro motor spare wich i might crack open and rob a few parts

Captain Bilko

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Re: how to set up montesa gearbox
« Reply #4 on: January 23, 2011, 05:01:37 pm »
I've done it a few times as it's set out in the Clymer manual. It pays to do it that way as some centre gaskets vary in size. It all seems a little confusing but once you've got your head around it, it's very rewarding to have worked it all out yourself.
As Gordon stated, just make sure everything turns nicely when you have the cases back together, nothing binds and there's no noticable end play..... :)

Offline cappra

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Re: how to set up montesa gearbox
« Reply #5 on: January 23, 2011, 05:07:50 pm »
No workshop manuals exist.  The Clymer manual does have a
pretty good section on transmission setup. Shift drum needs the same
end float.  I have done enough trannys to know what I need in the way of
shaft play, so I do it by feel.  The "down and dirty" way to do is to leave the
crank out of the cases, install the three shafts with a centre gasket, fit the left
side case half and use 4-5 case bolts around the shafts, tighten down and
check the shaft play.  

Captain Bilko

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Re: how to set up montesa gearbox
« Reply #6 on: January 23, 2011, 05:18:48 pm »
I have a Montesa shop manual.  8)

Offline cappra

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Re: how to set up montesa gearbox
« Reply #7 on: January 23, 2011, 05:31:21 pm »
If it's an eighth the manual the Bultaco manuals are, I would be in shock.

Offline hitatreeonce

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Re: how to set up montesa gearbox
« Reply #8 on: January 23, 2011, 06:15:54 pm »
too true cappra

mx250

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Re: how to set up montesa gearbox
« Reply #9 on: January 23, 2011, 08:41:52 pm »
 ;)


TooFastTim

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Re: how to set up montesa gearbox
« Reply #10 on: January 23, 2011, 09:19:16 pm »
Make sure you have a genuine Montesa case gasket. Too thick or too thin and the gearbox won't work. I found out the hard way.

dutchtwinshock

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Re: how to set up montesa gearbox
« Reply #11 on: January 24, 2011, 12:31:05 am »

Captain Bilko

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Re: how to set up montesa gearbox
« Reply #12 on: January 24, 2011, 08:30:07 am »
Make sure you have a genuine Montesa case gasket. Too thick or too thin and the gearbox won't work. I found out the hard way.

That's why you should take the time to shim them up (as per the Clymel manual). Then it doesn't matter so much about the thickness of the gasket (you haven't been able to buy a genuine Montesa gasket for about 25 yrs).
« Last Edit: January 24, 2011, 08:31:48 am by 66M »

Offline hitatreeonce

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Re: how to set up montesa gearbox
« Reply #13 on: January 24, 2011, 08:43:57 pm »
if anyone wants shims or gaskets I have may have some or able to get them

TooFastTim

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Re: how to set up montesa gearbox
« Reply #14 on: January 24, 2011, 08:56:32 pm »
you haven't been able to buy a genuine Montesa gasket for about 25 yrs

Well, a reasonable copy with the correct thickness then.