OzVMX Forum
Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: k2000x on January 23, 2011, 09:27:49 am
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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
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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"
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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
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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
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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..... :)
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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.
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I have a Montesa shop manual. 8)
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If it's an eighth the manual the Bultaco manuals are, I would be in shock.
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too true cappra
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;)
(http://i323.photobucket.com/albums/nn458/mx250syd/montesa/pg27.jpg)(http://i323.photobucket.com/albums/nn458/mx250syd/montesa/pg31.jpg)(http://i323.photobucket.com/albums/nn458/mx250syd/montesa/pg32.jpg)(http://i323.photobucket.com/albums/nn458/mx250syd/montesa/pg33.jpg)
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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.
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i found some here:
http://www.springmasters.com/sp/shims-support-washers.html
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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).
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if anyone wants shims or gaskets I have may have some or able to get them
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you haven't been able to buy a genuine Montesa gasket for about 25 yrs
Well, a reasonable copy with the correct thickness then.
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gaskets just to stop the oil leaking out the shims take up the slack
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Done right monty gearbox's are bullet proof believe me i have given over the years my mont box's some right stick and the only one to let me down was in 1975 on my 1975 mont when the box decided to stick in second gear, from memory when box was striped down the selector fork had come adrift but no other damage.