October 10, 200619 yr Anybody know why some people change the master cylinder and hose on the Pro. I've seen quite a few with the bigger master cylinder on with a larger diameter hose and i'm wondering if this would change the clutch action ? cheers
October 11, 200619 yr No change at all to the clutch action, you still pull it towards the handlebar to engage. Do you use the clutch?
October 11, 200619 yr No change at all to the clutch action, you still pull it towards the handlebar to engage. Do you use the clutch? do you use the clutch most clutch levers pull towards the handlebar to disengauge the clutch
October 11, 200619 yr No change at all to the clutch action, you still pull it towards the handlebar to engage. Do you use the clutch? Can't imagine you get many cleans with that clutch!!! The larger master cylinder does make a difference. It makes the clutch have a slightly smoother action and makes it slightly lighter to use. I am not sure how this works because the actual cylinder assembley is the same so I think it is the pivot points on the levers that are slightly different to give that effect.
October 11, 200619 yr The larger master cylinder does make a difference. It makes the clutch have a slightly smoother action and makes it slightly lighter to use. I am not sure how this works because the actual cylinder assembley is the same so I think it is the pivot points on the levers that are slightly different to give that effect. Surely the larger reservoir and hose means more power at the slave for less pressure at the lever? Actually, shouldn't that be larger reservoir and smaller hose... so there's more fluid to push but it's sent at a higher pressure. I'm not quite as clear as I'd like to be on the effects of different changes to hydraulic systems.
October 11, 200619 yr The size of the reservoir and the hose make no difference, it is the diameter of the master cylinder that make a difference. A bigger diameter master cylinder will require more lever force (for the same lever pivot point), as an example if the master & slave cylinders were the same diameter you would only have to pull the clutch lever a millimetre or two to disengage the clutch but you'd need hands like Geoff Capes to do it.
October 12, 200619 yr it is the diameter of the master cylinder that make a difference. So, what we look for, to lighten the pull, is a smaller diameter master cylinder, but with more stroke, to get the neccesary displacement at the slave cylinder!? Which master cylinder will that be(part nbr)? Some people telling about a Montesa master cylinder?
October 12, 200619 yr Yes, the ratio of master cylinder cross sectional area to slave cylinder cross sectional area gives you the actual mechanical advantage Edited October 12, 200619 yr by Grib
October 12, 200619 yr After studying this post and my phsics books, to lighten the clutch there needs to be a smaller master cylinder but then this means you need more stroke to move the slave the same distance as before, so I guess its all about getting a balance. Edit:This is my 100th post I am now an advanced member! YAY!!! Edited October 12, 200619 yr by seandellear
October 13, 200619 yr After studying this post and my phsics books, to lighten the clutch there needs to be a smaller master cylinder but then this means you need more stroke to move the slave the same distance as before, so I guess its all about getting a balance.Edit:This is my 100th post I am now an advanced member! YAY!!! so whats the answer
October 13, 200619 yr A smaller master cylinder will make the clutch lighter but you will need to pull the lever further for the cluch to disengage. And to complicate matters I think the 02 side casing had a diferent size slave cylinder!! The answer is to leave as standard and make sure the cluch pack is the correct thickness as when it gets worn the bevel spring sits at a steeper angle making the clutch harder to operate. GasGas UK sell steel plates of diferent thicknesses to sort it out.
October 13, 200619 yr I agree, my 03 250 pro has a standard master cylinder, correct clutch pack thickness and ATF in the gearbox, the clutch action is fine.
October 17, 200619 yr Now you're got me thinking . . Given the clutch, clutch springs and the slave cylinder remain the same . . . no matter how you figure it, it will always take the equal amount of force [ pressure x fluid volume] to move the clutch plates a given distance.. so what will make the clutch lever easier to pull is only greater leverage, but this equals longer movement . . . If you increase the master cylinder bore, then youre pushing a larger volume of fluid but its harder to pull . . . everything just works of the other so it seems to me there is no magic way to achieve easy lever movement with a shorter lever stroke . .
October 18, 200619 yr Shorter lever stroke will always equal more force to pull the lever no matter how it is achieved. I would have thought that a longer lever stroke would give a more progressive clutch, but then I suppose you may run in to problems with the clutch not disengaging fully.
October 18, 200619 yr Adjust your clutch plates to 9.8mm fit a 06 125 raga clutch casing and bingo light clutch
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.