13 replies to this topic

[coxy_gg]

hi

im looking for some help or advice please, ive got a 2006 gasgas 250 pro and the clutch on it seems to be very heavy to the point where its hard to pull in and is hurting my fingers whilst riding. im just wondering if anyone has any idea of making the clutch lighter without spending too much money

i have already checked the pack height and finger height and all is good in that region and all seals etc are fine, im also wondering if the smaller clutch hose that came standard on the 06 bikes would make any difference and would it be lighter if i put a bigger diameter clutch hose on??

cheers

coxy!

[shercoman2k8]

Even with the smallest hose it shouldnt be too heavy! I think you may be using a very heavy weight of gearbox oil... try getting some 50wt gearbox fluid with cluth additives then get back to us

[JSE]

coxy_gg, on Mar 1 2009, 05:35 PM, said:

hi
im looking for some help or advice please, ive got a 2006 gasgas 250 pro and the clutch on it seems to be very heavy to the point where its hard to pull in and is hurting my fingers whilst riding. im just wondering if anyone has any idea of making the clutch lighter without spending too much money
i have already checked the pack height and finger height and all is good in that region and all seals etc are fine, im also wondering if the smaller clutch hose that came standard on the 06 bikes would make any difference and would it be lighter if i put a bigger diameter clutch hose on??
cheers
coxy!

Coxy,
I can probably give you a couple of suggestions that might help and my experience of the 06' clutch is that your condition is unusual. I doubt that a larger hose would help that much (probably only under higher volume movement of fluid, the smaller hoses are mostly are used to reduce flex) but completely flushing the fluid out of the system and replacing it with DOT-5 (Silicone) adds smoothness. It also may be that the seal/o-ring in the top-hat has expanded and creates a lot of friction and perhaps replacing that will help. I'm trying to remember and hopefully someone out there will correct me if I'm wrong, but I think the 06' was the first year that the thinner Belville spring was used and your clutch pull should be less than an 05', for instance, so I'm thinking there's something wrong somewhere. You might want to check the top-hat movement by pushing on it carefully, there should be some minor resistance but the movement should be smooth. An obstruction in the hose or fittings might also cause a problem, but this is also unusual.

If you really want to make the clutch butter-smooth (and your seals last a LONG time), you can lightly polish the top-hat and master cylinder bores with very fine rubberized abrasive (the brand I use is "Cratex") mounted in a Dremel tool. I know this is probably more than most riders want to do, but it does help a lot. I just happen to be familiar with it as I've used it for many years in building race engines.

Jon

[AMCQ46]

I had a similar issue on my 06, and I changed the o-rings, fitted the large diameter hose and replaced the plates and set the finger height to spec......................it made almost not change!

What I then did was to get one of these skimmed clutch springs .clutch spring and it has been great since then.

even with postage from USA it was still a cheep mod, clutch is now superlight and I dont get any clutch slip, so it could be worth a try for you.

[hoggle]

AMCQ46, on Mar 2 2009, 03:09 PM, said:

I had a similar issue on my 06, and I changed the o-rings, fitted the large diameter hose and replaced the plates and set the finger height to spec......................it made almost not change!

What I then did was to get one of these skimmed clutch springs .clutch spring and it has been great since then.

even with postage from USA it was still a cheep mod, clutch is now superlight and I dont get any clutch slip, so it could be worth a try for you.

I have a 2005 250 and would also like to make the clutch pull lighter, you don't notice it at first when on the Bike for a short time though after a few hours you certainly do ! So do you think by investing on this " Clutch spring" for my 2005 it would make it easier for me ? Many thanks, Hoggle !

[AMCQ46]

Hoogle,
on the 2005, I think you have 2 options:

1) as JSE said, the 06 had a thinner Belville spring [clutch spring on a GG] than the 05, so your dealer should be able to sort you out with the newer part which I think is 10% less stiff.
2) Get the LiPSE spring from Jack in the USA, and although he would custom machine it to suit your bike, skill, weight, it would be at least 10% lower than the 2006.

I am very happy with the change the LiPSE made to my bike, and at least 1 of my mates also bought one after trying my bike, and has the same good report.

[coxy_gg]

thanks for the replies guys. i am currently using putoline gearbox oil so not sure what thats like but maybe an idea to change and try a different type?? if so what type do you reccomend? i dont really fancy shipping one of them springs across from the usa and not even sure that it will work although a couple of people have given good feedback. will ring local dealer tomorrow and see what he suggests to lighten it up because at the minute its far too heavy and even after riding the bike through one section i have pains in my fingers and arms, that how hard it is to pull!! maybe the o-rings have expanded but not too sure where they are and how to chec so would be nice for any information or diagrams on this for me to be able to strip down and have a look would be nice.

by the way its not the clutch smoothness im worried about that all seems to be fine its just the weight of the clutch as i pull it in it seems very very hard to pull in compared to that of say an 07-09 bike so does anybody know the difference between the 06 clutches and say the 09 clutch or is there none?

thanks

coxy!

Edited by coxy_gg, 02 March 2009 - 11:19 PM.

[shercoman2k8]

If I recall the 06 gasser uses synthetic oil only, the effects of using mineral can be quite surprising... Just so happens that most putoline gearbox oils are mineral and there synthetic a rather silly price!

Also, your plates could of swollen? The tolerance is around 9.74-9.77mm if i remember correctly!

This means taking the clutch basket out and measuring the thickness of all the plates together if they measure more than 9.75mm this is probable the problem, You will need you buy an alternate plate to reduce it down to 9.75mm. If you phone gas gas uk they could sort you out with a steel plate to bring the thickness back down to the proper figures! If you dont fancy buying stuff take the thickest plate to your local machinist and get him to skim it slightly to reduce the thickness although this is likely to increase clutch slippage!

Do you know any history of the bike? has there been a water contamination in the oil? water pump seal gone in the past? Also sometimes a change in oil can cause plates to swell!

Edited by shercoman2k8, 03 March 2009 - 12:51 AM.

[laser1]

GasGas USA specs NON-Synthetic 10-40wt oils for the clutch/tranny. However, Just about everyone I ride with either uses ATF-F (fast / hard engaugement) or GM transfer case fluid - autotrac (blue stuff) for a slower, less aggresive enguagment. The ATF became very popular to avoid plate swelling back when that was an issue. Its also cheap, so you can replace it often w/o breaking the bank. My dads shop jackscycles makes the lighter spring, but I know he would tell you to make sure the clutch is working normally before installing the LiPSE spring so I would stick with OEM until your happy its working right. The lighter 06 spring with JSE's suggestions should feel very nice. The 06 spring alone is about a 20% easier pull (very noticable) as compared to the older versions.

You mentioned that you measured the pak thickness and finger height. What were the readings?

[coxy_gg]

the putoline gearbox oil that i use is fully synthetic stuff so that shud be orite shudnt it?? or shall i try using semi-synthetic or will this just make the problem even worse??

yeah ive had the bike since new and its basically a reconditioned engine ive just had a fully new gearbox and all bearings and then clutch bearings put in it aswell and before it was taken apart the clutch was fine nice and easy to pull etc but am wondering if because its been stood for so long has the plates swollen or the o-ring swollen or something to make it go like this.

yeah i could try taking the plates out and checking them because i just measured the pack height as a total so will do that when i get back into the garage, skimming the clutch plates is no problem i could do that myself at work quite easily on the machines we have if needs be and i have plenty of other plates which i could check with to get it to the right size if they are swollen too.

urm the clutch height of the pack was about 0.07mm above what it should be and thats within tolerance i think from what i remember from the book. finger height was again 0.07mm below what it should have been so i think that is all fine.

coxy!

[JanDyb]

coxy_gg, on Mar 3 2009, 06:14 PM, said:

urm the clutch height of the pack was about 0.07mm above what it should be and thats within tolerance i think from what i remember from the book. finger height was again 0.07mm below what it should have been so i think that is all fine.

coxy!

Hi

If I remember correct 0.1 mm higher clutch pack makes 2 mm (!) difference to the finger height...

-Jan

[coxy_gg]

if thats right then maybe i should alter the pack height so its less. if the finger height is say lower would this make the clutch heavier than the clutch fingers been higher??

[JSE]

coxy_gg, on Mar 3 2009, 03:30 PM, said:

if thats right then maybe i should alter the pack height so its less. if the finger height is say lower would this make the clutch heavier than the clutch fingers been higher??

Due to the mechanical leverage/pressure plate travel, a lower finger height (thicker clutch pack width) will tend to result in a harder to pull lever (and a "faster" engagement). I'd shoot for about 17.5/18mm height. There is a limit to how high you can go on the fingers as the servo cylinder will not be able to retract back far enough, although I imagine you could space the cover out a little with an extra gasket, but I've never tried that as it might create an unforseen problem.

Jon

[coxy_gg]

hi everyone

thankyou very much for all your replies, just thought id let you all know what the problem was or atleast what it seems to have been. when i took the clutch pack out and measured it it measured 10.2mm so been and bought a brand new clutch kit and put that in today and the clutch height was 9.82mm and it seems to have sorted the problem now

thanks

coxy