gasgas Posted April 6, 2005 Report Share Posted April 6, 2005 (edited) Last weekend i put in some new friction plates. The plates that came out had some lose friction material, so i decided to put in three new ones. Before reassemmbling i measured the old stack wich came to 9,75mm what is within specs. The new stack came at 9,65mm so i decided that was within specification too. I just test rode the bike and noticed clutch slipping when twisting the throttle in 5 and 6 gear. Clutch itself is a little notchy but i adress that to the new plates that need some aging. 2 things i am not sure off though. 1/what are the limits with the clutch measurements. Is 0,1mm making the clutch slip as there is not enough spring tention? 2/can the notchiness be adressed with a oil change. Maybe these new plates are better working with 5W30 oil, iso the atf dexron III? The new plates look different from the old one. So maybe they changed friction material from the 2002 plates to the new ones? I heard the old ones where kevlar, but what about the new one, as the documentation states 5W30 and now even 10W40 oil? By the way, is there a no synthetic oil that meets 5W30?? Edited April 6, 2005 by gasgas Quote Link to comment Share on other sites More sharing options...
blocky Posted April 6, 2005 Report Share Posted April 6, 2005 I've just changed the clutch plates on mine too. The new friction plates are thinner and there are one more of each type to make the stack up to the same thickness. If you've mixed old and new then thats why your having the problem. I had to change mine because the friction material on the outside plate had come away from its backing too. Quote Link to comment Share on other sites More sharing options...
gasgas Posted April 6, 2005 Author Report Share Posted April 6, 2005 there are one more of each type Blocky, what do you mean? I am a dutchman, and probably reading this wrong. Do you mean you took thicker drive plates to compensate for the thinner clutch plates. Like GG suggesting we shld do? What i am intressted in is, what are the outside specifications that still work with this diafragm spring. It must be very little. Can 0.1mm less tension on the spring mean slipping? Btw i didn't mix old and new plates, just put three new ones in. Quote Link to comment Share on other sites More sharing options...
blocky Posted April 6, 2005 Report Share Posted April 6, 2005 You can't buy single friction plates from gasgas uk anymore. You have to buy the complete assembly which consists of 7 friction plates and the metal plates to go between. The old assembly had 6 friction plates therefore I can't see how you could have replaced the broken plates with new ones without using new and ond ones together. Quote Link to comment Share on other sites More sharing options...
gasgas Posted April 6, 2005 Author Report Share Posted April 6, 2005 (edited) Oke, now i got it. Blocky, we are talking about a pro from 2002. They come with only 3 friction plates. Sorry i was so stupid not to mention this info. I immediatley add pro 250 to the topic header, to avoid further miss communication. Can somebody pls give some comment on the 5w30 oil. Is this mineral available? I like to try it iso the dexron III atf. Do the new friction plates have no longer a problem with swelling due to synthetic oils? Edited April 7, 2005 by gasgas Quote Link to comment Share on other sites More sharing options...
subira Posted April 7, 2005 Report Share Posted April 7, 2005 The official GasGas Jan 04 clutch bulletin suggest 9.75mm +0.1. i.e not +/- 0.1. Why didn't they write 9.80mm +/- 0.05 then If I read that correctly then 9.65 is too narrow, you need to be in the 9.75 - 9.85 range. There should be 2 steels and 3 friction plates. Put the steels on the outside when measuring. The same bulletin recommends the ATF Dexron III The bulletin can be found here: http://www.gasgasmuseum.com/PDFs/Clutch/Cl...letin-Jan04.pdf Quote Link to comment Share on other sites More sharing options...
gasgas Posted April 7, 2005 Author Report Share Posted April 7, 2005 Oke, Subira, So it is +0.1mm only. Then my problem is not enough tension on the disc spring. And that is why she is slipping when twisting the throttle in 5th gear. Maybe this also addresses the notchyness when slipping the clutch, although i am going to try a semi synthetic 5W30. This a little thicker viscosity and shld there for have smoother clutch action. Keep you informed. Due to the disc spring type clutch, this clutch works with rather narrow specifications. I understand now. Quote Link to comment Share on other sites More sharing options...
oceanvibe Posted April 7, 2005 Report Share Posted April 7, 2005 I just put in new spacer plates in my '02 250 pro. the thickness must be 9.75mm any less or more will cause slip/drag. I only took 0.2mm off the overall thickness to stop it dragging. Your old friction plates will more than likely have expanded a bit over time so putting in the new ones which will be a tinny bit thinner and still using the old spacers has given you the thinner clutch hence the slip. You can get the spacers in 1.3, 1.4 & 1.5 so you can adjust as required. I also change to using Dextron which I noticed a big difference with and at less than 2 quid a fill you can afford to change it every week ! Quote Link to comment Share on other sites More sharing options...
gasgas Posted April 10, 2005 Author Report Share Posted April 10, 2005 Today put some new plates in, and overall came to the important 9.75mm. Also discovered that one of the clutch lift fingers was sticking out and made the clutch action notchy. Put this finger upside down back in and this solved that problem. Now the clutch is smooth again. No more slipping when revving and no more notchiness when slipping Did a test ride this evening and i am happy with the result. Also tried a half mineral/synthetic 5w30 to create even more smoothness but didn't make to much, if any, difference. Thnks for everybodies help, till next time Quote Link to comment Share on other sites More sharing options...
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