admacp Posted June 7, 2005 Report Share Posted June 7, 2005 I was swithering over the purchase of a gas gas 280 pro (04 model) for quite a while but a lot of people told me (and I have read a few tales of woe) that they are troublesome - in particular the gearboxes have a tendency to give problems. Guess what, I bought one only 3 weeks ago and...........the gearbox has gone bang on only my 6th or 7th time out on it! I have stripped it down and found that 2 of the gear cogs have sheared teeth. The cogs are combined (i.e double gears ) which are fairly expensive. I reckon I have tracked the problem down to a circlip which has "jumped" out of it's slot on the gear shaft and allowed the gear to move freely only about 2-3mm which in turn, loses about 30% of it's contact area with the other opposite gear cog and resulted in broken teeth on both of them. Is this the main problem that is affecting the Gas Gas gearboxes or do you think I have been very unlucky? I don't know whether to trust it now (what's to stop it from happening again?) and am wondering if the Gas Gas is the right bike for me. Quote Link to comment Share on other sites More sharing options...
jenkinsm Posted June 7, 2005 Report Share Posted June 7, 2005 Sad to hear about your problem m8. You are going to get a hell of alot of people replying to this post that "yes its a common problem".. bla bla bla. But its bull****!!! The 04 gearboxes were pretty sorted as they were altered from 04 onwards and from then they have given little trouble although admittably they have got a few other teething problems i.e. ignition etc.. I can understand that you will loose confidence in the bike but dont, you have being pretty unlucky i think, its probably come off as a result of a nock. Quote Link to comment Share on other sites More sharing options...
jjwhite Posted June 7, 2005 Report Share Posted June 7, 2005 he is too right, yes there was a lot of problems on the first pro's, but they had this problem just about sorted in 03, then to have an o4 go wrong is very unfortunate as i have not yet heard of 04 or 05 going wrong. my best bet would be to say that who ever you got it off didnt treat it well, kicked it into gear, didnt fully pull in the clutch when changing etc, this has caused the circlip to jump out of place and result in your problems, i will not say that there is no chance of it hapenning again as there is alwasy a slight chance, but i will say that if you take care of your bike, and ride it with affection, and not TOOOOO much aggression (we all need to be a little aggressive, but save that for sections not floging it on moor crossings!!!) then your ~should~ be fine. just hope that you dont lose faith in your bike, as if you like it to ride then you will only go down hill if you move to another machine. Quote Link to comment Share on other sites More sharing options...
windlestone Posted June 12, 2005 Report Share Posted June 12, 2005 In 02 the factory could not get a sufficient amount of shift shaft springs so they sourced some from another supplier who unfortunately didn't harden the springs. This was the main problem for early pro's having gearbox problems however people are quick to slagg the marque off and they say the gearbox's are suspect. 03 onwards the problems are rare and you will find that the developement gas gas has done on the pro and continue to do is highly commendable. Your 04 will be fine once you have repaired it Quote Link to comment Share on other sites More sharing options...
jools Posted June 12, 2005 Report Share Posted June 12, 2005 This is a bit off subject but just for your benefit. never stamp on the gear lever because the 'tophat spring' is very delicate and if that goes and you continue to ride the bike bits might find its way into the box - which is no good Use your toes. Just hate seeing people on gasgas's stamping on the lever down to first, coz it can end up being dear Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted June 12, 2005 Report Share Posted June 12, 2005 If the circlip is a "snap-ring" (with 2 holes for snap-ring pliers), make sure you put it on facing the right direction. They have a thrust side, and improper installation can make them pop off. Quote Link to comment Share on other sites More sharing options...
kinell Posted June 12, 2005 Report Share Posted June 12, 2005 If the circlip is a "snap-ring" (with 2 holes for snap-ring pliers), make sure you put it on facing the right direction. They have a thrust side, and improper installation can make them pop off. I seem to remember hearing this before, is one side totally flat with a right angle edge and the other side has a rounded off/bevelled edge? If so, which way should it go on? Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted June 13, 2005 Report Share Posted June 13, 2005 I'm not so sure that's always correct. The flat edge is the thrust side, and it should be facing the direction it would get shoved out of its groove. So whatever is doing the shoving, would contact the rounded edge. On a fork leg or a wristpin, for instance, the flat would face out. If the rounded edge is pushed against a squared slot, tha ring could get wedged open (if it is an external ring) or closed (if it is an internal ring). l l l ( l ( ( ( ( This is sort of a cross-section. If the thing on the right were being pushed toward the thing on the left, one of them would be levered out of the way. If they were both flat, this wouldn't be the case. Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted June 13, 2005 Report Share Posted June 13, 2005 Crap. My diagram was rearranged and it doesn't work now. The parentheses are supposed to be in a semi-circle with the 'hump' facing the vertical line. Quote Link to comment Share on other sites More sharing options...
jtt Posted June 13, 2005 Report Share Posted June 13, 2005 Just hate seeing people on gasgas's stamping on the lever down to first, coz it can end up being dear ...or on ANY bike for that matter...motorcycle transmissions (exclusing Harleys...sorry Charlie ) are not tractor gearboxes...no need to stomp on them, a gentle tap will suffice and be much kinder to the mechanism. Charlie is also correct that the flat face should be the thrust side. Pretty obvious if you think about it. Just think about the forces on the clip and install it accordingly. By the way the same "flat edge/round edge" thing is also present on clutch plates. Quote Link to comment Share on other sites More sharing options...
jools Posted June 13, 2005 Report Share Posted June 13, 2005 ...or on ANY bike for that matter...motorcycle transmissions (exclusing Harleys...sorry Charlie ) are not tractor gearboxes...no need to stomp on them, a gentle tap will suffice and be much kinder to the mechanism. Yeah, your right! its bad news doing that Quote Link to comment Share on other sites More sharing options...
admacp Posted June 13, 2005 Author Report Share Posted June 13, 2005 Ok guys - got the gearbox fixed and everything appears ok (so far!). The circlip to me was wrongly fitted in the factory. The rounded/bevelled edge was facing towards the direction in which the gear cog could "move", effectively slipping over it's seating in the groove. I would assume that the flat, sharp edge should be the side that is stopping the gear cog as it would be more difficult to be pushed out of it's seating. Unfortunately, some of the other circlips in there were also facing the wrong way!!! It was interesting to read that there is a flat side/sharp side to the clutch plates. If they were fitted the "wrong" way round (which is the right way round anyway?) would that have any effect on the clutch action? Quote Link to comment Share on other sites More sharing options...
jtt Posted June 14, 2005 Report Share Posted June 14, 2005 admacp, the plates should always be installed with the sharp edge facing outwards, towards the cover. In theory the sharp edge could catch on a burr or create a burr preventing the clutch from engaging properly. Personally have never seen it happen, but have always made a point of installing the plates this way just "because" Quote Link to comment Share on other sites More sharing options...
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