EC250 '98 gearbox questions

[Leon_gasgas]

Hi all!

After checking for damages in the gearbox of my bike ('98 year model) I would like to ensure that I put back in the correct order all the parts. The manual is clear enough for the order of the sprockets and the shift forks but not so clear for the mechanism which shifts the forks. Can somebody instruct me for its correct position in relevance with the forks?

Now I have put it in (I haven't assembled the cases yet) with the 2 left forks placed in the "lowest" (deeper?) "path" and in the "highest" path respectively on this mechanism. The one right fork is placed naturally in the middle path of this mechanism. Is this the correct order? By hand it shifts the gearbox into two obvious positions. The one in which everything turns around and the one in which (as I remember) 1 or 2 sprockets don't turn around. Into how many positions the gearbox should be shifted by turning the drum by hand?

Here is a picture of the forks in relevance to the primary axis and the drum. It is natural to me that it should be like that because the primary axis can receive one fork only. Can somebody verify?

http://img142.imagevenue.com/img.php?image=86949_GG_gearbox_split1_448lo.JPG

I hope my description is clear enough for you to understand! Waiting for your replies!

Thank you!

Leon

 

[Cruiser]

Leon,
It looks good in the pic, but its been a long time since I had my 97 apart. Hopefully GMP will post as he probable has pics of his trans apart.
Good luck,
Steve C

 

[GMP]

Sorry, last time I had one apart I had no digital camera handy.

It looks OK, but assemble it into the case and shift it through the gears. You can even temporarily assemble the case halves without the crank or gasket just to check this.

One thing to be carefull of is its possible to install first gear both ways on the countershaft, but only one is correct. It looks symetrical at a glance but there is a very slight offset. If its on backwards the trans will bind when the cases are mated.

 

[Leon_gasgas]

Thank you for the replies!

This thing about the first gear confused me a bit. How do I check it? I tried once to shift gears by hand with the gearbox assembled and the shift drum into its needle bearing but it stopped shifting (I don't remember to which direction I was shifting) after 1 or 2 shifts. It felt like the "deeper" left fork (left in the pic) got stuck and couldn't move. I will try it again now to see how it goes this time. Should the drum turn clockwise to shift gears upwards?

Thank you again for your help!

Leon

 

[Leon_gasgas]

Hi again!

Ok, I thing I understood what you wrote about the 1st gear. There was a picture in the manual too, showing which side of the gear should face the case. Tonight I will try to put everything together. The double rubber o-ring which is near by the outer front sprocket is damaged. It's like one side is ok and the other is less than half. Can I take this small part off and use a new single o-ring together with the old one, or is better to order the OEM one?

Best Regards,

Leon

 

[GMP]

Get two new OEM o-rings, new collar, and a new seal. Inspect the collar and you will most likely see a wear groove. Also, clean and inspect all the bearings. Personally, if I'm going through the trouble of splitting cases I change everything, all seals and bearings, and upgrade to higher grade parts where possible.

 

[Leon_gasgas]

Ok, I'll do that. It felt that the two outer bearings of the gearbox opposite from the chain sprocket were stucking so I replaced them with OEM SKFs. The other bearings are OK but maybe I will replace them because I have their replacement SKFs.

The funniest thing of all is that when I opened the cases to fix the hole on one, I found a broken big tooth but everything seems fine! All the gears are ok! Where this tooth came from? Any clues?

Best Regards,

Leon

 

[Leon_gasgas]

Thank you all for your help! The position of the shift forks was correct. Yesterday I started the bike and everything worked ok. I have put a new Vertex piston (the old one was still ok after 120 hrs asking only for new springs) as well, so tomorrow I will break it in well.

Thank you!

Leon

 

[Leon_gasgas]

Hi again,

During yesterday's break in it was quite impossible to shift from 2nd to 3rd. It was shifting to neutral and after a second trial it was shifting to 4th. It felt great shifting to all the rest of the gears. I always used the clutch. Because I was driving up and down a normal ground road I was wearing my normal hicking boots and not the enduro boots. Can this cause this problem? It was hard to downshift too between these two gears.

On Saturday when I drove around my home to check if things are ok, it was hard to shift from 1st to 2nd. Then I was using even softer shoes. Tomorrow I go for practice so I will wear all the enduro equipment. Should I check something else? With the bike turned off I can put it to 3rd easily by hand! I am really frustrated because except this problem the bike feels like new.

Should I change the position of the shifter? Something else?

Please help me! I wouldn't like to open the cases again.

Regards,

Leon

 

[GMP]

If everything worked correctly on the bench (shifted OK) you should have no major problems related to assembly. First thing is to check if your clutch is dragging. Was it bled properly? Let us know. Also, what if any parts were replaced in the transmission? There have been some updates since '98.

 

[Leon_gasgas]

You guided me to the correct direction! I just adjusted the clutch freeplay. It was too much. More than 1 cm! I followed the manual for 2-3mm. I am so angry to myself! I am so picky about many things and just did all the work myself with your help and I just don't check some basic small things! I hope tomorrow everything shifts smoothly! It should.

(I changed the 4 bearings (1 was broken and another was stucking), the 2 o-rings and the quite grooved spacer. Everything caused from me (the freeplay..) and a loose flatland skidplate which was causing the shift lever to stuck in every downshift (many false neutrals..) during a local race here in Finland.)

Thank you again so much!!

Leon

 

[Leon_gasgas]

Hi again!

I just came back from the forest. Problem remains. It will always go to neutral and then after I try again it shifts to 4th. The same when downshifting. I am so sad now. What could be the reason? I put everything in the correct order and nothing seemed broken or bent. If you can suggest something else please do it. Right now I don't have the power to even check the manual.

Regards,

Leon

 

[Leon_gasgas]

How big difference a not installed 18*31.5*0.7 washer can make? Can it be the cause of this problem? For assembly I followed the 2005 EC manual and in the picture there was no washer on any side of the 3-4 gears (this is double/stuck gears moving together by the shift fork). So, I was assembling step by step the gears, bearings and the other washers and in the end the above washer stayed in my hands. In the last steps it couldn't fit even to the shafts. So I thought it cannot cause any problems... but I think it does now. Because it goes to neutral upshift from 2nd or downshifting from 4th, in which side of the gears I should try to fit it if I open the cases?

Do you think this causes the problem? Any other things to check? Should I check something with the engine still on the bike? Like how the "shifters" turn around the drum?

Thank you!

Leon

 

[Leon_gasgas]

Hi again!

Problem found. The four side "teeth" (the ones going into the secondary III gear..) of the secondary VI gear are all broken. When I checked two weeks ago it seemed ok to me because I had no experience (even though I found at least two teeth in the cases!)... Now checking with a friend and knowing that the 3rd gear is the problem, it was very obvious. Tomorrow I will know if the dealer has this '98 gear. He has from newer models but there is a small difference and tomorrow he will be sure. If he doesn't have it, I have to wait to come from Spain. Hopefully it won't last forever..!

Thank you for your help!

Leon

 

[GMP]

Leon,

The major change is that in pre '01, the gears ran on plain bearings. In '01 this was changed to needle bearings. Some gears and the countershaft are different at the very least. If you can afford it and plan to keep the bike, it might pay to do the complete upgrade with all new parts.

 

[Leon_gasgas]

Hi!

According to the distributor this secondary VI gear is slightly different so he found for me a secondhand but in good condition complete gearbox for 300€. I will have it tomorrow.
Sometimes I feel that I want to sell the bike especially after this problem with parts availability. But then generally is in great condition and set up very carefully (Ohlins fork, Pro Taper 20mm clamps, a lot of revalving to my taste, etc.) All of my enduro friends with their new bikes (including Miska Aaltonen.. ok, he is amazed of the bike.. not from my speed ) are amazed of this "old" model. I think I keep it for sometime until something really great and much improved comes out from GasGas (anyway it does not lose its value so much anymore). I'll let you know when everything is assembled and working.

Leon

 

[Leon_gasgas]

Hi!

Gearbox fixed! Finally! The bike feels like new. Thank you for your help!

Leon