Gas Gas EC200 Rebuild

[Osnabrock]

Yesterday was my lucky day.
On top of scoring a subframe for next to nothing on Ebay, I scored a piston kit for the bike for half price in the flea market section of another moto forum.  I wish the piston kit had come up about a week earlier.  I'll just have to hold onto it until next winter when I figure I'll need to rebuild the top end.  
A question for those anyone who's had a shock rebuilt............Does it notably improve the performance of the suspension?  I'm often suspect of such things.  Today's performance suspensions have so much adjustability that it makes me wonder if it's more in the head.  I can see if the suspension is valved WAY off you'd want to do that sort of work but it looks like the changes that were done to this bike, as far as spring rate goes, is pretty much in line with my weight.  Any thoughts?

[Bogus Jim]

As I see things, there's a difference between rebuilding and tuning. Rebuilding is replacing worn seals and bushings, and fresh oil. Tuning is rebuilding if necessary, and then possibly changing oil weight, oil level, spring rate, bushing tolerance, and the valve stack. I would not expect a big performance difference from a rebuild, unless the shock was seriously out of spec. On the other hand, suspension tuning can dramatically change performance for better or worse. But take this with a grain of salt because I'm not a suspension expert. 

Neduro sells a $15 eBook on suspension tuning. (http://dualsportriding.com/)  This was very helpful to me for understanding suspension problems, and what can be fixed with the clickers, versus what needs to be fixed with a revalve, re-spring, or other tuning. 

[loingrader]

if it aint broke (or blown) don't fix it.

seriously.  ride it as is, see what the adjustments will do and after some time in the saddle you will know what kind of changes you desire out of your suspension, if any.  i would wait until the shock is blown (leaking oil) before i spent the money for a rebuild and a re-tune.

[greatbuffalo]

I agree. Run it at least for a while. If it works, wait. If it doesn't, take notes, what it well, what it does poorly. Then when it comes time to rebuild/tune talk to your rebuilder. If he or she knows what they are doing, they can tune the shock to your weight, type of riding you do and other needs. Sasquatch took all this into account when he did mine. Mine is tuned to carry my not so toned self and lots of gear on light gravel and 2 lane roads. It does those things well and other things ok. Unloaded and off road, not so good, but I do it anyways. It's really amazing how much difference changing the weight of the oil in your shocks as BogusJim eluded to, can really take the mushyness out of a shock.

[Osnabrock]

I'm just going to clean it up, bolt it back on, and go.  I may as well save something for next year besides the piston and rings I guess. 
As suggested, I think a bit more time on the bike would be a good idea before needlessly tossing money at a "problem" that doesn't exist.  The one weekend that I had it out, I didn't notice anything horribly wrong with the ride.  Even though I had the front end set seriously hard, it still rode just as good as my DRZ, and I think I've got that bike pretty dialed in.

[greatbuffalo]

Sounds like a good plan.

[Dr Psyko]

I had a 1980 ducati 900 ss (old bevel drive), and the shocks were bagged from sheer time, they didn't have many miles. I had the rear shocks rebuilt (seals and fluids, gas), and new fork springs and oil (1 step heavier), and the difference was dramatic. "Tuning" is a crapshoot until you know the bike, Rebuilding/replacing is almost necessary for any OEM shock over 10 years old. IMHO.

[Osnabrock]

With the decision to leave the rear shock as is, I continued on and pulled the swingarm from the bike.  I tend to do this with everybike that I purchase within the first year, new or used.  I know a lot of folks who have had real problems removing their swingarms due to the factory being quite conservative in their lubrication.  I want to avoid having such a problem.
The swingarm bolt came out but it wasn't the easiest thing I've ever done.  I had to loosen all the engine mounting bolts and be pretty aggressive with a hammer and drift to get the swingarm bolt out but it came out without damage.  It looked pretty dry but there was no corrosion to speak of.  Almost every other bike I've done this to has had a fair amount of white corrosion on the bolt.  A good sign.
With the swingarm off the bike, I can clean up the places that would be impossible to reach with it in place.  The area around the shock and swingarm is pretty dirty. 
The bearings all seem to be in good shape.  I'll likely just repack the bearings I can and reassemble it.

[Osnabrock]

I got a little further into the linkage and found that the rocker arm needle bearings were pretty solid.  I'm guessing that this part of the bike hasn't been through in it's 8 years of existence.  I'm guessing that the seals went bad. 
The bushing looks pretty bad on account of this.  I'll have to clean it up, get out the caliper, and see if there's hope for it's reuse or if I'll have to find a replacement.  New seals, and possibly new bushing and needle bearings, will have to go on the next order list.

[Hank]

Yeah those bearings look pretty tough.   

Watching this makes me want to start another project.

[Osnabrock]

Last night I was able to remove some of the bearings with a hammer and drift but others will too well frozen in place.  Here's a photo of a little trick that I came across that makes it possible to press out the stubborn bearings.  I'll do something similar when I need to install the new bearings.
I'll also put the new bearings in the freezer overnight before I install them to help the metal contract a bit first.  I did this once with my KLR steering head bearings.  I'm not sure if it helped or not but the install did go well.
I priced out OEM bearings to run about $20 a piece.  I'll need 5 for just the rocker arm and another 2 for the swingarm, $140 plus the cost of the seals, another $30 or so.  Ouch. 
Instead I found that both Moose and All Balls have replacement kits for the linkage and swingarm for less than $100.  I've used All Balls before in my KLR but haven't used Moose bearings.  Anyone have any experience with any other brands that they could suggest or recommend?

[Hank]

I have All Balls bearings in my TDM wheels.  I don't have a whole lot of miles on them, but so far so good.

You might want to just measure them and run down to your local bearing house and have them cross them.  A Whistler or Cartney Bearing house etc.

If you ever need to remove wheel bearings, Pit Posse has an awesome tool for it.  I think it was maybe 40 bucks and it makes wheel bearing removal literally a 5 minute job.

[Osnabrock]

I do have a bearing house just a few blocks from me.  I've gotten wheel bearings from them in the past.  I don't remember if I was able to get seals from them as well.  I don't even remember if there were seals on my wheel bearings.  I'll have to call and check tomorrow.  I'm sort of at a standstill until I get them and I'm eager to move along.

[Osnabrock]

I needed something to do this evening and since I have to wait to solve the bearing question I did a little work on my rear brakes. 
Right when I got the bike, I noticed that it was seriously lacking rear brakes.  As you can imagine, it's quite a surprise when you're riding along and realize that you don't have all the braking power you'd like.  Especially when your riding in the woods.  Sure your front brakes provide most of your stopping power but there's only so much front brake you can use without loosing your front end.
Anyway, tonight I decided I'd try taking the rear caliper apart.  I hadn't done this before and thought it might be a bit of a challenge.  I did a little research online and found that calipers are surprisingly simple.  It's just a piston in the caliper housing and a seal or two. 
Upon attempting to free the piston from the housing, I found that it was fighting me.  I applied a little penetrating oil and let it sit for a few hours.  I read that applying some compressed air would pop the piston right out.  It didn't work for me.  I reinstalled it on the bike and tried to use the normal action of the brakes push out the piston which didn't work either.  I ended up just prying it out as much as I could with a screwdriver and then pulling it out with a vice grip.  Not the best way but no harm was done either. 
I discovered a great deal of corrosion in the piston and the seal and o-ring were pretty gummed up.  I took everything out, sanded down the piston and cylinder with fine grit emery cloth, cleaned things up as best I could and put it back together.  The piston slid in remarkably well so hopefully that solves the braking situation.  I've also got a new brake line on it's way so I'll wait to install it and bleed the system until then.
I also need to find the tolerances for my rotors.  None of the literature that I've found on the bike give any specs for maximum wear so I'll probably just look in my DRZ or KLR's manual for their specs and assume they're similar.
Here are the before and afters of the cleaning process..........

[Osnabrock]

I've decided that I'm going to order a kit to rehab my linkage bearings, bushings, and seals.  I figure it's just easier to get a kit since I need all the parts.  The bearings and seals would likely be easy to get my hands on but the bushings would be a bit more difficult.
I'm unlikely to get much work done the next few days on account of my lack of needed parts and the fact that it's my girlfriend's birthday tomorrow so hold tight for a few days.