Suspension dumby
 

I have to admit that as much as I am confident about most of the mechanicals of a motorcycle, I am completely lost when is comes to springs. I can change for seals and know how to set everything back to factory, but to tune it, I am lost. I am currently in the process of rebuilding my 99 gasgas ec250 and had planned on (based on a few suggestions and nice offer for purchase) switch my conventional zokes for newer gear, however due to cost overruns on other parts, I was not able to put the money into it at this time. Because of this, I have decided that, at the very least, I should get my suspension that I have working properly. I do know enough to know that that requires a lot of research and careful trial and error. I was hoping to find a few quick points from guys on hear familiar with my bike for correct setup. To this end, I have the following questions.

1. I am a 210lb (full gear) C trail rider from southeastern Ohio. I also race harescrambles and would like to keep the bike set up for racing (being that I am a C rider that probably means trail setup for you A guys). What would be the first big setup concern?

2. Does anyone have any other good tutorials (video preferably, I am visual) to help me learn about this stuff?

3. My rear OHLINS shock is stamped 596-12/58 L481 - Part number or does it mean something.

Thanks for any help. I am not expecting this to be spoon fed to me as I understand that a lot of my own research and time needs to be invested but a few starting pointers would really help me direct my search.

1. re-spring for your weight
2. get the fork disassembled and record the base valve shim stack, the rebound stack, the mid valve stack and float.
3. check pistons for bleed holes.
4. post info...along with your major complaints and type of stuff you ride.
5. bribe us with large amounts of alcohol.

imho, dont use the procedure for setting rear preload that i think the majority of the world uses.....that being where the preload is adjusted to provide x mm's of sag when you are sitting on it.

set the preload at a starting dimension, like 10mm, then adjust it at 2mm at a time till you get the feel you want. i'm sure if you search you will find this procedure detailed.

It seems to me that the book by Paul Thede of Race Tech fame might be that for what you are looking. It has a TON of photos, and explains the mechanics and processes. I am only to page 20 (and I've had the book for 2 months...i've been busy), but it seems pretty good.

The book is ~$24 from Amazon. http://www.amazon.com/Techs-Motorcyc.../dp/0760331405

it doesn't seem to be a sales pitch for Race Tech, but i am not too far into it.

I think that even if you decide to not do your own work, you'll better understand the first principles of suspension.

good luck.

Is that spring # correct, or is the "58" a "5" with a crossed "0" ? Its either a 58Nm or 50Nm, I suspect the later unless it was previously sprung for a real big boy. You should be 54Nm with 4.4Nm fork springs.

I don't remember where I got this write-up from, but the procedure does work. I believe the author assumes proper springs and rear sag adjustment.

Getting started, shock:
Setting the rebound:
1.) Find a relatively fast straight with braking bumps leading into the entrance of a corner. Reduce (Turn clicker out) the rebound damping until the rear end begins to hop or feel loose. Finally, increase (Turn clicker in) the rebound damping until the sensation goes away.
2.) Find a jump that tends to launch the motorcycle out. The rear end should absorb and then smoothly lift the motorcycle into the air. If the rear end bounces up, add rebound. (Turn clicker in)
3.) Find some large whoops. The motorcycle should track straight through the whoops with the rear wheel extending to the ground before the next impact. If it does not perform as described as above, it is packing and the rebound damping should be reduced! (Turn clicker out) (Please note the guide for sand set-up, as these rules don't apply for sand.)
Setting the compression:
1.) Find a corner with acceleration bumps on the exit. The rear of the motorcycle should follow the ground. If the rear end "breaks up", soften the compression. (Turn clicker out) (If this fails soften the rebound two clicks.) (Turn clicker out)
2.) Find some rough sections, a large jump and a couple of "G-Outs". The shock should bottom on the roughest section but it should not be a slamming sensation. Add compression to fight bottoming. (Turn clicker in.) But avoid going to far as small bump ride will be sacrificed in the trade. Remember the adjusters have a primary effect on the low speed, so even a large change in setting may only affect bottoming resistance slightly. Remember bottoming your suspension is not necessarily a bad thing. You should strive to bottom off the biggest bottoming load obstacle on the track. If you don't you're not getting maximum plushness from your suspension.
Getting started, forks:
Setting the compression:

1.) The forks should react to all track variations. If the forks seem harsh on small bumps or holes, soften the compression. (Turn clicker out) If they aren't, stiffen (Turn clicker in.) until they do feel harsh and then turn back a click or two.
2.) Now find the rough part of the track again. The forks should bottom over the worst obstacle. If harsh bottoming occurs, add oil in 5 mm increments.
Setting the rebound:
The rebound damping is responsible for the stability and the cornering characteristics of the motorcycle.
1) Find a short sweeper. When the forks compress for the turn, the speed at which the forks return is the energy that pushes your front wheel into the ground. If the forks rebound too quickly, the energy will be used up and the bike will drift wide, or wash. If the rebound is too slow, the bike will tuck under and turn too soon to the inside. Find the appropriate balance for each track.
2). With the bike turning well, the wheel should return to the ground quickly yet not deflect off berms or bounce off jumps.
Going to different tracks:
For hardpack to intermediate:
Set the compression softer, (Turn clicker out) front and rear to help get maximum wheel contact and plushness.
Sand tracks:
(Non-square edged bumps); More low speed compression and rebound are necessary. Start by adding 1-2 clicks (Turn clicker in.) of rebound and as the track gets rough, add compression 1-4 clicks. (Turn clicker in.) (Supplementary sand set-up techniques). Harshness is a result of packing in forks. Remember to add compression (Turn clicker in) to help keep the front end from packing. The rear suspension will exhibit packing by swapping. To eliminate swapping begin adding compression (Turn clicker in) until the bike tracks straight and then add rebound (Turn clicker in) to keep the rear following the terrain of each whoop. Don't be concerned if your clickers are nearly maxed out in sand conditions. Unless of course you had your bike revalved for sand.
Supercross:
(G-load, curb hits); G-loads produce slow piston speeds. This means that less dampening is produced by the shock and forks in a situation that causes more of a bottoming load. To set your bike up for Supercross adjust the compression stiffer (Turn clicker in) on the suspension (2-6), clicks and in some circumstances raise oil level and/or change to stiffer springs.
Unpleasantries?
Headshake:
Adjust the forks lower in the triple clamps.
Excessive rear end kick:
Check for packing, which is identified by kick to side in hard to loam conditions. If you observe packing, soften rebound. (Turn clicker out.) This cannot be avoided if you brake improperly and lock the rear wheel up and/or pull in the clutch, on the entrance to corners.
Keep a record of the different settings if you race different tracks. That way you can start at a point that worked well the previous times.

I am reading a 56 now - had my wife look at it with much better eyes than mine, and she sees a definite 56.


Thanks for the information. As usually GG guys come through with great info. I have ordered the race tech book and am going to look for the correct springs. I have about a month to get my bike back together then about another month to "fiddle" with it. Dave, I am going to print out and laminate your suggestions to try out when the bike gets back together. THANKS for all the help!