Suspension Woes

SATxMotoX

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Feb 6, 2001
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#1
I bought a old bike recently (87 KX 250) and I'm beginning to race it MX. When I first bought the bike (Feb 01) I didn't notice any problems with the suspension (more than likely due to I wasn't riding hard),but now 4 months later, the suspension is WAY soft (more than likely due to I'm riding harder/faster, hitting bigger jumps, etc.). I've noticed recently that I'm bottoming out the rear on the fender (have some nice black "skid" marks to show for it, too) and the front seems to be pretty undersprung too.

I'm 5'10", 235lbs (gear on), racing beginner MX (mostly natural terrain with loam). I have NO idea what springs are on right now as I haven't have much time (or patience, skill, etc.) to tear in to the bike. I'm pretty confident that they aren't stock (the rider before me was about 190lbs and he "claimed" he raced it MX) but who knows?

What ever I need to do I want to try to do as cheaply as possible right now. I know that most fixes in this case, going the cheap route, would only be temporary, but I'd like to try to do this cheap. If I can't, then I'll just have to buck up and fork out the cash.

My questions:

1. Can I get by for now with some "quick fixes"? (I.e. adding more oil, increasing air pressure in the nitro cannister, stiffining up compression, increasing/decreasing the rear shock preload, etc.)

2. What springs should I run in my bike? Should I get revalving work done on this bike? (Can this year model's shocks/forks even be worked on?)

3. Anyone want to take a shot at what I should set compression/dampning at? (BTW, the rear has both adjustments, the front only has compression)

4. I've noticed that on jumps if I'm next to a guy and we are doing the same speed he will always fly farther and higher than I will. Is that due to my weight vs. his, my shocks/forks being too soft and soaking up some of my forward momentum, etc.?

Sorry for the book. I'm really getting into the racing aspect of MX and would like to be as competitive as I can on my older bike but need to be as practical as possible and not start dropping some serious cash (which is why I got into the sport on an 87 KX 250).

Any and all suggestions are very welcome
 
Joined
Apr 19, 2000
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#2
Race Tech might be your best bet on the springs. You would need a .48 fork and 5.6 rear. I think RT has fork springs for that bike or contact your nearest Eibach dealer. Other companies can get them for you too most likely.

The cheapest fixes you can do as of now would be to get the forks and shock serviced which would include a oil change. You could run a heavier oil in the forks, like a 15 wt.

But, to make your suspension anywhere near what you need you should get the right springs, have the oil changed in both the forks and shock and use the 15wt oil in the forks. I would consider this minimum priority. The oil in your shock is most likely shot, ditto for the forks if it hasn't been changed in at least a year.

Maintaining your suspension is as important as maintaining your motor. You can't get good ride quality from worn out components, compromised spring rates or oil that is broken down.
 

SATxMotoX

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#3
Thanks for the tips Shock. I've got a Race Tech authorized dealer here in town and I spoke with him yesterday. He can turn my rear shock around in 1 day so I'm probably going to take it on over to get serviced. No telling what this guy will find when he tears that shock apart.

One question to you DRN suspension guys...what do replacement shocks run, on average? I mean the whole shock body, piston, etc. The Race Tech dealer told me that there is a possibility that my shock is extremely worn and will not be able to be rebuilt. Unfortunately, he wouldn't know that until he took the shock apart so that would leave me with the only option of buying a new shock at that point. Any suggestions? Buy another stocker or go for any aftermarket unit. In reading E. Gorr's book he suggests going for a reconditioned Ohlins unit. Any idea where to pick those up or even if I can get one for my year bike?

Thanks again for the help.