'89 kdx suspension

[nemoskid]

I just picked up this bike and am again riding after many years off. As an intermediate rider on backyard tracks weighing 225 lbs. this is plenty of torque and horsepower so far but not nearly enough suspension. Just this weekend I cranked down on the rear shock preload 5 turns which helped a bunch on the ass end but landing flat is killer on the wrists, elbows,etc. I am thinking of installing Race-Tech .46 fork springs and am curious if anyone has a better solution. I am a mechanical novice so any info will be helpful. "If you are not crashing every now and again you are not getting any better"

 

[SQUIRLEYMOFO]

I just asked a similar question about a 90 kdx 200 and I weigh about the same maybe we will get some responses.

 

[dirt bike dave]

Stiffer springs will help a bunch, but 0.46 might be a little too stiff for trail work, IMO. Race tech cartridge fork emulators make a big improvement to the front suspension on that bike (I had a '90 and my buddy had an '89). I think we used 0.40 kg/mm springs front, stock rear spring, weight around 185 or so.

 

[Dazza]

for the front put in stock xr400 springs.
You will love it.

 

[nemoskid]

Dazza, xr400 as in Honda?

 

[nemoskid]

Dirt bike dave, never even heard of a fork emulator, would it help for primarily motocross riding?

 

[dirt bike dave]

The emulator is a Race Tech invention that really works wonders for forks that pre-date the more modern cartridge systems. On your old stock forks, damping is controlled by oil being forced through small holes in a tube. With the emulator, you dis-assemble your fork, and make the holes in the tube MUCH larger, so the oil is barely restricted. The 'emulator' sits on top of the tube the oil flows through. It is a machined peice of aluminum with large orifices in it, and a spring loaded plate on top. The damping is controlled by the oil moving the spring loaded plate. The spring is adjustable, but you have to pull the fork springs out to adjust. With the emulator, your stock compression adjuster on the bottom of your fork is disabled.

Combined with stiffer springs, the end result is a fork that is more plush on sharp hits such as rocks and roots, but able to handle big hits much better than stock.

Increasing your fork oil level will also improve bottoming resistance. The stock fork springs are WAY too soft for a big guy on an MX track!

 

[JasonWho]

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[nemoskid]

Thanks for the help guys. My plan is to install the .46 springs from Race Tech, they may be a bit firm at first but I dont plan on riding any less agressively as my skills improve. I am thinking I willl take on the emulators as a plan "B" if the dampening needs further refinement. It seems a bit more challenging as a mechanical undertaking and honestly I will need some track time to feel out the dampening issue. I had one salesman tell me I must upgrade my rear spring also, as my 5 turn adjustment on the preload effectively diminished swingarm travel. Sounded like B.S., any thoughts?

 

[Canon]

Somebody point me towards the Eibach .43 springs that JasonWho speaks of. I am in the same boat and pilot an 89KDX. Thanks.

 

[JasonWho]

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