Shock Rebuild
- Thread starter kdx Clark
- Start date
Oregon Trail
~SPONSOR~
- Aug 2, 1999
- 263
- 0
If you're just changing the oil and gas, it's easy to do yourself. :thumb:
canyncarvr
~SPONSOR~
- Oct 14, 1999
- 4,005
- 0
If someone else is doing it, I would consider time, availability and shipping charges to be an issue.
Don't know where you are in illinois, but mx-tech is maybe close? They've done mine before. Worked fine.
Everything is easy if you know how to do it. Rebuilding a shock isn't 'hard' (I say conclusively having watched it done once ;) ). That's not to say knowledge isn't required.
Is that mark on the shaft a problem?
How do you keep air out of the assy on put-together?
Is your bladder shot, or just deformed some?
How do you fix THAT (the deformed part)?
What fluid do you use?
Going to change the shim stack?
To what?
And, yes...who's going to put the gas back into the bladder?
Not insurmountable questions, but questions nonetheless.
My last shock service I chose to drive an hour up the road, spend 1/2 hour watching it being done and chatting with a knowledgeable tuner, put it back in same day.
Don't know where you are in illinois, but mx-tech is maybe close? They've done mine before. Worked fine.
Everything is easy if you know how to do it. Rebuilding a shock isn't 'hard' (I say conclusively having watched it done once ;) ). That's not to say knowledge isn't required.
Is that mark on the shaft a problem?
How do you keep air out of the assy on put-together?
Is your bladder shot, or just deformed some?
How do you fix THAT (the deformed part)?
What fluid do you use?
Going to change the shim stack?
To what?
And, yes...who's going to put the gas back into the bladder?
Not insurmountable questions, but questions nonetheless.
My last shock service I chose to drive an hour up the road, spend 1/2 hour watching it being done and chatting with a knowledgeable tuner, put it back in same day.
- Jan 8, 2000
- 3,331
- 1
Do you have an independant 3rd party shop nearby? I have had GREAT luck with our local shop. Afterall, a shock is simple and you can specify what components you want.
- Thread starter
- #6
I haven't talked to the local guys yet- mostly 'cause the parts department doen't impress me much. Seems like they are more interested in selling me a new bike than in the $20 part I want. :| Anyway, I figured if I was going to pay someone to do it, it might as well be a shop that treats you good. By the way Canyncarvr, how do you keep the air out on re assembly?
Oregon Trail
~SPONSOR~
- Aug 2, 1999
- 263
- 0
Most local shop that do repair can do the shock too, I forgot about that. Also if you do it yourself a lot of repair shops have nitrogen. I think I pay $5-10 for a fill in the rear shock. I just follow my KDX manual step by step and it's not that bad, easier that you think.
I recently sent mine to shock therapy in CA, they had good turnaround time, and it was around $175 for a typical rebuild. not sure what all they did but all the oil had leaked out and the shock had no compression when I sent it to them. i beleive they have a website but I cant remember what it is..
BadgerMan
Mi. Trail Riders
- Jan 1, 2001
- 2,479
- 10
I have done my own oil changes for years and it is quite easy, especially on the KDX shock since it has a bleeder bolt on the top of the shock body. The most critical part of the job is to get every bit of air out of the system when reassembling. I use Mobil 1 synthetic ATF (about 7.5w) for fluid and about 160 psi for a charge pressure. The action I get with the Mobil 1 is excellent.
Use a piece of broom handle with a 3/8” hole drilled in the center (to clear the charge valve) to tap the reservoir cap in when removing the clip. Be sure to take some emery paper to the clip grooves before pulling the reservoir cap/bladder and the rod/piston assembly out of the shock body. Otherwise, you may ruin the seals and have an oil leak when you reassemble and charge it. Be extra careful when reinserting/reassembling the clips. You don’t want the cap or rod assembly coming loose when the shock is charged (high velocity projectile)! Some dealers won’t charge shocks they have not assembled for this reason.
If you disassemble the piston assembly (not necessary for a simple fluid change) be sure to note the assembly order of all the components and shims!
Your KDX service/shop manual tells you nearly everything you need to know to do the job.
Incidentally, I charge my shock with plain old air from an ATB shock pump instead of nitrogen. The only possible adverse effect is corrosion on the inside of the reservoir cap due to the moisture in the air. To date, I have noticed no such problem. Absolutely no difference in action from a nitrogen charge.
Use a piece of broom handle with a 3/8” hole drilled in the center (to clear the charge valve) to tap the reservoir cap in when removing the clip. Be sure to take some emery paper to the clip grooves before pulling the reservoir cap/bladder and the rod/piston assembly out of the shock body. Otherwise, you may ruin the seals and have an oil leak when you reassemble and charge it. Be extra careful when reinserting/reassembling the clips. You don’t want the cap or rod assembly coming loose when the shock is charged (high velocity projectile)! Some dealers won’t charge shocks they have not assembled for this reason.
If you disassemble the piston assembly (not necessary for a simple fluid change) be sure to note the assembly order of all the components and shims!
Your KDX service/shop manual tells you nearly everything you need to know to do the job.
Incidentally, I charge my shock with plain old air from an ATB shock pump instead of nitrogen. The only possible adverse effect is corrosion on the inside of the reservoir cap due to the moisture in the air. To date, I have noticed no such problem. Absolutely no difference in action from a nitrogen charge.
BadgerMan
Mi. Trail Riders
- Jan 1, 2001
- 2,479
- 10
There’s no performance advantage. You won’t notice the difference between 140 and 160 psi (most bikes are delivered with approx. 140 psi). However, there is a danger that if the pressure is too low (something <140) that a large impact could suck the seal head up into the shock body and damage either, or both, pieces.
I run 160psi because it was recommended to me, it works, and it provides a little added security over the factory setting. Some guys recommend an even higher setting but I question the benefit.
It’s really great if you can learn to DIY ‘cause then you can change fluids when it’s needed instead of when it’s convenient. You’ll have better performance, less wear on the shock body and internals, and you’ll save a bunch of money.
I run 160psi because it was recommended to me, it works, and it provides a little added security over the factory setting. Some guys recommend an even higher setting but I question the benefit.
It’s really great if you can learn to DIY ‘cause then you can change fluids when it’s needed instead of when it’s convenient. You’ll have better performance, less wear on the shock body and internals, and you’ll save a bunch of money.
BadgerMan
Mi. Trail Riders
- Jan 1, 2001
- 2,479
- 10
All gases have to expand at the same rate when heated (remember PV=nRT).
BTW, the air we breath is 70+ percent nitrogen.
I believe the reason pure nitrogen is used is because it is the cheapest way to achieve a completely dry, high-pressure charge in a manufacturing environment.
BTW, the air we breath is 70+ percent nitrogen.
I believe the reason pure nitrogen is used is because it is the cheapest way to achieve a completely dry, high-pressure charge in a manufacturing environment.
