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Discussion Starter #1
I've just spoken to Kawasaki Germany about the rear shocks and that oil came out of the air valves. No problem. It is possible to change the oil filling
in the rear shocks.

1. Screw of the valves
2. Turn the shocks upside down and drain off the oil.
3. Put fresh oil into the shocks through the opening where normally the airvalve is.
4. Screw on the air valve

Viscosity: SAE 5W (Forkoil is just fine)
Quantity: 142 +- 2,5 ccm
Air chamber: 88 ccm

I will take 10W20 Forkoil to optimize the damping.
 

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Undercover Sportbiker
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After seeing a couple of posts on this, I figured I'd post a link to this page:

http://faq.ninja250.org/wiki/ZX600_shock_oil_change

And here's another, same concept:

http://www.ldrider.ca/techpages/rearshockoilchange.htm


Yes, I know, it's not a Vulcan shock, but the principles are exactly the same. I did not have a syringe for inserting the new fluid so I used a straw (can't remember if it was a coffee stirrer or a wd-40 spray straw) and a container with a very small pouring lip (came with my iron). Worked beautifully.
 

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Discussion Starter #3 (Edited)
O.K done. :pepper:

All you need is this:



1. Screw off the air valve
2. Srew the syringe-tip where the air valve was
3. Put the Damper upside-down
4. Press air into the damper several times an let the oil drain into the syringe
5. When no more oil drains out, the damper is empty
6. Put fresh oil into the syringe
7. Srew on the syringe again an put the oil into the damper. Just pump a little and let the air come out of the damper, then press again, so that the air goes into the syringe

I've used a 7.5 W Forkoil. This shoulb be 50 % heavier than the original 5 W.
Filling 142 - 145 ccm
Ready.
 

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I get used syringes from my vet for such applications. Also come in handy when adding water to batteries (not everyone has MF) or any application when you need precise dispensing.
 

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All you need is this:
Next time I change the shock oil I must get me one of those! Would have saved a lot of work!


I think it would have other good use as well, for instance diluting pesticide/herbicide.
 

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Linkmeister Supreme
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I `ve got a fairly large one from a vet friend, that I plan on using as a vacumn source for the fuel petcock when needed for carb maintenance, etc.
 

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So in the write up from the ninja 250 page they said something about changing the spring. Now can we do just that on ours?
In that write up they are using a ninja600 shock to convert the 250 to a better shock and lower and allow for 2-up adjustability.
Is it that important on ours to change the shock oil?
How much does it hold?
And which weight to go with?
 

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Undercover Sportbiker
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The reasoning behind swapping the shock from a ZX6 onto the Ninja 250 is that the stock shock is only *barely* adequate if you weigh like 120 lbs. The reason for the oil swap is the age of hte shocks being swapped in. The ones that fit are close to 20 years old, and you rarely know how many miles were on the bike it came off of.

I don't know that you could change the springs on the VN, I mean it can probably be done, but you would need some serious tools specific to doing it, so the cost/benefit is prety lopsided. Changing the oil in the shock is a good idea of you have a lot of miles on the bike or want to "freshen up" the rear a little. Of course, how many of us are sensitive enough to be able to tell the difference if the changes are only subtle?
 

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I used to own a 250. It wasn't that bad, even with 2 people. I did think about doing this mod when I had the bike.
I understand about changing the oil. I have about 9k on my bike but it is a 2000 so the oil is old. what weight of oil would be better though? And how much? Cuz the write up is for a different shock.
 

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When I rebuilt my zx6 shock I used Kyaba racing shock oil. No weight was listed on the package, but it seemed fine for my needs. Some people have used fork oil. Your localdealer should have some in various weights - it just happened that the dealer where I was when I remebered I needed it ony had the racing type (small dealer).
 

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So a heavier weight oil would create a stiffer ride?
 

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Is there a way to make the ride less harsh? I thought that was the main problem with our bikes and solo riders.
 

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Is there a way to make the ride less harsh? I thought that was the main problem with our bikes and solo riders.
I`m about 6' tall and weigh #300. I just got my bike last May and have not changed the rear shock oil, but the local Kawi dealer filled them (for free!) with nitrogen to the max recommened pressure of 43 psi. I have the damping adjusters on the rear shocks turned to "4", which is the stiffest setting, and found it good for me riding solo with luggage, or grandkids (#50- 90) most of the time. The Clymer Manual says the factory setting is #2, and suggests that a #150 rider with no passenger or luggage needs only atmospheric pressure. This is then adjusted to personal preference and heavier weights.

Does this help answer your question?
 

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Is there a way to make the ride less harsh? I thought that was the main problem with our bikes and solo riders.
Yes.

Trash the crappy hunks of chrome that the bike came with and get yourself a decent set of shocks from Progressive or Works Perfomance.

Just make sure whatever model you pick allows you to adjust the spring preload. I had a set of Progressive 412's and they made the stock shocks look like tractor springs.


KM
 

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the 412's are the base shocks for our bike too, right? Cuz I saw that there are the 416's and 440's. Unfourntatly I can't swing the money to upgrade right now. Plus when I do the rears, I'm doing the front springs and the superbrace thingy. So I'm gonna be shelling out at least 500 buck to do all that.
 

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And now that I have one of the master's attention, when I do finally get around to changing the rear shock, which should I go with? As far as model and size? Cuz I've seen that there are different lengths. Which I realize will change the bike height to either lower it or keep it the same. I don't think I really want to lower it. I'm 6 foot and I have scraped the drivers pegs already a few times.
 

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you said you HAD 412's, what happened to them? you sell them, they fall off?
 

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The 412's got sold with the bike. (I no longer have that Vulcan 750) and I bought them used from a member who was selling HIS bike. So sorry, they gone.

Those are the "bottom dollar" shocks Progressive makes for our bike. If you rarely ride with a passenger and luggage, do not get the "Heavy Duty" shock.

The stock size is 12.5 inches..this is measured "eye to eye" on the shock. Unless you have less than a 25 inch inseam , stick with the stock length. I would not go taller either as this would alter the steering dynamics.

A few folks have found other shocks they got off other bike models which worked...just as long as they have the same size and mounting bases there is no reason you can't use shocks off something else.

If you plan on doing all that to the front end , it would be a bit of a waste if you don't do something to the rear. If you have a junk yard near you that has motorcycles in it, grap a tape measure and go have a look. You might save yourself 400 bucks.


KM
 

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Oh I'm totally doing both the rear end and the front end. I wouldn't go shorter thats for sure. And progressive doesn't seem to have much listed for taller for our bike. My inseam is 32 so shorter would not be needed. Im not quite sure what you are referring to as far as junk yard shocks. Unless there are some bikes out there that have better factory shocks then ours.

So the 412s would be fine, for the most part, right? I understand the no heavy duty's. I mean my wife and me are less then 50%. and our total weight isn't much more then 315 with gear. And progressive says the Heavy Duty Applications are recommended for bikes that are operated at or near the manufacturer’s maximum load rating over 50% of the time. Our max load rating is what 450 lbs? or more?
 

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Im not quite sure what you are referring to as far as junk yard shocks. Unless there are some bikes out there that have better factory shocks then ours.
I got you to say it here instead of me, LOL.


But yeah, pretty much anything out there that still uses twin shocks in the rear will likely be better than the Vulcans 24 year old/bad design, hell, the 1975 Bonnieville had better shocks.

KM
 
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