front suspension issue/problem on my 2006

[julianop]

I've had my 2006 for two years. The front suspension has always seemed a bit stiff to me, and the bar risers the original owner put on made it just too difficult for my lazy ass to want to check the settings.

Over the past year, however, I've ridden enough bad roads that the top engine mount bolts broke/fell out, and the middle tabs on each side of the upper fairing where the side fairings connect to it sheared right off (the front tabs were already broken off when I bought the bike, for reasons unknown) and the side fairing pieces started drooping. The upper fairing and the mirrors were shaking around a lot when I'm driving over rough road. Now, I obviously don't ride dirt on this bike - it's just city and county roads, but I get the feeling that the bike is suffering much more from rough roads than I think is reasonable.

I've just replaced the engine bolts & shim, and I've replaced the front and middle broken tabs with four 3/4" x 1/16" brass strap, riveted to the top fairing section, and folded over twice to provide enough thickness to hold the nut plates.

But to the original problem: there is no apparent way of replacing any oil in these newer suspension units. I'm in process of readjusting them, but is there any other maintenance involved? The addendum to the manual shows the exploded assembly, but makes no mention of maintenance. Neither does the owners manual. How do I gauge the integrity of the front suspension?

Any help/wisdom/suggestions, please?

[Furbo]

That - is a bugger.

you have to remove the bolt from the bottom of the fork - its a challenge. I have great luck using an air impact driver, comes right out.

Oddly, most folks, myself included, find the front a bit soft. You might try a lighter iol, or a set of progressive springs.

[cmoore]

I would change the fork oil. If it's never been done it's past due anyway. It could be over filled and that will cause a very harsh ride. Like the previous poster said most riders think the stock set up is too soft me included. I changed to the sonic straight rate springs years ago and they suit me much better. Your fairing fix caught my eye. I've been riding around with broken tabs for way too long. Are pics possible? 

[julianop]

Forks/Oil: well that's the issue, really... these are the later forks, not the earlier ones - that show up in the 94-99 supplement. They have the screw spring adjusters at the top, not the air valves. The manual has nothing on it - the supplement showing only the exploded view, and nothing about adjustment or service. The owners manual discusses adjustment, but says nothing about replacing oil. How DO I change the oil on these rascals? Furbo, are you talking about this later type?

Pics: absolutely! I'll snap a couple this evening, and even put a line drawing together, together with notes. There's a bit of delicate bending of the brass plates to do, but with patience they will come out nicely. I expected the rivets would look ugly, but they actually don't look TOO bad... anything is better than $600 of new Tupperware ;-)

[Strawboss]

Two ways, fast easy way and the correct way. Suck the oil out with a mighty-vac, or get the front end off the ground and take the wheel and forks off the bike, not as bad or difficult as you may think, I did mine, forks off, changed the oil, forks on at a campground last year in about 2 hours total. Get the Kawasaki service manual and a torque wrench. I eventually settled on the .95 Sonic springs and 7.5 weight oil, there are many other options. Lots of threads here about this subject. Its not hard, really, take your time, maybe get a friend to help do things like hold a light or confirm an oil level, spend a nice day and do it, you'll learn and you'll know its done right cause you did it, and after, you'll feel great cause now you've learned how to work on your bike and you'll be wanting to do other stuff. Good luck, keep us posted, don't be afraid, its real hard to mess up.

[Outback_Jon]

With the amount of shaking you describe in the upper fairing, I'd suggest taking a look at the mount that is on the front of the steering head.  It is one bolt that is often loose, and a poorly designed mount that has a tendency to fail, causing the front fairing to drop.  Pull the gas tank and you can see/feel the bolt up on the front of the steering head tube.  It needs to be TIGHT! 

[julianop]

You have hit it right on the head, OJ: I've had trouble with those bolts in the past, and to my horror on investigating this problem I found the right one completely missing and the left one sheared off at the nut end.

I found an friendly neighborhood dealer for my midweeks in Rockford - Hammertime in Belvidere. They are really nice folk, and get orders from Kawasaki for me in two days. I've ordered a complete set of bolts, nuts, washers and shim. Everything came in except the 10x100mm bolt for the left side, and I anticipate that arriving tomorrow or Tuesday. I'll see if there are recommended torque settings for those bolts when I get to

Per a previous request, when I button it all up (hopefully tomorrow evening)  I'll take pictures and post them here along with notes.

[julianop]

So let me also re-post this question... how do I change oil on these newer units? The manual only covers the original air-assisted units, not these screw adjustable ones.

Thanks all..

[Cholla]

As Strawboss said either suck out the oil with a Mighty Vac or remove the forks and dump the oil out the top.

[julianop]

Ah, I see that I wasn't clear on my exact question - my fault.

As I have bar risers, I can't easily see how to gain access to the  top. I can see the damper adjusters, and I think I can see a hex nut down at the bottom.

I presume I take the weight of the front wheel, back out the adjusters, then unscrew the hex nuts? Maybe I'll have to take off the risers to gain access to the nuts.

I have limited resources down at the Rockford house, and will be doing this in a friend's garage, so I'm just looking for as much advance info as I can get. Is there anything special I need for this job?

[enim57]

If you just want to drain and refill no special tools are required, I would recommend flushing the forks with kerosene before refilling. If you want to completely dismantle the forks you will need a tool to hold the damper rod when undoing it. The tool is a 24mm across the flats nut welded to a length of square bar to stop the rod rotating.

Regards, Russell

[datsaxman@hotmail.com]

THREE ways to change the fork oil...

1) Baster method.  I would never put kerosene in there and expect to get it all out.  Not like that would be a disaster, actually...

2) Disassemble, make special tools, lash very heavy appliance up a little higher than I like it...

3) Drill and tap drain holes in the back of the fork legs and install your own drain plugs.  Totally trick.  Took about 30 minutes each side...then another 20 minutes each side when I decided that i really DID need to file a flat on the back of each fork leg if I wanted the little fibre washers to hold the oil.  Took a lot more fork oil to do it twice...30,000 miles with no problems so far. 

saxman

[julianop]

I cannot think why Kawasaki disposed of the drain plugs; not a good way of going cheap.  So that's going to be my next project - after getting my electrics wired up - putting in drain plugs (need for filing a flat section around the hole duly noted).

I got my new engine bolts in this evening, two turns off the preload, and put the Tupperware back on with my home-brew top fairing tabs after taking a couple of phone-camera shots.  The vibration and rattle of the fairings are gone, and I'm a very happy camper. I took it out on the highway this evening and hit three figures - it was glorious 

I'll post the pics shortly.

[SteveJ.]

3) Drill and tap drain holes in the back of the fork legs and install your own drain plugs.  Totally trick.  Took about 30 minutes each side...then another 20 minutes each side when I decided that i really DID need to file a flat on the back of each fork leg if I wanted the little fibre washers to hold the oil.  Took a lot more fork oil to do it twice...30,000 miles with no problems so far.

This^

[Bergmen]

3) Drill and tap drain holes in the back of the fork legs and install your own drain plugs.  Totally trick.  Took about 30 minutes each side...then another 20 minutes each side when I decided that i really DID need to file a flat on the back of each fork leg if I wanted the little fibre washers to hold the oil.  Took a lot more fork oil to do it twice...30,000 miles with no problems so far. 

saxman

This also makes it very easy to experiment with different weights and types of fork oils to see what suits you best. Changing the weight of the oil can make a dramatic difference in the damping characteristics of the front suspension.

I'm at the point where I really need to change the oil on my ZRX forks. Right now the handling is perfect, I would not want to make any changes. But, I'm the third owner of these forks, those that preceeded me were very performance minded. I have no idea whether the springs have been changed or the oil is a different weight from stock. With no drain plugs, I'm at risk of putting something in there that could muck things up. I wish there was a way to forensically determine exactly what oil I have so I can replace it with same.

Dan

[julianop]

Well, if performance is perfect then you could prolong the joy and leave well alone. I mean, don't fix what ain't broke, right? ;-)

[Strawboss]

You really need to get a service manual, it all becomes clear when you look at them especially the Kaw manual. I use the Kaw and the Clymers as the Kaw is more for mechanics and the Clymers to look at the pics for a better understanding of what I'm looking at. Changing fork oil or even taking the forks off is NOT difficult at all, having risers or not makes no difference, same amount of fasteners.

[julianop]

Thanks for the recommendation. I have the Kaw manual, and I just ordered my Clymers online.

[enim57]

I wish there was a way to forensically determine exactly what oil I have so I can replace it with same.

Dan

Take the oil to a company who performs condition monitoring and they may be able to do a test to ascertain the viscosity. It's a simple mechanical test.

Regards, Russell

[elvin315]

Read the Suspension FAQ on Improving the Fork. The last paragraph details the process of adding oil drains.

http://www.zggtr.org/index.php?topic=653.0