Front fork psi

On my KZ550, I notice that my forks are a little squishy ever since I replaced the seals. The air pressure table in the manual says to fill the forks with 7-11.5 psi. But the book also says to lift the front wheel off the floor and fill the forks with about 25 psi without exceeding 36 psi, then let pressure out to my desired pressure. So which is it? Can I start at 25 psi and ride with that depending on how the front end handles? I have 10 psi in it now. And like I said before, it is a little squishy. It doesn't dive hard or even bottom out frequently, But I tend to like the forks a little more stiff. Same with my mountain bikes. I just want to make sure going up past 11,5 is ok. I think 20 psi might feel great.

Is there a way to change the springs to a heavier set to get rid of the air pressure system? And also, when I replaced the seals, I measured 9" from the top of the seals to the bottom of the bottom triple tree. But when I sit on the bike and get ready to ride, the front end sags about 2-3 inches. My seals are in properly. There's no leaking. Just low psi?

We're finally getting sunlight here in Texas after a whole month of thunderstorms. So it's time to ride!

Thanks.
LH

If it was mine I would avoid increasing the air pressure as that may cause a problem with the seals. Instead, I would tune the damping by using different weight fork oil. By adjusting the fork oil weight, you should be able to achieve the stiffness you desire without pushing the air pressure any higher than you already have it.

Have you changed the fork oil recently, and if so, what are you using? I've always found Bel Ray 15w fork oil to work perfectly for me, but Bel Ray offers a WIDE range of different weight fork oil, and they can be mixed to come up with a weight that is perfect for anyone because they range from 2.5w all the way up to 30w. Here's the link:
www.belray.com/bel-ray-high-performance-fork-oil

Also, how did you go about ensuring the fork oil is at the correct level? Some folks measure fork oil using volume (not the correct way) rather than jacking the front tire off the ground, ensuring the forks are fully extended, and then measuring the distance between the top of the fork tubes and the top of the fork oil. The Kawasaki Service Manual should show the correct distance. Ed

Letting out the excess to the desired pressure means the desired pressure within the useable range of 7 to 11.5 psi (not any old pressure below 25 psi). I don't think the sagging is an air issue, but a problem with the springs or low oil. ???

You can replace the springs --- Z1Enterpirses.cm carries them. The manual should have a free spring length table to see if they are within spec. I have seen it suggested that when you get new Progressive. springs, you can eschew the air & I don't think you'd need to get springs that are too stiff.

And as 650ed suggested, don't overlook the oil. The manual for my 650 says to use 10W but next time I'm going use Belray 15W. The Kawasaki 550 service manual should have the correct method of measuring. Some will say with the springs installed, while others without (my 81 650-CSR lists the oil level without spring).

I installed Schrader valves 30 years ago. Big disappointment. I ran heavier oil until I bought my progressive springs. I have 15/W oil in there now and the tire stays on the ground like it should.
Steve

650ed wrote: If it was mine I would avoid increasing the air pressure as that may cause a problem with the seals. Instead, I would tune the damping by using different weight fork oil. By adjusting the fork oil weight, you should be able to achieve the stiffness you desire without pushing the air pressure any higher than you already have it.

Have you changed the fork oil recently, and if so, what are you using? I've always found Bel Ray 15w fork oil to work perfectly for me, but Bel Ray offers a WIDE range of different weight fork oil, and they can be mixed to come up with a weight that is perfect for anyone because they range from 2.5w all the way up to 30w. Here's the link:
www.belray.com/bel-ray-high-performance-fork-oil

Also, how did you go about ensuring the fork oil is at the correct level? Some folks measure fork oil using volume (not the correct way) rather than jacking the front tire off the ground, ensuring the forks are fully extended, and then measuring the distance between the top of the fork tubes and the top of the fork oil. The Kawasaki Service Manual should show the correct distance. Ed

The stock oil is 5w. I went with 10w. I aslo measured the way you wrote it down. Hmmmm. Maybe I can try 15w soon.

Maybe I should get Progressive sprigs as well. Everyone talks about how great they are. Maybe that will be the ticket as well.

LuckyLucOnBass wrote: The stock oil is 5w. I went with 10w. I aslo measured the way you wrote it down. Hmmmm. Maybe I can try 15w soon.

Maybe I should get Progressive sprigs as well. Everyone talks about how great they are. Maybe that will be the ticket as well.

Measure the oil as indicated in the appropriate KZ550 factory manual --- some KZs are done with the springs installed, others without. The oil level will vary depending upon whether or not the springs are installed, so it does matter. I'd guess the 550 is without the springs. just a guess.

Two years ago I replaced the air-ride suspension on my KZ1100 with Progressive fork springs and rear-shocks, and have yet to wonder why...except for not having done it much-sooner.

U Haul trucks, Air Ride suspension, IT STILL RODE LIKE A TRUCK.
Steve

martin_csr wrote:

LuckyLucOnBass wrote: The stock oil is 5w. I went with 10w. I aslo measured the way you wrote it down. Hmmmm. Maybe I can try 15w soon.

Maybe I should get Progressive sprigs as well. Everyone talks about how great they are. Maybe that will be the ticket as well.

Measure the oil as indicated in the appropriate KZ550 factory manual --- some KZs are done with the springs installed, others without. The oil level will vary depending upon whether or not the springs are installed, so it does matter. I'd guess the 550 is without the springs. just a guess.

The manual says to fill the oil without the springs in, using the amount listed in the table. Then compress the forks by hand to circulate the oil. Then fill the tubes to the measured distance from top tubes to the oil level. That's what I did. Hmm. Maybe I can check the level again. I'll look at Progressive springs as well. I haven't heard anything bad about them.

Maybe there isn't anything bad to say except buy a jealous wannabe. :whistle:
Steve