doin fork seals

[extreemthrottle]

i pulled the forks off already, and am going to replace the seals this weekend. i was planning on taking step by step pictures, and if you all like post up in the tech section on how to do it. they really aren't that hard to do except for the top caps with that stupid little clip to get them in and out

i am also doing some other work while i have it apart, pulling the steering stem and repacking the bearings, painting the lower triple tree as well as a steering stop mod for the drag bars that will be coming soon.

let me know what you think

[SandstoneSmitty]

Kewl. I would like to know how to adjust the pressure in the forks. Had Mama Kaw redo my seals a year ago. Now when I hit a pot-hole I get a big banging jar. OUCH! What is the correct PSI for a zl900?

[Overkill]

According to the owners manual standard air pressure for the front forks is atmospheric pressure, maximum pressure is 36psi. Also remember the fork oil viscosity can also have an affect on the damping action of the forks. If your fork oil is old and past it's replacement schedule (18000 miles) get it changed.
Having re-read my original post I can see why it was seen as misleading so have edited it to reflect what is stated in the owners manual.

[zlMark]

i pulled the forks off already, and am going to replace the seals this weekend. i was planning on taking step by step pictures, and if you all like post up in the tech section on how to do it. they really aren't that hard to do except for the top caps with that stupid little clip to get them in and out

i am also doing some other work while i have it apart, pulling the steering stem and repacking the bearings, painting the lower triple tree as well as a steering stop mod for the drag bars that will be coming soon.

let me know what you thinkSounds good! Might I suggest to use the manual as a guide so that anyone following along your doc can also refer to the manual. lots of pics too!


Kewl. I would like to know how to adjust the pressure in the forks. Had Mama Kaw redo my seals a year ago. Now when I hit a pot-hole I get a big banging jar. OUCH! What is the correct PSI for a zl900?Like Overkill said, atmospheric is the pressure, but do it with the suspension hanging

[extreemthrottle]

According to the owners manual standard air pressure for the front forks is atmospheric pressure which is about 14.5psi maximum pressure is 36psi. Also remember the fork oil viscosity can also have an affect on the damping action of the forks. If your fork oil is old and past it's replacement schedule (18000 miles) get it changed.

great info but keep in mind, the volume of air in the forks is very small. i remember my zl1000, i blew the seals out in seconds, not knowing at the time that just "bumping" the air chuck onto the fork would fill it up. you really should'nt have to put air in them.
fork oil viscosity is very important to the dampening to heavy of oil could really make for a rough ride..

[kawboy]

According to the owners manual standard air pressure for the front forks is atmospheric pressure which is about 14.5psi

that would be "0" psi on a pressure gauge

[kawboy]

great info but keep in mind, the volume of air in the forks is very small. i remember my zl1000, i blew the seals out in seconds, not knowing at the time that just "bumping" the air chuck onto the fork would fill it up. you really should'nt have to put air in them. ..

No air (atmospheric pressure) is recommended, but if you want to experiment use a hand pump. As extreem says, an air hose doesn't work well.

[Don Fonzarelli]

I'm looking forward to the pics!
Step by step, one at the time!

[Wstar425]

I had a 550 ltd back in the day with air in front and rear. In the manual it said in GREAT BIG letters to not use an air compressor or it would blow the seals. I bought a little hand air pump from Kawasaki for $60.00???? ( a long time ago) that looked like a little syringe with a screw on tire chuck on the end. No matter what you did you couldn't get it off with out losing all your air pressure. It was pretty much a waste of money, I tried all different pressures and eventually decided that it didn't make enough difference to notice. Of course, I can't feel the pea under the mattress either. I can feel the pee in the mattress.... usually.

The last four bikes I've had the forks off, the oil looked like muddy water. I think you would be better off to first put in new oil, and then maybe mess around with the weight of the oil to try and change the ride.

[zl900_moab]

extreem...lowlife and I will be putting new forksprings in my 900 on Saturday and replacing seals at the same time and we were gonna document the whole thing...But if you wanna, we will just do the fork springs!
moab...

[lowlife]

Oil viscosity/ oil level/ spring preload/ Binding (not likely) If inverted fork travels in the middle of the range of its travel the plushness can be lost. Don't think that will affect our old antiquated system. How much "sit in" do you have?

Air in the forks is only a quick fix for a problem or a quick adjustment. That being said I frequently add some air if I'm planning on riding with some rockets. 5 lbs max for me. Factory is 10w20 I believe and 10 weight being maybe 70 degrees F and below. I have straight 20 weight in mine. Can mix and match weights too. Though I recommend only if they are from the same mfg.

[extreemthrottle]

extreem...lowlife and I will be putting new forksprings in my 900 on Saturday and replacing seals at the same time and we were gonna document the whole thing...But if you wanna, we will just do the fork springs!
moab...

well, i'm alone so the pics are when i get a free hand to take them. feel free to go for it!! i can even add pics afterwards too...
so wish i was putting the progressive fork spring in mine.. maybe someday

[jmac]

No air (atmospheric pressure) is recommended, but if you want to experiment use a hand pump. As extreme says, an air hose doesn't work well.

I have a cheap $10 wally world bike pump some where that works great.Since I couldn't find it last time,I used 12v compressor that is built in to my booster pack.It works good too.I'm a big guy 275lbs,I put about 8-10psi in the forks and 0 in the rear.I think it helps with front end dive when hitting the brakes.It also gives it a little more solid feel.It is there so you can make the bike comfortable for you.So dial here in the way you like.

[AZBones]

According to the owners manual standard air pressure for the front forks is atmospheric pressure which is about 14.5psi maximum pressure is 36psi. Also remember the fork oil viscosity can also have an affect on the damping action of the forks. If your fork oil is old and past it's replacement schedule (18000 miles) get it changed.
I feel quoting 14.5,(or any psi value) as a recommended minimum could be very misleading to anyone seeking information on fork or shock pressures.As stated by Kawboy,Atmospheric pressure is "0" when measured with a pressure gauge.The 14.5 value you stated is a valid number,but is a constantly moving target depending on atmospheric pressure,and temp.(a big difference between 100 deg on the beach and 0 deg in Denver),and has nothing to do with this proceedure.I don't want to come across as a nitpicker,but when I saw that number,to me it was very misleading.
The first thing I would do if someone else had their hands on it and it was stiff would be to make sure it had NO pressure in it.If that was not the case I would change to lighter wt oil.

[extreemthrottle]

well things have definatly made an ugly turn. started on the dissasembly of one of the forks and POW!!!! the bolt on the bottom of the fork that holds the inners together stripped out! not the threads but the allen head part of it. i just spend an hr just trying to carefully drill it out after trying several other ways first. it'll come out, just sucks!! i'm stuck until later before i can get back to it.

[lowlife]

So when I get to the part of the article that says Remove bolt on bottom of forks I should add "unless your name is extreemthrottle then just fast forward to drilling it out. "Yep they can strip out. Always a good time!!!!

[jmac]

well things have definatly made an ugly turn. started on the dissasembly of one of the forks and POW!!!! the bolt on the bottom of the fork that holds the inners together stripped out! not the threads but the allen head part of it. i just spend an hr just trying to carefully drill it out after trying several other ways first. it'll come out, just sucks!! i'm stuck until later before i can get back to it.


If you have some metric allen wrenchs,sometimes you can get those in.(with the help of a hammer)I would think that would be tough to drill out.
Good Luck

[extreemthrottle]

So when I get to the part of the article that says Remove bolt on bottom of forks I should add "unless your name is extreemthrottle then just fast forward to drilling it out. "Yep they can strip out. Always a good time!!!!

thanks lowlife, how'd i know for some reason you'd be the first to break my nutz about this....lol

well i got the head of the screw drilled out fine, so tomarrow i'll get back at it.
i can't even tell you how many forks i've rebuilt over the years, at least 50 or more, and never had one do that to me before. i'll admit i've broken off my share of bolts, this did not want to come out.. wondering if i should use stainless to replace it.

[Overkill]

What is the correct PSI for a zl900?
Sorry there AZBones I was just trying to answer SandstoneSmittys question so I don't know why you feel answering this question "has nothing to do with this proceedure" and having re-read my original post I can see where the confusion arose and have now edited it. What I was trying to say is that atmospheric pressure as a scientific value is regarded as approx 14.5 PSI in reality we would end up setting our forks at atmospheric pressure or 0 PSI at our local position.
We are all trying to help each other out here and I like everyone else am willing to learn and correct any confusion, you really do not need to try and score points against me, this is a great bunch of guys here if it turns into one of those type of sites i'm outta here.

[extreemthrottle]

extreem...lowlife and I will be putting new forksprings in my 900 on Saturday and replacing seals at the same time and we were gonna document the whole thing...But if you wanna, we will just do the fork springs!
moab...


sooooo!? did you do it? i got lots of pics of it and i tried my best to write up a little step by step. i pm'd zlmark about how to post up in the tech section but had'nt heard back yet. came out nicer than i thought. i ended up polishing the fork lowers, painting the upper and lower triple clamp, and polishing the ignition switch cover. starting to look alot better! still got the wheels off of it and i am cleaning them up and putting new rubber on it this week.

[zl900_moab]

It's done, just arranging the last of the photos...Should be up in the next day or 2, Mark and lowlife have done the lion's share of the picture arranging as I am on vacation this week and have not had alot of computer time (finishing my basement!)
Should see it soon...It was kinda fun, and that lowlife really knows his stuff!
moab...

[vinny]

Very good timing MOAB - I am trying to get the ALLEN bolt out of the bottom of the fork leg - but the swine isn't moving!
I will try to get a hex bit driver of the correct size and smack it with an impact driver!
Wish me luck.!

[extreemthrottle]

Very good timing MOAB - I am trying to get the ALLEN bolt out of the bottom of the fork leg - but the swine isn't moving!
I will try to get a hex bit driver of the correct size and smack it with an impact driver!
Wish me luck.!

sounds all too familiar!!! might want to try heating it lightly with a propane torch to loosen it up. i had to drill the head off of mine, but it came out just fine.