KZ400 fork mods

Hey all, I am in the process of replacing steering stem bearings on my 76 KZ400, I recall seeing a forum post from I believe Faffi on the Kawasaki twin owners forum- which has seemed to vanish from the internet- on some modifications to the Z400 forks. Does anyone have that information saved somewhere? I remember something about drilling out the holes in the pistons to a larger size and a couple other things but it's been a long time since I saw that post. I also have to do fork seals so now is the best time.

If anyone can help me out that would be great!

Thanks,
Brendan

I wouldn't drill anything! A lot of engineering went into designing the forks on each Kawasaki, so if simply drilling out holes in stuff would improve the forks the holes would already have been drilled out. These bikes were not engineered by amateurs, and Kawasaki had and still has no reason to keep the forks from working as well as possible.

Just clean them up, replace the seals, put in the CORRECT amount of the CORRECT weight fork oil, and ride it. Using the correct weight fork oil will do more to fine tune handling than any drilling you could ever do. If you find the forks too soft you can use heavier fork oil, if you find them too stiff you can use lighter fork oil. Bel Ray makes outstanding fork oil in weight ranging from 2.5W to 30W, and they can be mixed to achieve any weight in between. See www.belray.com/bel-ray-high-performance-fork-oil There's a reason you haven't seen tons of folks suggesting drilling big holes in the forks. ;) Ed
Ed

Best tune your suspension with fork oil viscosity and maybe progressive springs before tweaking the damping unless you really know what the full implications are...

Considering that I have yet to ride this bike, that is probably a better idea. Once it's up to spec and if I feel that it's still not good enough for me then I will look to mods. I know that the KZ400 had complaints of soft front forks even when new but I'm still a newbie to motorcycles so I shouldn't fool with it now.

Thanks for the replies. On a related note, anyone know what happened to the kawi twin owners forum? There was a lot of good info buried on there, be a shame to loose it.

Thanks,
Brendan

The Kawasaki Twins Owners Forum has been down for a couple of weeks now so I doubt it is coming back. I'm bummed because I visited faithfully every morning and read any new posts and welcomed any new members. I spent a lot of time reading through the archives too. There was a lot of good information on that site and while I still remember some I'm sure what I have learned will fade with time. I feel bad for the guys who had long running project threads that they put a lot of time into that are now gone. I had a 7-page build thread for my 76 KZ400 but that pales in comparison to work put in by many others. I'll share the story of that bike here eventually but sadly not in the detail I had recorded previously and no longer remember.

Yep. Put it back to stock get it working well and go from there. That goes for carbs, suspension, ignition, etc.

Too bad about the twins forum. I also had my 400 project thread on there. I stopped going regularly when the site started having issues.

Where was this Twins forum? Nothing is really ever gone once it is published on the Net.

It was located here: kz400.createforumhosting.com/

Dan, I hear you, I read through all of your build threads for inspiration. I hope they can bring that forum back.

Also, I got one fork seal replaced last night, going to try to do the other tonight. (I have an 8-month old Son so by the time we get him to bed and get all the chores done, I might get a half-hour or so at 10:00 PM to turn a few wrenches before going to bed and waking up again at 5:45.... What is the most aggravating is when you spend 10-20 minutes looking for a tool or a part or farting around with a stuck bolt instead of getting any work done!!!) The manual says to use 5w20 oil for the forks, is that still what everyone suggests?

Thanks,
Brendan

I use 15w Bel Ray FORK oil in mine. It works great! Ed

www.belray.com/bel-ray-high-performance-fork-oil

Lord_Verminaard wrote: It was located here: kz400.createforumhosting.com/

(I have an 8-month old Son so by the time we get him to bed and get all the chores done, I might get a half-hour or so at 10:00 PM to turn a few wrenches before going to bed and waking up again at 5:45.... What is the most aggravating is when you spend 10-20 minutes looking for a tool or a part or farting around with a stuck bolt instead of getting any work done!!!)
Brendan

I remember those days LOL. It gets better...
I use Bel Ray fork oil in mine as well.

Lord_Verminaard wrote: It was located here: kz400.createforumhosting.com/
Dan, I hear you, I read through all of your build threads for inspiration. I hope they can bring that forum back.

I'm humbled, sir. I'm just a hack who happens to have kids that are a little older than yours who go to bed on their own so I get a few more hours than you. Thanks.

Lord_Verminaard wrote: It was located here: kz400.createforumhosting.com/

Dan, I hear you, I read through all of your build threads for inspiration. I hope they can bring that forum back.

Also, I got one fork seal replaced last night, going to try to do the other tonight. (I have an 8-month old Son so by the time we get him to bed and get all the chores done, I might get a half-hour or so at 10:00 PM to turn a few wrenches before going to bed and waking up again at 5:45.... What is the most aggravating is when you spend 10-20 minutes looking for a tool or a part or farting around with a stuck bolt instead of getting any work done!!!) The manual says to use 5w20 oil for the forks, is that still what everyone suggests?
Thanks,
Brendan

5-20 is too light. I'd put in 10W and see how you like it. I finally have progerssives in mine now after fudging around with spacers, air chucks etc. There are other things that can be done but I don't canyon carve like I did in my terrible 20's.
I know what you mean about looking for tools. It's like some mean little gremlin A hole is watching me and hiding things I'll need IN PLAIN SIGHT. Look everywhere, move a rag and THERE IT IS. Now I out fox him. I put things back where they belong. :whistle: :lol:
I'm sure everyone goes through that from time to time.
Steve