La Bruta Z1000J

I put a ZX9R on mine. The stem is fatter and I think, shorter than the KZ so I had a new stem machined and pressed into the ZXR bottom yoke. Thats all it took.
You are right that there is a height difference and quite a big one. There is a list floating around somewhere that gives the measurements of a lot of forks (for conversion) but from what I remember,most of the modern upsy dupsy forks are a good deal shorter. A common swap is one of the big Yamahas. The Genesis or exup 1000,I think. Not upsy dupsy but a good length. Its a while since I looked into it.
Now that mine is mounted and the exhaust is on,Im really wondering about the ground clearance. It dosnt look like much and the bike is still on the paddock stand!! I have been thinking that if its a problem,Ill have to try and raise everything .At the back,I could put alloy extensions on the shock mounts and at the front,heavier springs in the forks or maybe even extensions on the tubes. Not ideal but ive put too much into the build to turn around now.

Aha davido I was just looking at your thread since I saw that you've put on a zx9r on! Very nice build and I completely understand now that you've gone that far you can't just turn around everything.

I'm still thinking about it for that reason as well. Two people already told me to check for ground clearance with the exhaust, and see if I won't be scraping sides by having such low suspension. I pushed the forks through the yokes and yes, it was low. Also yes, the stem is at the bottom 7mm different. Z is 28, zx7r is 35. And in general a lot fatter, I think 10 mm overall. I'm definitely going for usd's.

Maybe soon you will be able to tell me how it handles also. So again, I'll be having lots of questions!

Jmartin, that would be the easiest indeed, and I thought about it and asked my "boss teacher" but I'm not allowed to do it by using collars. They are telling me that it is not safe that way. So milling is the only way.

As you are in Belgium,I could give you the contact details for the guy that did mine. A well known Dutch tuner from back in the 70s. Hes just south of Amsterdam. I sent him mine in the post (the original bottom yoke from the Z and the ZXR one.) If I remember right,it was around e150 but I would have to check. The nice thing is that he didnt cannibalize the old one. Just turned a new stem and pressed it into the ZXR yoke.

That sounds great to me. You can definitely give me his contact. It might take a while though and I'm not sure I might have someone locally.

Anyways, do you know how long your forks are? From the middle eye to the top? I've seen a chart with zx9r forks from 94-97 measuring 766mm? Mine are only 720mm

Ill dig out the contact info and measure the forks for you tomorrow.Im in now,the kids are fed and in bed and Im not getting off my arse for the rest of the evening!

Take your time I didn't get off my arse neither yesterday, because I have a lot of time with this project :laugh: Even if its next week it doesn't matter.

Ok, My stem swap ( and the Wiseco kit) were done by Jan Smit of Jan Smit Power Parts.
www.jspp.nl/
The website is a bit deceptive as it seems like just another webshop for motocross parts but Jan has been building and racing bikes and cars since the 70s.His phone number is in there so you can call the shop or him direct ,explain what youre doing and ask him a price.
When I took my engine to him,there was a whole collection of drag bikes i the workshop and a Z1000 with a full conversion (Yamaha forks) and an MTC block.
Anyway give him a try.

I took some measurements this morning and my ZX9R forks (from axle center to top of tube) are 76mm. I have the early model with the
4pot brake calipers. Later models might be a bit different.
I also took the bike off the paddock stand and measured the ground clearance with it standing free.

8,5 to 9cm. Not a lot! Thats twixt the ground and the lowest point of the (Harris) 4into1. 17inch wheels, YSS shocks (same length and mounted at the same angle as the originals )and rebuilt forks with original springs and fresh 10w oil
Then I grabbed my neighbour and got him to sit his fat 100kilo arse on the bike.

7,5 cm!!!!. Ok Im only around 70kilos and Im starting with a monoseat but still,7,5cm is not a lot.I can take it easy over potholes and sleeping policemen when I see them but for the ones I dont see....!! Or If i slam on the brakes....! My 4into1 is going to become a 3into1 very easily!!!!!!!!!!
Bugger. Have to have a thunk on this.
Anyway,I hope this is of some help to you and gives you something to think about.

Davido,
Articles I have read suggest in the neighborhood of 30mm of sag is best. At that setting, you would have to be very careful going over the more well fed coppers.........

www.racetech.com/articles/suspensionandsprings.htm

TexasKZ wrote: Davido,
Articles I have read suggest in the neighborhood of 30mm of sag is best. At that setting, you would have to be very careful going over the more well fed coppers.........

www.racetech.com/articles/suspensionandsprings.htm

Thanks TexasKZ ,a very interesting article. Looks like Im going to be jumping into the world of suspension.

Ok that gives me A LOT to think about hehe. That is definitely a lot of help for me really. Maybe it can become a 3into1 easily but I really hope not.

My forks are only 720mm so that's 4cm shorter! I'm thinking about finding zx9r forks since they seem to be the longest usd's around. I don't have a collector box either for the exhaust system so I might have some more play. I have to double check.

That is a very interesting article TexasKZ I guess I'll be jumping into the world of suspension as well

You should really look around for this list of fork lengths. Its in here somewhere but I dont know where.There may be longer upsydupsys than the ZXRs. Now is the time to find out before you get too far along.

Yup I still have to dig into that a little more to make sure. I already found a few lists, but mainly about suzuki's. There it's the TL which is the longest, but I think still 2 cm shorter than the zx9r. Untill now those are the longest forks I've found numbers of. except ktm, bmw etc, but those are too long. It might take a while before I find the right ones