Frame Geometry

Need some advice here guys. I picked up a 02 zx12 front end (trees, brake calipers, and forks).the forks are 2" shorter than the KZ forks. So when you add the 17" rim I will bee 3" lower. Is this an issue? How much clearance did you guys loose? This will throw my geometry out of whack unless I drop the back end the same, right ? How do I measure where I am now and come up with a plan of where I want to be when finished? I'm putting a zrx12 rear end on now.

Mark...I can't remember who it was I was talking to Bud,but Yo can get what's called a fork slug insert,that will raise the front end.
Basically,it threads in where the caps are now,and gives You more length.(kinda like a penis extension:laugh: )
ok...not funny,but I know that if I didn't say it,Someone else would have.

I have heard that slugs arent safe. I would just drop the back to match
Scott

Here's a link to a pic of one with USD forks - ground clearance for the pipes might be an issue!?!.

www.kz-fighter.dk/bikes_klub/nils_1000a/nils_1000a_side.html

and, here's a link re: suspension setup which will answer your concern re: your forks being shorter.

inline4.motorrijden.nl/archives/susp3.htm

I originally thought my forks were 2" shorter, they might actually be closer to 3" shorter. Only thing I'm worried about is squashing my header.

Post edited by: Fossil, at: 2006/12/19 02:16

In my ´83 ELR I have ZXR-750 ´91 front, GSXR rear swing and 17" rims. It is much lower than stock. For example with a Kerker 4-1 max ground clearance is only about 10cm / 4". The steering angle (rake?) is OK after mods, no problems, handling becomes slightly faster and sharper. In fact last summer I lifted the rear about 15mm to make it even sharper.

Z1109R Fin wrote:

In my ´83 ELR I have ZXR-750 ´91 front
how long are your forks?

Thanks guys I'll have to diguest this and figure this out.Sandy I saw some of those plugs on ebay new for $100 each.

Post edited by: mark1122, at: 2006/12/21 18:08

There was a rider at Daytona last year on a CB900 that had an offset top triple made that teardropped down to pick up the fork tubes. Didn't look very hard to make. It allowed him to run his tubes lower in bottom triple tree. He added a fork brace to stiffen up the bottom.

the swing arm axle should be in line with a line drew through the drive and the swing arm pivet. Mine is going to be way off(4 1/8"). My old set up was 1 11/16" below.Now what? this will probable put my rake with the zx12 forks around 22 to 23.cant tell since I dont have a tire yet.How tall is a 17/180/55 rim edge to ground?

Post edited by: mark1122, at: 2006/12/26 23:19

Fossil that red KZ looks sweet but there is obviously a clearance issue there.That was a nice project post you put together.Thanks.

Every tire brand is different. A 180/55R17 Bridgestone 002R DOT race tire is 25.2" tall mounted. So just measure down from the axle center 12.6" to get an idea of where the swingarm will be with the wheel and tire mounted.

From your description and picture, you're going to end up with a rear ride height dramatically higher than stock, and a front ride height dramatically lower than stock. Everything you've described so far will work to make your bike handle and perform far worse than stock. My question to you would be: what are you trying to accomplish with these mods? Start with your goals for the project and let's see if there's not a better way to accomplish them.

Thanks Hatman.My original goal was to make it look sweet and stop flexing in the turns.I do not lean it over till the pegs scrape,so I'm sure I can sacrafice some clearance.But I dont want to be worried about taking out my header on bumps.I could probably drop the back a bit(1"?) by moving the lower mounts back.I was thinking of looking into adding forkcaps to pick up an inch? Maybe I could find an 18" front rim to match the back style?If these options fail I may have to look for longer forks?
.
AHRMA20 you said you raised the rear of your z with 4"longer shocks.Did you end upwith a setup like I'm heading towards?Swingarm way below this line?