'75 KZ400 Break it Loose!

Starting to look at some seat/tail lines..

Started to foam out the seat. Bike is looking more like a standard tracker than I had originally anticipated, but oh well, I'm liking all the decisions I'm making.

Currently running 14.5" Truxton shocks in the rear, which ended up not giving enough chain clearance at the swingarm pivot.
Have 13.5" stockers from a Bonneville on the way. Will run those with a chain slider on the swingarm as a backup (though I don't see it rubbing with the extra clearance).

All said and done I'll be up 1" in back and about 1.5" up front. I may result to lowering the front the extra half once it's up and running. We'll see how slow it handles. My guess is that once the bike is loaded up, the extra half inch in front won't matter since the rear seems to be a bit stiffer.

I would assume the rear is going to way stiff with Bonneville shocks. Race Tech recommends changing the shock setup if a 20+ pound change occurs from the specified values. You've got shocks from a bike that is 120 lbs heavier and you are trimming fat from your bike. however if you're a big guy (like 240) this would probably be an ok setup. Personally i can tolerate a soft suspension, but a suspension that is too firm is no fun IMHO.

Tail shape is looking nice. might be a cool design feature to extend the bevel that is on the top sides of the tank to the tail.

I may be looking at things all wrong, but from what I'm finding, the stock spring rate on the KZ400 is 1.9kg/mm (per my factory manual).
Spring rate on the stock Bonneville springs is .75kg/mm.
That considered, wouldn't the bonneville springs be, if anything, too light?
I can tell you from the "bounce test" that they're far more substantial than the stock springs..

wow those are super soft shocks from the factory on the bonny. Actually they may be just fine on your bike. I do find it hard to believe the stock 400 has that high of a spring rate though.

New shoes!
Vee Rubber VRM 193 100/90/18 Front and rear.
One of three choices for an 18" dual sport tire that wasn't too wide. I'm satisfied enough with them. Tread for 80% road, which is pretty realistic.

Decided to try my hand/learn to mount my own tires and save some cash in the process. I purchased harbor freight levers for $4 each. Almost wish I had just bit the bullet and gone with the motion pro spoons, but they worked well enough.

Also learned to patch inner tubes in the process
Several times.

All mounted up now though. First time i've had it mounted up with new tires and taller shocks. sits real nice!
Had the wife climb on the back to see if there was enough room for two-up. Was pretty tight, so I'll likely be adding another inch or two to the seat in the fiberglass stage.

Finally had a chance to keep things moving.

Made a plate for mounting the new (smaller) headlight.

Welded up the tail section with steel tube. As the fiberglass cowl will be squared at the rear, so is the tail section.

Frame taped up for glassing. Since I'll have the actual seat pan separate from this, I added a small tray for tools/plugs.

Stage one glassed!

Shaping the tail with floral foam (wear a respirator!)

Glassed in! Still need to dig the foam out, make the seat pan, and make the cowl that will go over the tail to clean things up

Nice work. Makes me want to get going on my XS650 seat...

Damn. This is making me want to reconsider how I did my seat.

dom2570 wrote: Damn. This is making me want to reconsider how I did my seat.

How so?
How'd you do yours differently?

Update on the glass!

Interesting, a trunk?
Steve