Chassis upgrade F/R

The weakest area of any '73~'80 Kz900/1000 is the steering stem head area and the top frame tubes. You can clamp a stock unbraced Kz frame in a vice, put a 4 foot tube into the steering head, then push on the 4 foot tube, and watch the top frame tubes bow outward!!! All that stock tin plate gussketing below the steering stem is worthless. Cut all that away and replace it with some tubing as in the two photos below. Then toward the rear of the top frame rail make up some triangular bracing that tie those three frame tubes together. You can do it with tubing, or with flat plate welded together to foam that brace. You can see what I am talking about in photo below. All this will keep the steering stem area from flexing. Then you could tie the rear of the main frame hoop together as in the photos enclosed. Then throw away all the stock motor mount plates and bolts, and go with oversized bolts that you have to tap into place on the frame and motor mounting areas. I went with American bolts on my bike, and used an adjustable ream to open up my frame and motor. Make up some thicker motor mount plates as in photo below. This ties the motor to the frame making the motor part of the frame. I have seen many a Kz front motor mount areas where the frame left marks from the frame moving around the motor!!!

Remove all that worthless tin plate gussketiing under steering stem head and replace with tubing.



The triangular brace tying the three top frame tubes together.


This bracing ties the main frame hoop, swing arm pivot area to the steering stem head.



These are the oversize motor mount plates with ream fit motor mount bolts.

Dr. Gamma, what size tubing are you using for the frame braces ? I'm assuming .120" wall thickness ?

kzdcw wrote: Dr. Gamma, what size tubing are you using for the frame braces ? I'm assuming .120" wall thickness ?

All the tubing around the steering stem is 1 inch. If I remember right the wall thickness was .095 or there about.

The other tubing used is 7/8 tubing with 065 wall

I only use 4130 chromoly tubing for all my bracing.

Thank you !

How big upgrade/improvement is upgrading the forks with emulators?

gordone wrote: How big upgrade/improvement is upgrading the forks with emulators?

I went from progressive springs to Race Tech springs and emulators and it was a significant difference. They keep the front tire firmly planted on the ground while doing an amazing job "smoothing" out the road and making the front end far more predictable.

Dr. Gamma I noticed there are no provisions on the frame to mount a seat. How are you mounting one?

kzdcw wrote: Dr. Gamma, what size tubing are you using for the frame braces ? I'm assuming .120" wall thickness ?

.065 is plenty for bracing. hell you could go with .045 chromoly and be totally fine

Move0ver wrote:

gordone wrote: How big upgrade/improvement is upgrading the forks with emulators?

I went from progressive springs to Race Tech springs and emulators and it was a significant difference. They keep the front tire firmly planted on the ground while doing an amazing job "smoothing" out the road and making the front end far more predictable.

I have created a separate topics to avoid messing up these one....
kzrider.com/forum/5-chassis/609902-fork-upgrade-with-emulators

baldy110 wrote: Dr. Gamma I noticed there are no provisions on the frame to mount a seat. How are you mounting one?

I used two 6mm studs threaded into existing nuts on seat pan. Then I fabbed up two plates on the frame tube for the studs to drop into. I have raced the bike with and without nuts on the seat studs. This setup weighs a lot less than all those stock hinge brackets on the frame and seat pan!!!

Thanks

I just ran across these shocks today and I'm really thinking about getting a pair. I love the Ohlins but they run about $900/pr and I don't really trust the $80/pr nitrogen charged piggyback shocks even though they look really cool. Those TEC shocks seem pretty well built.

kevski wrote: To be fair it depends on what you want out of the bike when finished, one of the best improvements is frame bracing, my own has this and it's a very worthwhile modification stiffening up the frame no end, i also have TEC adjustable shocks not expensive around $200 US, on the rear, set at around 270mm eye to eye and this speeds up the steering, tapered roller bearings for the head stock and triple trees stock forks with a slightly heavier grade oil than stock, rear arm is stock with a deep brace added needle roller bearings installed, stock wheels, a cut down seat as i have short legs at only 28 inches, with these slight improvements 40 year old bike handles a lot better than a stock zed