Sigvart's ZXR950R Racer


Siggi's bigbored '95 ZX9R has a new home.

Here's the list of his mods and the bike's spec



Siggi's 950 motor started life in a 1997 ZX7R frame (see other link on the Tuned ZXRs page).
All was well until an accident demolished it. Siggi managed to save a few parts and build himself a proper race bike!
As well as building an excellent bike Siggi decided to do all of the paintwork himself and, as you can see from the pics, he did a good job of it!

Kawasaki ZXR950R
Specifications at a glance:
Some impressions
I bought a set of Mitchelin slicks and I couldn`t belive the difference they made in relations to the Rennsports on stock rims (previously used), and the Rennsports where Great!
First of all the mag wheels made the bike SO much easier to turn, it was as the whole bike felt lighter. This also allowed me to brake even deeper into the the turn, because I could turn in later with out having to "wait" for the bike to turn.
And while I was braking later into the turn, the slicks was keeping the steering neutral. Even when I was braking mid-turn they didn`t caused the bike to "stand up on the brakes", they just kept it in line. And the amount of grip and feedback you get is unbelievable!
I used to spin out the Rennsports when I exited a second gear hair-pin, but it was always a little bit dramatic cause they did hook up so quickly after they did let go. While with the slicks I just felt the rear end "drift out" and slowly get back in line. Needless to say, I was very proud when a friend of mine pointed out that I was drawing black lines out of the hair-pins :-)

Here`s how to adjust your back-torque limiter (Slipper clutch).

I installed the clutch basket with all the accessories on a spare output shaft, that would be the stock zx9 gear tranny which was redundant after the ZXR750R close ratio box went in, then I measured the "clutch free play" and came to 0.45mm (thats`s the distance that the friction and steel plates are allowed to move away from each others to reduce the back torque from the rear wheel) . This is with "not-new" friction plates like it says in the shop manual, but they are not worn out either, just something in between.
The metal plates used are all 2.3mm.

The shop manual says you should work with a free play of ca 0.35 to 0.7, or something, but the Racekit manual says you wanna be in betveen 0.8 to 1.6. So I replaced two of the 2.3mm plates with two 2.0mm plates, making the new free play 1.05mm. And I have another 2.0mm plate laying around for further experimenting.

Later on the kit manual says that that if you increase the clutch free play you are supposed to change the clutch springs according to a diagram showing nothing but colors and part numbers. That didn`t tell me much really. But I figured, if I decreased the clutch spring pre-load by 0.6mm when I reduced the plate thickness, then I could just increase the pre-load by adding +0.6mm washers betveen the springs and the surface they where working against. So I got hold of some washers that where 0.9mm thick and just ground them to fit, figuring the extra 0.3mm thickness would just add some much needed extra strenght to the clutch. That didn`t make the clutch handle harder to actuate, if you are worried about that.


Fuel tank quick release system

Here`s the tank quick disconnect system I`v made, it`s very simple and uses some of the stock kawa parts, at least at the front part of the tank. Do you see how I`v used the metal spacers with rubber bushing? Now the tank is off in five seconds, instead of minutes, if you where to count the search for tools and all... :-)


Because of the new wider triple clamps the front wheel spacing had to be altered. Here's how

If you look at the "Axle Spacer And Nut" picture, then you can see the extra spacer I`ve added to the axle-"head" on the right side. So when I install the axle and push it all the way in and locks it with the allen head clamp bolts, then the wheel is correctly spaced according in relation to the right fork and caliper. The extra spacer is small enough to pass trough the lower fork clamp. This is so much easier than before.
All I have to do now is insert the new (longer) nut I`ve had machined, which will work as a spacer against the wheels left side, also pressing into position against the RH spacer. When I have torqued the nut I have to make sure that the left fork leg is paralell to the right fork leg, which is done by applying the brakes and pressing the front up and down a couple of times, then I tighten the pinch bolts and I`m ready to go.

Because of the wider triple clamps the brake calipers have been spaced in using some solid spacers.

The "New Caliper Bolts" pic shows the new bolts I have made, because the old ones were 5mm too short with the new fork spacing (10mm further apart, remember?) Kawasaki is very keen on using finely treaded bolts, and all I could fine with these treads was bolts with Grade 8 steel. I figured this wasn`t good enough for brake caliper bolts, so I bought Grade 12.9 steel and had the fine treads "inprinted" in them...much stronger, much safer!


Latest news on the 950 engine

After running a compression test on the cylinders, I found that 7 out of 8 intake valves were bent. This gave me compression figures of around 12 kg/cm at best and down to 9 kg/cm on the worst cylinder.
Unless I bent the valves on one of my first rides before I tested it on a dyno, which I doubt very much, then the valves were bent when I bought the engine used. I base this on the fact that the hp figures have stayed the same the whole time I`ve had the engine, and not dropped noticeably like it should have with seven bent intake valves.
So this winter I removed the head and had a valve job done to lap in the eight new valves, which brought the compression up to 16.5 kg/cm on all the cylinders. Job sorted.
Needless to say I`m pretty excited about getting my bike to a new dyno session to see what this tighter engine can produce....

The following Engine information is the same as in Siggi's other page

Pictures and Information on the tuning done:

Phase 1
DynoChart)
Here's a picture of two of my dyno runs. And from what you can see of the graphs, the low down torque and hp is very good. You have to understand that the graph with best high end and worst low end is not really like that....It was one of the last runs so we didn`t bother to feed the trhrottle under 5000 rpm, thats why the graph is a little bit low compared to the other. So at the end, it was the best of two worlds, the best low end and the best high end of what you see on these two runs. 39mm fcr`s is 1mm down from the original cv carbs, so only that fact would help the low end response, if nothing else was tuned. But I also installed Kawa kit-manual carb setting (fuel and airjets, needles and float heights). The dyno runs showed I didn`t miss by much, but it showed a rich spot at the top. A leaner set of mainjets would have given me slightly more top end. We didn`t bother to change the main jets at that point, thought of the cold weather in the fall, but I bought a set of leaner jets to try in the summer. An example, in second gear, at 2500 rpm, I can jerk the trottle (not wide, but close to) open, and get instant pull. At 3000 rpm I can whack it full open, and it just takes off. Let me use wheelies to tell you; accelerate to 5000 in 1st, and whack the trottle open, UP fast!! 2nd gear, 6000 rpm, trottle on-off, UP slow. But the best feeling is throttling hard in 3rd over small hills on the road, and let the negative G lift the front. Let me tell you, I`m not a wheelie fan, but the way the fcr`s controls the engine makes me look good, haha.

Phase 2

Raising the compression
First I checked the cam timing of the stock cams, using a degree wheel on the crank pick-up mount and a travel indicator on the valve retainers I could find the cam duration's and lobe centres. And they where faaaaar from optimum......




Here's a better view from above and a homemade tool to find Top Dead Centre (Made using a long bolt and part of an old spark plug).


Then I removed the head and installed soldering wires (1.6mm thick) on top of the pistons to check the "piston to head" clearance. Kit manual says this clearance should be somewhere between 0.65-0.85mm on a ZX7, and mine was 1.02mm.

To reduce this clearance I removed the gasket between the cylinder rack and the lower part of the engine, this brought me down to 0.76mm, which is a little bit on the tight side for a ZX9, but I decided to try it out.

The pieces of soldering wire should be installed in the pistons in four "clock directions", 12-3-6-9....or in the pistons four "map directions", North-East-South-West.
Bolt on the head with the old head gasket, turn the engine one turn, and unbolt the head again (it`s easy, just the head, the cams do not have to be installed).

You`ll know that you have compressed the soldering wire, because you will feel the crank getting heavier to turn. Or you could just shine a flashlight down the sparkplug hole.
Now you can use a micrometer to measure the piston to head clearance by measuring the thickness of the pieces of soldering wires. If you find the clearance to be 1.00mm, then you can remove the cylinder decks base gasket which is 0.24mm, and you`ll have 0.76 clearance.

Cylinder Head Porting
First I gave the cylinder head a thorough wash before I started rubbing down the inlet ports, and drilled small notches for the epoxy to hold on to.
Nice and clean. Notice the notches in the inlet ports. Roughening up the ports with sandpaper will help the epoxy to take. Also (when the engine is running) slightly rougher ports create more turbulence for the fuel/air mixture hence giving a better burn.
A close up view of the notches drilled into the ports to give the epoxy something to hold on to.
After applying the the epoxy and waiting for about 24 hours I could start measuring the required inside diameters with an "inside caliper", and grind down the epoxy with my Dremel.
Had to be Really careful around the valve pockets, but I got away with it...

The finished items.

Racekit Camshaft & adjustable sprockets
After installing the valves and rocker arms I installed my new Kawa Race Kit intake cam with adjustable cam sprockets and the exhaust cam, which on I had pressed off the old sprocket and pressed on a new adjustable one.

Timed both inlet and exhaust cams to more optimised numbers (top end hp`s), and then re checked that I had done it right...three times...
Also checked that the increased lift didn`t cause the valve springs to go "coil-bound", but no worries there, they checked out ok. (I was supposed to use single race springs, but didn`t have the correct retainers...)

I finally got a chance to take the bike out for a ride yesterday, and it is MENTAL !!!! The increased compression and optimised squish (piston to valve clearance) makes it really "angry", the kit cams really takes off from 5.500-6.000 rpm and all the way to the top, and the epoxy porting works great all over the power curve. I think its the epoxy that now gives me the opportunity to open the throttle in fourth, up hill, at 3.500 rpm, and it still pulls cleanly and strong !!! I haven't bothered to write down in detail what I have done, but if any one ask, I`ll be more than happy to write more about the subject. Oh, and a BIG Thank you to my "On-line" mechanic John Steinar Vivelid, whom I called night and day, and who supplied me with parts and good advice. I would call him Norway's number one Kawa tuner, stroking ZX7`s to 1000cc`s, ZX9`s to who knows what cc`s and building Raptor engines...!!! That's all for now, (will of course run the bike on a Dyno as soon as possible),

Kawasaki Racekit camshaft (intake) with single race valve springs


Ride height to Preload Adjusters
These are my fork spring "ride-height to preload" adapters. They work backwards (wind the adjusters in to reduce preload and vice versa to increase it). The adaptors occupy 15 (or was it 17?)ccl of air, the air gap should be increased to compensate.

Homemade tool to adjust the fork oil level

Updated Dyno chart to follow soon