Over the last couple of months we have been developing a 99 model ZX9R for good usable street use and the odd race meeting. So here's the result...
Stage one, Power up Kit
The first stage of this, which we term the Stage One Power-up Kit, included a full stainless system, Dynojet carb kit, and K&N filter.
Because Stripper had been behaving lately we gave him enough lead to hang himself and he set about fitting and tuning the kit to suit. As is often the case after setting up the Dynojet carb kit to the recommended base settings he found that there was still some fine tuning to be done. The end result was a larger main jet and richer mixture screw setting.
Then the throttle position sensor was disconnected, advanced and retarded
on 3 separate runs indicating there was no advantage to be had in any position.
the final result of stage one, this test is a fourth gear roll on showing the difference between the standard bike and what it is now.
Stage two, Big Skid Kit
A fair bit more time is involved here as the cylinder head and barrel must come off. Our goal - to improve driveability and performance throughout the rev range without spending excessive amounts of money. The piston to valve clearance and piston to cylinder head clearance were carefully measured and checked to determine how much material could be removed without reliability suffering. The head and barrel were then machined to increase compression, and valve seats cut, re-assembled and flow tested to ensure airflow was increasing not the reverse. Valves were lapped in where required and all was carefully assembled to exacting tolerances.
The final part of this stage required removing the original cam sprockets which are non adjustable and fitting a new set which could be degreed to manufacturer's spec's and were also much lighter.
Everything was assembled, cams were dialled, and the engine bolted back in the frame. On start up you could tell straight away that something was different by the exhaust note, once the carbs were balanced it was into the dyno room to see what the result would be. My own personal feeling was that because the standard cam timing spec's were retarded from what I would normally expect, that its full potential would not be reached. But to my surprise the difference was quite noticeable as the graph shows.
I think there is still a bit more to be had by changing the cam timing, but as we ran out of time and were happy with the result we left it where it was. In the near future we will do some testing with different cam timing settings to see if any more free horsepower can be untapped.
Of course it's easy for me to say it's much better but the proof is in what it feels like from a riders point of view, so here's what Steve Brouggy from Australian Superbike School thought. "You should see what Strippers done to your bike!" was Dave's comment as he handed me the dyno chart " when I asked how one of our ZX9R's that we decided to do some work on was going. "I think you'll be happy," he added with a satisfied grin. I've got to admit to being a sceptic when it comes to improving any motorcycle. Over the course of the years I've seen so many bikes tuned to a standstill, that I like to see it before I believe it. The facts are that the standard 900 puts out 127 HP and the Hindle pipe and jet kit boosted that power output to an impressive 143hp. But.... What I wanted to know was, what's it like to ride....
The standard ZX9R is no slug by any stretch of the imagination, but I have to tell you I wasn't prepared for just how much better this thing was with the minimal modifications done. The biggest difference is how it drives off the turns. Coming out of turn 2 (Southern Loop) at Phillip Island is now the most exhilarating experience I've had while riding a motorcycle. It just keeps on accelerating! The extra horsepower and torque are right across the range, so there's no noticeable surge in power it's just stronger everywhere. (Southern Loop is a fourth gear corner that requires the ability to drive from relatively low revs right through the range before changing gears, so it's important to have flexible power delivery).
The difference is now sort of like this ... a standard ZX9R is like a finely tuned athlete. A ZX9R that's well carburetted with a Hindle pipe is like a finely tuned athlete on steroids! So ... if you find your ZX9 a tad on the slow side (!?!) just try some bolt on horsepower and I'm sure you'll find it more than a little rewarding ... it's just like joining the Chinese Swim team ... you'll certainly have the edge!"
Part II - OK ... so I was impressed by the first upgrade to the bike, how about now that the cams are dialled, the K&N air filter is in and the heads been skimmed a little? I have to admit to not knowing what to expect from the second addition to the bike, but the extra horsepower is definitely noticeable in the fact that the straights definitely are a little shorter than I remember! Unfortunately I haven't had a chance to get back to Phillip Island on it (back to back is the best way to do it) but I got the chance to ride it at a Kawasaki Riders Club ride day at Sandown, and that was certainly enough to tell me that we've taken yet another step in developing the bike. The jump in performance is nothing like the first one, but there is still a notable difference. The main thing that was apparent to me was the fact that the bike now makes power right through to the redline with no discernible drop in power. In fact now it's really easy to be caught out by the rev limiter. One thing it did change was the way the power first comes in, it sharpened it up too much which apparently is easily fixed with a carburation change. It has really highlighted the fact that the handling hasn't kept up with the changes to the engine.
So ... the next mod. is to give the bike to Rod Sharp with the Fox Racing
Shock that I've just taken delivery of ... then we can start to use the
awesome power that's now available. For now we have some schools to do
in Sydney at Oran Park and won't have a chance to finalize any other mods
until the winter break ready for our next 'season'. All I can say is "roll
I'll keep you updated as to the final set-up - and I almost forgot to mention that it will be given to some up-and-coming star to ride at the Stars Of Tomorrow event held at Phillip Island at the end of this year. The boys at AMCN have been given the job of picking the lucky person, so keep an eye out for that.
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