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When I did Cadwell park in September 2003, I couldnt understand why I was losing
so much time to a mate on his ZXR400, averaging 6/8 seconds per lap! Now he is
a better rider than me as hes got a lot more track experience and has a very
nicely sorted bike but I should have been a lot lot closer than that.
When I got an instructor to follow me, he informed me that I was only achiving
100mph along park straight, I should have been reaching 125mph, especially as
my exit corner speeds were high out of charlies 2.
Laptime wise I was hitting circa 2 min times on the 400 on the full circuit. My
mate was hitting 1:53 to 55's which was dissapointing as I was aiming for 1:55
which I was sure I was capable of, especially as thats what I achive using the
zx6R.
When I got back home, I discovered a few things that didnt help my top end speed
loss:
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Gearing was too high
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Possible air leak at the carbs leaning off the mixture at the top end hence
losing power
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Rear brake caliper was rubbing on the wheel
Gearing
After speaking to a few people, they advised me that the gearing on the
FZR400RSP is was over geared for most tracks. Neil Smith runs various sprockets
ranging from 38-45 for the rear andf a 14 tooth for the front to cope.
I stripped the carbs down and gave them a full cleaning out with carb cleaner. I
did find that the clamps holding the carbs to the airbox were not sealing
correctly so this could attribute to the leaning off of the mixture.
I then by chance looked at the rear end around the brakes & couldnt beleive
what I was seeing. The previous owner had fitted a caliper from an FZR750 &
had filed off the bottom to give it some clearance. Problem was it wasnt enough
& it's actually been rubbing on the back wheel, wearing away aluminuim in
the process! Luckily I had a spare FZ400 rear caliper so swapped it over,
rebled the lines & spun the wheel. About 1 mm of clearance, jeez leave it
tight don't they!
For Anglesea (report), I decided to fit a
14 tooth front sprocket & see what a difference it made. Acceleration was
improved and the bike seemed to respond better to the throttle. Unfortunately
Anglesea has no long straights although I was hitting approx 95mph along the
main straight (in the wet on sports tyres!). The real test would be back to
Cadwell to compare with previous dates, just hope it's dry!
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