How to get more midrange???

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tosser
Posts: 7
Joined: Sat Dec 05, 2015 5:18 am
My Bike: zxr400......suprisingly

How to get more midrange???

Post by tosser »

Hi guys,
I am soon to build a racing buggy in the 450cc class. Most chaps use YZ450 or KTM 450cc singles. I am thinking outside the square and have bought a crashed ZXR400 H to use the motor. Not having owned a ZXR400 before, I will be relying on your experiences here but I am forseeing the need for a stronger midrange.
What engine mods would you recommend??
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Tirpitz
zxr400 oc member
zxr400 oc member
Posts: 766
Joined: Sun Dec 12, 2010 2:45 pm
My Bike: Kawasaki ZXR400L4
Location: Doncaster, South Yorkshire

Re: How to get more midrange???

Post by Tirpitz »

A ZXR750
ZXR400 L4, purple / black / pink
Hel braided hoses
Pirelli Diablos
Ohlins steering damper
A16 carbon fibre exhaust can
Nitron Sport shock
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Dominik
Posts: 110
Joined: Tue Oct 07, 2014 11:05 am
My Bike: Zxr 400 L3
Location: Trier - Germany

Re: How to get more midrange???

Post by Dominik »

In the 450cc class... :smt017

You can install 440ccm pistons, adjust the timing (earlier inlet open, retarded exhaust close), get some longer bellmouthes for the carbs and a bigger (ram) airbox. This will give you some more power at lower rpm.
All in all the zxr engine isn't designed for midrange power and you will achieve better results if you go for top end...
Zxr 400 SL - 130kg
tosser
Posts: 7
Joined: Sat Dec 05, 2015 5:18 am
My Bike: zxr400......suprisingly

Re: How to get more midrange???

Post by tosser »

Thanks Dominik,
Has anyone tried changing the cam timing? What was your experience??
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Dominik
Posts: 110
Joined: Tue Oct 07, 2014 11:05 am
My Bike: Zxr 400 L3
Location: Trier - Germany

Re: How to get more midrange???

Post by Dominik »

I haven't changed the timing in my bike yet as I don't have adjustable cams (only sp models have those) and changing it by a whole tooth won't work for me.
I know that some have changed the inlet cam timing by one tooth and they achieved more midrange power so you might find something about it here.
Zxr 400 SL - 130kg
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