ZXR400 Restriction

AdamBoyle · Nova Slayer Joined: 29 Aug 2004 Karma :

Hi

In about 5 months ill be 17, so ill be doing my Part 2 bike test (cant wait Very Happy

)... If i can sort out my Aprilia SR ill be flogging that and moving upto a ZXR400 (i hope), my main problem is how to restrict it if the bike doesnt come in restricted condition?

If anybody has any links to some websites that have information on restricting them, or have the information neatly stored inside their head can you help me out?

Cheers!

iCraig · World Chat Champion Joined: 04 Jun 2004 Karma :

Well you go to an authorised dealer and ask them to fit a restriction kit, they cost about £150-200 fitted with all the certification.
FI International make the kits.

Many people on here though decide not to restrict there bikes, but do be aware that this invalidates your insurance and basically means you are riding without a licence.

AdamBoyle · Nova Slayer Joined: 29 Aug 2004 Karma :

mr.z · World Chat Champion Joined: 04 Feb 2004 Karma :

to f1 international.. £200 for a washer and a piece of paper is sickening... there is another way.. find a garrage with a dyno and ask if they can do it for you, it will cost more like £100 and is an equally exceptable way of proveing restriction...

Were about are you? i'm sure somebody iun the vastness of the forums will be able to suggest somewhere reasonably close to you..

However i think we established the many times this has come up the you more likely to be killed by elephants than get caught out, even in a crash, still i wouldn't chance it personally...
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AdamBoyle · Nova Slayer Joined: 29 Aug 2004 Karma :

mchaggis · World Chat Champion Joined: 09 May 2004 Karma :

The way it's usually done is just by restricting the air flow, so the engine simply won't produce as much power. Reduce the apeture on the airbox (big circular washers and things), and possibly restrict the exhaust flow too by a similar kind of means.

Something I just thought about... how does restricting affect the revving capability of the machine? Cut the airflow, cut the rpm? Confused

Frost · World Chat Champion Joined: 26 May 2004 Karma :

It can still potentially rev just as high. the bike is just generally down on power, much like it would be if you were running low on fuel.
Its likely that it will rev just as high as normal in the lower gears however the revs will rise slower. In the higher gears it may struggle to rev as it doesnt have the power to pull the gearing. Which is one of the reasons why you dont restrict a very high performance bike as the gearing is set up for normal power and likely will not react well to reduced power.

Restricting a ZX4 will not have a huge effect on its engine performance or characteristics but it will have a noticeable effect.

mr.z · World Chat Champion Joined: 04 Feb 2004 Karma :

There are allot of 250cc biukes out there worth looking at

zzr 250
bandit 250
and i'm faiiiirly sure there was a zxr 250... Question

loads of em... (many are imported), because they are designed with near 33bhp in mind it will be less of a problem when you put a restrictor in thar..

By the time you'd done two years (and weather your restrictors had managed not to fall out or not) you will probably want a different bike anyways tbh, i dunno maybe not but i would myself...
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chrisb · Derestricted Danger Joined: 05 Nov 2004 Karma :

My son has just bought a ZXR400 I rode back for him untill he had it restricted, this is a high revving performance machine that has 70% of its performance beyond 6000 rpm, its is very quick and I have riden some fast bikes! following the restriction the performance drop was extreme, all the top end accelleration had gone, which is in a 17yr old on this style of bike is life saving. Exactly what its purpose is. This bike is not easy to ride on normal roads, it is designed for track conditions and is limited in its road holding capabilities on uneven surfaces. Its steering is very limited and is very heavy on the shoulders. The rider has to fully consentrate all the time and soon suffers from fatigue. Hey but the bike looks great! Just buy one if you are looking for a commuter!

Chris Laughing

DynaMight · World Chat Champion Joined: 27 Oct 2004 Karma :

Ride a ZXR4 below about 8-9k RPM and thats what it should feel like restricted, After that it will rev but not pull.

IL4 400's will be heavily dependant on high RPMs for most of their power, So will be quite gutless but if your used to a scooter or 125 bike it'll feel faster than a fast thing from fast ville. Then when the restrictions come out it'll feel like a whole new bike and you'll wonder how you ever put up with the restrictions.

Something like a 400 sports is ideal for someone that has to be restricted, wants a bike to last a few years and a bike which is pretty rideable restricted. I have heard romours that the ZXR4 isnt very good restricted, It bogs down heavily and can struggle to get past 90MPH, This maybe a probably with that certain bike though.

I've never rode a sports 600 which was restricted but my ZX6R makes 33BHP at 5k RPM, I'd imagine that would make the bike feel a bit bogged down.

A bike which makes 33BHP as standard is fine if you happy with 33BHP or are happy to buy a whole new bike after your restriction is up.

As you can probably tell, I went the restricted 400 route and never looked back. Although I had a V4 NC30 which has a bit more low down grunt.
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chrisb · Derestricted Danger Joined: 05 Nov 2004 Karma :

Im 17 too and had my zxr400 for the last 4 months. I had the restrictor fitted straight away, which cost £150, with £45 labour for fitting. I rode the bike for the first 2 days without it while it was delivered and the power is emense, especially after a 125, so i feel the restrictor, for me, has made me more focused on my riding skills, and learning about riding the bike.

I can still burn any car on the road by a mile, and keep up with all the bike bikes, it has just lost the responsive acceleration and shaved off the top speed to 100 -110 mph, but im feeling more confident and im sure i would have crashed by now without it!

Basicially i feel that if you are after a 400cc sporsportsbike for a ZXR or CBR, as these are the most reliable, (and i know everyone rates their bike as best) but after i compared it to a VFR (which i despdesperatelyted) it looked bigger, sounded nicer, and looked much more modern, but fit a restrestrictorkeep your insurance valid, and ween you onto the bigger bikes.

NY_Sniper · Trackday Trickster Joined: 20 Dec 2004 Karma :

hi im thinking of getting a Kawasaki ZXr400 but i called a garage up ( only a small firm ) and they said that restricting a large bike can have a major effect on the proformance making the bike shit to ride i would like to know if this is true for the ZXR400 coz i really would love one of these but i will have to have it restricted so i can ride it Razz