zxr400 Rev Limiter

Many zxr400 imports come across the waters with built in restrictors/rev limiters.One known limiter is in the speedo, when the needle spins to a certain point determined by the engine revs a limiter cuts in.

A brief explanation follows,

Firstly remove the speedo from the bike.

Remove the reset knob via the tiny screw in the centre of the knob.Remove the 4 screws on the back of the speedo unit, 2 hold the casing on and the other 2 hold the gear mechanism in situ.

The casing is held on by a metal ring which seems to be pressed together to seal the speedo, you can get a small flat bladed screwdriver and prise all around the ring trying not to damage the ring as you will need to replace it later when you put the speedo back together.For ease of this excercise i cut the ring with some snips and discarded it.Once removed you can prise the glass cover off and remove the rear casing.

As you can see from the above pictures there are 2 contacts (circled), as the speedo spins a small tab which is fixed to the speedo drive mechanism cuts a signal which passes between the 2 contacts and then breaks the circuit, this is what cuts your revs.

The idea is to remove the tab from the drive mechanism, i did this using a small flat bladed screwdriver and gently prised the tab off with very little force.

It is then a matter of re-assembling the speedo unit and away you go.

You can see from the above picture a hole in the side of the speedo casing, you may be able to get a screwdriver through this hole and with extreme care prise the tab off without dismantling the speedo unit itself, If anyone does this please let me know for future reference.But bear in mind this little tab will be floating around inside the speedo and cause more problems itself.

zxrworld will not be held responsible for any problems, accidents or damage caused by anyone undertaking this task, it is merely a theory put into practise

Update April 2007 - this speedo has now been tested and proved to de-restrict your zxr400 a big thankyou to adreid for being our guinea pig.

Thankyou to RobB for the input and ideas and to Coyote for donating the speedo, and again thanks to Adreid for testing it.

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