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769 Posts
Discussion Starter · #1 ·
[align=center]Destricting the Speed on a CBR250RR(L)
Quick Method[/align]

The CBR250RR models have a speed limiter.

This was the maximum speed before the restrictor signal kicked in....

This speed restriction circuit kicked in and send a signal to the CDI...

The culprit is this optical sensor which detects when the speedo needle gets to the restricted speed limit.

There is a guide to cutting/bending/removing this disc to prevent it ever interrupting the optical sensor, however this requires pulling the instrument apart and takes a lot longer.

So after a bit of investigation, I've found an easier method... stop the signal going to the CDI :D Unfortunately you can't just disconnect the speed circuit, as the CDI defaults to thinking the restrictor is on, which is definitely not a good thing :mad:

So... looking at the CDI under the rear seat...

I've found you can match the expected signal the CDI needs (for restrictor off) using a 3.3kohm resistor to ignition voltage...

Many people have just shorted this Orange/Blue wire to ignition without the resistor, which has also worked. I have only matched the expected signal for the CDI, and for the sake of a resistor, I'd rather do that than test the CDI with anything more simple.

If your bikes RPM is limiting around the 8,000, then it could be that speed limiter circuit is faulty or the wiring has a problem. Maybe the speed limiter plug isn't connected. If so, this will solve the problem. However there are other reasons for RPM limiting... such as blocked jets, low battery charge / failed regulator-rectifier and also leaking carb boots allowing air to be sucked in and leaning out the mixture.

Enjoy the speed freedom :D

· Registered
38 Posts
Eclipze said:
MC19 doesn't have a speed restrictor, other than the operator.
AFAIK all MC22's have the restriction.
Ha ha I guess I'm not going fast enough ;-)

I assumed it was limited because my MC19 instrument cluster has a large "SPEED" bezel hole, though bezel itself has been removed. Also read the maintenance guide by Dos-boy which said all models were restricted. Maybe it was a typo.

· Registered
7,374 Posts
New ninja has 6 gears as opposed to the gpx 5? I know fuck all about kawasaki's but having ridden my mates early 00 GPX, the gears felt very close together and I dont see it happening without a good tailwind.
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