speedo/speed restriction

[leopard_pagan]

hehehehe.. i did that yesterday.. copy/paste.
when the mods finally get the help section with all the info that several people have sent in; in place, i can then just post a link.. but no one knows when this section will come live?

[cajun]

Here's a strange question.... I have a chinese "derestricted" box. Took her out the other day and put my GPS lap timer on her to figure out my top speed. Funny thing was that the top speed was...................112.....

But my question is.. How in the hell does the bike know I'm doing 112?!!?!?!? I'm taking into account that the box is worth crap so I'm gonna try the Orange/Blue to positive mod that Greggo did and see if that works. But from my understanding in this post is that if I just unplugged the Speedo it wouldn't let me go past 5000. So I guess that's all the Chinese box did was get rid of that.

Because the bike revs to 13.5k but that feels weird too. Almost like hitting the rev-limiter but not. Like it's just sputtering on 2 cycl. Which I believe that's what the restriction does I think. But the weird thing is that it does it in every gear....

Comments??

[leopard_pagan]

deeeeeep inside your speedo is a light trap sensor. attached to the needle is a disk. while your under 112mph the sensor beam is not broken and sends an "all ok here" signal to the CDI unit.
once you hit 112 the disk cuts the beam and then sends a "not all ok here" this results in 2 of 4 spark plugs to be shut down by the CDI unit.

remedy?
bypass the sensor via several ways
or
remove the disk from inside the speedo **if you do not have patience with stuf.. do NOT attempt this!**

[Cammo]

so I'm gonna try the Orange/Blue to positive mod that Greggo did and see if that works.

That's the easiest way I reckon to derestrict them for track use. It allows you to remove the speedo with no issues.

Do you have a chinese cdi? Best be careful of them if other peeps reports are anything to go by.

[HondaCrank]

inside the speedo is a lig/beam trap switch. a disk attached to the needle inside the speedo cuts the beam at 112mph.
what then happens is a signal is lost/stopped to the bikes CDI unit telling it to cut power to two spark plugs. this signal will continue to be cut all the while you try to go over 112mph. once you drop under it, the signal resumes and the CDI powers all 4 plugs again.
Some times bikes have hic-ups with the limiter. this is often caused by bad by-pass wiring, loose wires or more commonly the fuse for the *dash*, indicators, lights has blown.
when this happens the CDI no longer receives the "i'm here doing my job" signal and automatically shuts down two spark plugs as soon as the bike revs over 5,500 RPM.

there are a few by-passes:
1) remove the disk from inside the speedo so nothing cuts the beam, leave sensor plugged in to loom.
2) fit a Resistor by-pass in the main loom behind the dash, unplug speedo from loom.
3) fit resistor by-pass next to the CDI unit, unplug the speedo from the loom. *cant have the 2 working against each other*
4) if you have KPH reading speedo, fit a manual KPH to MPH converter. your bike will NEVER get to 180Mph where the limiter to send the signal now sits!!
5) a few Ozzy racers have a bodge where they cut and re-wire the CDI limiter wires together...
6) a HRC CDI unit has been fitted....

petrolhead19, i believe you may have number 3, 4,5 or 6 on your bike to allow you to unplug the speedo from the main loom and rev over 5.5K rpm.

If i remove the metal disk inside the speedo would that make the speedo in mph instead of kmph ? I removed the metal disk in my speedo and it doesnt read kmph more like mph, but even then im still not sure its even correct speed. It feels like im doing 40mph and following traffic in a 40 zone and the clock is reading around 20kph

[leopard_pagan]

If i remove the metal disk inside the speedo would that make the speedo in mph instead of kmph ?
> No, the disk has nothing to do with MPH or KPH.

if you want to change the speed reading you have 2 choices.
1) fit a manual converter between the cable and speedo.
2) fit an MPH reading face and do NOT fit a converter.

[HondaCrank]

I thought that was the case, just wanted to make sure it was before i brought a new speedo