De-Restriction Method #2 - Derestrictor/Resistor Mod

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My Bike: ZXR400L3
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De-Restriction Method #2 - Derestrictor/Resistor Mod

Post by RedexRobB » Mon Aug 17, 2009 1:46 pm

As you will have seen in the previous thread, one of the ways of derestricting is to pick out the little tab. The 2nd way to derestrict the bike is to use a derestrictor box. A number of versions of these are about if you can locate them. Manfucturers include:

-Posh Firm

I dont know of any other companies that produce them, if you do please list them. I do believe that Bats Motorcycles in Biggin Hill sell these at a cost of £100.

As explained in method #1, the CDI is in contant communication with the clocks so that it knows when you hit 110mph (180kmh) by using a tab that breaks a photo transistor, and telling the CDI you have hit that speed and not allowing the engine to rev any higher; giving you more speed. It does this by allowing a small current to flow below 110 mph but when the tab breaks the photo transistor this reduces (or increases i forget which) the current telling the CDI there is a change. We also saw that disconnecting the clocks causes the CDi to jump into a default mode with a restriction of 10krpm.

Now, the clocks can be by-passed completely by the use of a De-Restrictor box. What this does is fool the CDI into thinking that the clocks are still connected to it as well as allowing you to go beyong a speed of 110mph.

As discussed earlier the change in current when the tab breaks a photo transistor is what tells the CDI to start restricting the engine speed. this can be achieved not only with a derestrictor box (if you want to pay out for one) but also a resistor (which is all the derestrictor bax actaully is). the follwing thread show how this can be achieved.

viewtopic.php?f=1&t=7393&st=0&sk=t&sd=a ... r&start=15

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Joined: Mon Jun 03, 2013 8:20 pm
My Bike: zxr400 h1

CDI wiring help for H1 owners with Method 2

Post by tomrowley20287 » Thu Jun 06, 2013 6:09 pm

Hello chaps,

I'm a new owner of a ZXR400 H1 which has been half sorted as a track bike and was limited to 10k rpm with the clocks off.

The loom was half stripped, had no pink wire at the clock end and the wiring diagrams here just confused me.

For anyone that comes after me and has some confusion reading through all the posts and wiring diagrams for an H1 with A type CDI...

The pink wire leading from the 'A' type CDI needs to be wired with a 10k ohm 1 watt resistor in series to either an earth wire if you can figure out which one is earth or the negative terminal on the battery.

This means the the pink wire joins on the end of one resistor leg and the other leg goes to the earth/battery.

Cut the pink wire leading to your clocks if you still have them.

Maplins sell only a 0.6 watt or a 2 watt 10k ohm resistor. The 2watt one works and costs 44p.

Thanks for the useful forum, it's been very helpful.