okay freebie speedo de-restriction

as we know there is a metal disc in the back of the speedo that rotates as the speed increases. when you hit the magic number (about 112 mph) the disc blocks a sensor and introduces the restriction. You can't just unplug the sensor as the ecu looks for a signal at start up which clears as you accelerate and then kicks in again when you hit the number.
If it doesn't find the signal at start up it restricts you to 12500 rpm


there's various ways around it. (m-max box, gold speedo converter, modified ecu etc) I'll not go into the pros and cons here but these generally cost some pennies and/or are no longer available/ or are fairly hard to find.
This way only costs some time (unless you really balls it up although it's unlikely as it's really easy to do! )

whip the clocks off the bike and take the cluster face plate off. (held on by all the really obvious screws around the outside edge of the cluster)

there are four screws that hold the speedo in the main cluster. two of them also hold the speedo cable drive unit on the back of the clocks. Take these 4 screws off and remove the cable drive. Theres a rubber bung where the speedo sensor wires come out of the back of the clocks that also needs to be removed. Unscrew and remove the trip reset knob (turn it the opposite way to reseting it)
once you've done this the speedo should just drop straight out of the cluster. (I haven't bothered with photo's of these bits as it's really easy to do and completely obvious when you have the cluster in your hands.

now if you look in the back of the speedo you should see the following.


the offending metal disc is just behind the tip of the screwdriver.
I covered the miles tumblers up with a couple of layers of thick tape just in case I slipped and then used a dremmel to cut a portion of the disc away.



Give it a good blow through to get rid of all the metal dust so it doesn't cause any problems and voila!

In good old fashioned haynes manual style assembly is the reverse of disassembly.
put it all back together and enjoy ( responsibly within the confines of a racetrack/privately owned testing area ) your bike with it's increased maximum speed.

obviously you do this at your own risk. I am not responsible for you getting caught speeding, putting the screw driver through your hand, destroying your clocks or any of the miriad of others ways you could screw up if you are a complete giffer.

Have you ridden the bike since cutting the disc? I looked at the inside of the speedo and (to me) it looked like the disc triggered the speed light to come on at 80km/h and then when the disc 'ends', that's when the speedo hits 180km/h. I've got a 3EN1 so your clocks might be different to mine. Cutting either end of the disc would either cause the speed light to come on later or the speed restriction to come in earlier, wouldn't it? I could be very, very wrong though. Free information is good though

I'd thought that if the bike revs freely in neutral with the speedo wiring unplugged (which I don't know, I haven't tested it adn I can't find a wiring diagram for the 3EN1), then surely it'd just be a case of fooling the cdi into thinking it was always in neutral by shorting out the neutral switch wiring to ground? It might mean the neutral light was permanently on though

when i looked at this on the 3en i saw it as the speed increases the high of the disc does until it was 'full height' i did think about cutting it off so it never got a signal at all but maybe you're right.... i do have an mmax so i guess i could do it then take it on track and see.... if i have time!

on the 3tj the height is the same all the way round, it works a bit like a switch and by cutting it you just make the switch turn off a bit later.

not sure how the 3en works though

In doing this does the speedo still opperate? Accurately? Ive wanted to derestrict
My 3tj for a while but didnt like the idea of disabling the speedo

I am not sure about this, as you may know I have a 3tj with a 1wg engine yes for real!! It had major running problems. When I had it, but the guy who I got it from said that he deristed by turning the disk upside down! Mine does rev right around to over 15500 revs the one time I did it!!
I also fitted the motrax kph to mph converter to speedo cable which deristricts the top speed and is nice to have mph back on the clock!
I have read so much about deristrion that if ever get a spare £50 I will have the cdi done anyway to be sure it is ignoring all signals that might get or not to cdi.

My bike is I think is a one off with exup removed and straight through exhaust. It idles very badly and does not like going slow but have learnt to ride around it but have wondered if it could still do with cdi doctor.

If your not worried about having extra revs get kph converter from eBay when they come up (must be gold one) otherwise get the full package with the cdi mod.
Mark

thats the thing mines already in mph im sure its british but i cant tell cause its a blummin Q plate haha

bike sounds awesome mines abit of a mash up but only between the SP & RR :) Gotaa LOVE 400's ..when they run properly but thats not the bikes fault :D

I love mine warts and all!! What does it say on cdi? 3tj or something else? Come to that what is stamped on the head stock? I don't know enough about the speedo restriction but it is possible to fit British speedo! I would say if you have a 3tj cdi then it would still be waiting for the "GO" signal? On the road what does it rev to?
Top speed?
Get cdi done, if 3tj piece of mind!!

If the CDI starts with 4DX then it's the official import CDI and won't be restricted.
If you have a 4DX then see if you have an oilcooler, if so it's an official import. The back light and tail middle panel are different too.

If it's 3TJ then it will be. Now check the wires comming out, see if they go into the loom or if theres a M-Max box directly connected to the CDI.
If you have a 3TJ CDI then take the fairing lowers and headlight fairing off so you can check the back of the speedo. A 3TJ will have some wires that connect to the speedo, these need to be connected or the bike won't recieve the 0 kmh signal causing it to restrict to 12,500 rpm in all gears. If yours is a 3TJ with an mph speedo with the wires not connected you can sort it out with a "M-Max" derestriction box, it plugs into the speedo wires.

People forget the restriction on a 3TJ is on top speed at 180kmh (112mph) they think it's a power thing, but if you bodge it then it restricts to 12,500 in all gears. The easiest thing to do with a road 3TJ is fit the KMH to Mph converter at the bottom of the speedo cable, then the restriction is at 180mph so you never hit it.

4dx :) that was a supprise cheeers evil! You know everything sure your not Mr yamaha?