Yamaha DT 125 DERESTRICTING
Hello! I have Yamaha DT125 1999 and I want to derestrict it. It has 16t front and 57t rear sprocket and top speed is just around 80km/h (50mph) and in 6. gear it revs up only to 6k rpms.
I have a problem with derestricting. I choose the method with black/green wire that is behind a speedo because I found it easiest, but I can not find any wire that looks like that... There is a mess with those wires and it has anlaser starter so that might be the thing why it is so messy...
- wire that is going from speedo has 6 wires on top (not 3), and the same is on the bottom, and it has some wires that are not in that white block but none of them is black/green...
- which I think that is supposed to be the one with black/green wire, have 5 wires on top and the same on the bottom and neither of them is black/green one…
And there is also this thing...
Its quite a mess so can't really see wires...If anyone knows how to check which is rev limiter wire or something please help...
@Lukas55 the black green wire restriction is on later dt125re and dt125x models only. Yours may have the read switch behind the speedo that needs moving away from the speedo but left connected.
@DTR-NSR Thanks for the answer. I thought that it might be a reed switch... What should I do with it now?
declan last edited by declan
@Lukas55 just search for a de restricting guide
@Lukas55 I believe it's behind the speedo. White plastic block with what looks like a glass fuse. Think it has a blue/red and black/white wire. Just wants pulling away from the speedo but not disconnecting.
@Lukas55 https://yamahaclub.com/forums/topic/16405-dt125r-de-restriction/ This might be helpful
Thanks for your advice. This is what I have under the clocks (pictures under the post) and I think there is no reed switch (maybe it is somewhere but I don't know how it looks), there are just some wires... There is a possibility that someone changed those wires and there is no black/green wire anymore... Please help!
This is under the km/h clock:
And this is under the RPMs clock:
@Lukas55 stolen from the Internet.
It's hard to tell in your pics but is there slot/hole, where the reed switch would be fitted behind the speedo?
Minia last edited by
There is a guide on this forum already. Literally in the "derestricting" sub-forum.
markus.w last edited by
@Lukas55 it is hard to see the picture but it looks to me that just under the Speedo cable connector is the place where the reed switch was, maybe it's there but the wires are not. Try tracing the wires back it may be tucked away somewhere if it's already been done or you may just find the wires had been cut with no reed switch on the end of them (it looks like a glass fuse or bulb) now I understand they shouldn't be cut off because it could cause you problems with the way it runs so maybe that is your problem.
@Minia I know that but there is nothing similar like in my case...
@markus-w Thats what I thought, but there is no slot or anything where reed switch could be...
This is how it looks:
That means there must be some cable but obviously its not black/green because someone changed wires and made mess...
Like there is no white block where wires are supposed to go...It looks like this:
@Lukas55 you first need to work out what model of dtr you have, it looks like it could be a bitsa'. Be worth looking to see what markings are on the cdi and wether it has a 3 or 5 wire power valve servo.
@DTR-NSR I am not sure but I think that 3 wires are coming out of servo...Markings on CDI are a little bit erased so it is not clear what does it say...
Btw what is bitsa'?
@Lukas55 bitsa = bike made up from parts from several different bikes.
It sounds like your bike might have early wiring and cdi. I'd be checking the powervalve is in the open position and the exhaust has had the restrictions removed if it's a original yamaha one. Hard to make out much out from your pics.
@DTR-NSR Yea I know pictures are not great but I can not even see better with my eyes xD. It has some different exhaust I would say that it have yz 125 silincer... Okay so if the black/green wire is going into the speedo it must come from somewhere...
Btw that is 3MB cdi.
@Lukas55 the black green wire comes from the cdi, but your bike will not have the black green wire. It's only found on later bikes 2004/5 onwards. I've got a feeling yours is running about 1998 wiring and cdi. The restrictions in the exhaust are in the front expansion chamber part.
@DTR-NSR So it has only exhaust restriction?