How to Derestrict a Yamaha DT 125 X/RE

Doing this will greatly improve your acceleration and top speed. I think the method works for the X and RE models as they both have the same speedo. To improve performance even more, I recommend getting a full exhaust system as there is also a restriction in the stock expansion chamber. To see what it's like when derestricted, check out my top speed video :)
Song:
Venemy & BH - Stay Strong

[@user-zm8ft7er7l]

Thank you from the video!! I did it on my own 125 re and I earned GREAT power- max speed before 108 km/h and Know 125 km/h with yamaha exaust not dep!!!!!! The bike is perfect now!!! more than 4 hps from 5000pm utnil the end

[@AlanJayCathcart]

babis xatzakis did you have to change the jets not to kill the engine?

[@A-Z_Motorcycles]

Holy shit bro i didnt no about this and now my bike is absolutely rapid well over 80mph

[@shanejones1882]

I have a dt125re on a 2007 and it only gets to about 54mph flat out it's fully restricted never been touched if I was to earth the wire would it be fine to keep the original exhaust still being restricted till I had the money to buy a dep system?

[@darringoodbrand6603]

Hi mate have you still got a video of how to add a rev counter three looking at your link and it's saying no video ?

[@darringoodbrand6603]

Is there anyway of adding a rev counter to the dt125re think every 2stroke should have a rev counter and temperature gauge but think it was the 05 model they just put on a Speedo and indicator lights that's it

[@mark19850304]

hy,i have a Yamaha dt re 2004,with Gianelli exhaust,if i do this green wire earthing and dont change the carb jets size,is still gonna be ok?or it kills the engine??my problem is that I feel like the powervalve opens late only in high rev,will this cable earthing help me?thank you

[@williampersson9430]

hey! what size is it on the rims and size on the tires? thanks for answers!

[@fredflintstone2077]

That wire was not connected to anything before you removed it? Three wires in top plug and an empty slot the would connect with the Black-Green wire (not Green-Black as you keep typing).

[@englandstillhasit]

So you just snip a wire then add extra scrap wire just to reach the bolt and be earthed? Nothing else.

[@RedLineRevsRLR]

That's it buddy :)

[@reeceperry11]

I have done this it's great thanks I've got a dep system on the way should be good thanks for the fast reply

[@RedLineRevsRLR]

+reece perry No problem mate, the dep make's quite a difference as well :)

[@reeceperry11]

+RedLineRevs I can't wait should be great

[@amerism4530]

how do you do this on a 2001 dtr?

[@spoetnik1494]

How much kw/hp

[@borntobebald]

I have a dt125r from 93. Will it work here to? Can you make a before and after video, to see the improvement? 😃

[@maxxx5798]

No it only works for later models which are called de06

[@dan1ukdsjn]

did you pull the green and black cable from the plug or did you cut it?

[@RedLineRevsRLR]

+Dan1ukDSJN You should be able to totally remove it from the plug. That's what I did.

[@tougedrifter123]

Very useful vid man, what kind of mileage are you getting now vs restricted mode?

[@RedLineRevsRLR]

No idea what it's like restricted but I assume it would be better than derestricted.

[@ablblblb]

Great video! Do you know if this bike has any other restrictors and where?

[@RedLineRevsRLR]

+Jan Z There's a restriction in the expansion chamber. Some people cut it open and remove it but it's better to just get a new aftermarket one. There's also a restriction on the intake manifold that sits right on top of the reed cage. Apparently it only directs airflow to one side of the reed cage. So some people totally cut it off but others (including myself) just cut part of it away so that it directs air onto the reeds evenly. You can see what I mean here: yamahaclub.com/forums/topic/28337-dt125x-reeds-and-carb-jets/

[@ablblblb]

+RedLineRevs Thanks. Do you know how much faster it goes after it's completely de-restricted? Also, what's the fuel consumption on yours?

[@RedLineRevsRLR]

+Jan Z It will probably vary slightly from bike to bike but you should be able to get a 0-60 of about 7-8 seconds and it will be very noticeable. I honestly have no idea about fuel consumption, I just fill up when the trip metre gets to 80 and then reset it.

[@ablblblb]

+RedLineRevs So every 80 miles you fill how many liters on average?

[@RedLineRevsRLR]

+Jan Z About 7 litres maybe, not sure tbh.

[@proelitjump1355]

Im guessing the older models like 86 or 88 dont have this right?

[@maxxx5798]

Right

[@kkona7438]

my dt x goes only 100km/h. It has dep full exhaust, 32mm mikuni with 220 mainjet and i have done the derestrict

[@peterlustig3297]

kärpänen22 220 main jet is too less. I drive gianelli full exhaust and have a 270 main jet you should use a 270 too or maybe bigger

[@RiccardoBellamio]

Hi! I'm sorry for my english, I'm italian and i don't speak english very well... Where did you buy your dep exhaust system? Thank you!

[@RedLineRevsRLR]

+Riccardo Bellamio It was actually on the bike when I bought it but you can get the full system from here: www.adrenalin-pedstop.co.uk/p/Yamaha_DT_125_RE_X_DEP_complete_sports_exhaust-581.aspx That's for a 2004 - 2009 model, if you have a previous model then you need this one: www.adrenalin-pedstop.co.uk/p/Yamaha_DTR125R_DEP_complete_sports_exhaust-580.aspx

[@RiccardoBellamio]

+RedLineRevs , thank you very much!

[@RedLineRevsRLR]

+Riccardo Bellamio No problem :)

[@RiccardoBellamio]

+RedLineRevs for you, is dep exhaust system better than arrow or giannelli exhaust system ?

[@RedLineRevsRLR]

+Riccardo Bellamio The arrow front pipe doesn't look very good but the giannelli looks quite good and sounds good. I thought about getting a giannelli to replace my dep but the dep is way more popular and proven to give good power gains for a dt125 so I just stayed with the dep.

[@viken9670]

Hey i have a DT125R 07 i bought used, and checked if mine was restricted, but the cable was cutted and not earthed. I get around 75-78 mph but it feels like the motor wont do max. Any tips or help?

[@RedLineRevsRLR]

+VikeN Earth it and see if you notice any difference. If you're getting 78mph I doubt it's still restricted. But I can't see how it can be derestricted if it's not already earthed somewhere on the bike.

[@viken9670]

The guy i bought it from have cutted it so its like 1cm long, but il try to earth it. And the "extension" cable is just a normal cable or?

[@RedLineRevsRLR]

+VikeN You could use any type of cable but I'd recommend using some single core cable as it'll be neater.

[@phgoil]

My DT has a good acceleration from the low rpm but from a certain point on it just gets louder and missing the power in the high rpms. I've got the cable like in the video and just recently cleaned my ypvs. Also I've got a complete Athena system. Anyone got an Idea what could be wrong?

[@lewisodonnell234]

Have you tryed keeping the power valve in the open position? I don't know much about it but it sounds like you have the opposite to having the ypvs pinned open

[@2strokemxclassics]

check the servo cables for wear and stretching sounds like your powervalve is set up wrong,it may be set to wrong an opening to much at low revs then at higher revs its closing and losing power

[@marinmarinov6922]

Is that going to work on xt125 x ? Cheers matey

[@RedLineRevsRLR]

I don't think it would mate, they're pretty different bikes all round.

[@millerhopkins8134]

it stops the bike reving over a certain rpm this is on the dtre and dtx 04-08 earlier bikes had different restrictors

[@darringoodbrand6603]

I earthed the wire and put on a full Dep exhaust could real a big difference i can get 75 - 80 in 5th go in to 6th it won't go any faster just wandering if there was any other restrictions??

[@RedLineRevsRLR]

No pull in 6th gear sounds like a jetting issue. If you have just added a less restrictive exhaust, you will likely need to get a bigger main jet to replace the one in the carb at the moment. btw did you remove the snorkel from above the intake box? I tried that but noticed that the bike wanted to bog more and it also has less pull in 6th as well.

[@WolfgangPassAuf]

Maybe you still have a 80 kph restriction?

[@darringoodbrand6603]

My dose 75 mph mabie 80mph but would take ages . it will go straight up to 75mph up to 5th no problem 1s in 6th it want go much faster I had a 1996 dt125r and I could get 95mph no problem but I don't know what mods the guy b4 me did

[@RedLineRevsRLR]

Take the bike to a motorcycle dyno tuning place, they will be able to tune the jetting perfectly for you and it will probably get rid of the problem.

[@jamesoleary8617]

will this work on a tdr 125 ?

[@RedLineRevsRLR]

+James Oleary I'm not sure mate. I think the pre 2005 dt's have a different way of derestricting than the post 2005 dt's so seen as the tdr is an earlier model than the DT125X and RE, It might be closer to the method used for the DT125R.

[@tomasosso3615]

Will this on the dt 125 model 95??

[@dersaftige237]

no there are other restrictions look here but its in german. yamaha-dt-125.blogspot.com/p/entdrosseln.html

[@darringoodbrand6603]

all iv done is the exhaust and the earth mod I was going to try putting bigger cab jets on I haven't touched the air box iv OK acceleration in 6th just when it flat out in 5th up in to 6th mabie get 2mph faster

[@RedLineRevsRLR]

If it's not to the point where you're almost loosing speed when you change up into 6th then it's probably because that's just how the bike is. 6th gear in a 125cc is never gonna have much pull anyway, it's just to be able to cruise at a slightly higher speed.

[@RedLineRevsRLR]

You still may benefit from getting the jetting properly sorted though.

[@reeceperry11]

will this work on the 2001 model

[@RedLineRevsRLR]

+reece perry I think it's a different method with the pre 2004 dt's. I have heard some things about there being a reeds valve inside the speedo housing but I'm not really sure tbh. It might be worth asking on the Yamaha owners club forum, you're bound to get a response there. yamahaclub.com/forums/forum/32-yamaha-dual-sportoffroad-bikes/

[@RedLineRevsRLR]

+reece perry I've just seen this as well... To remove the speedo restriction take off the headlamp cowl and pull out the spring clips holding the speedo in. Then unscrew the speedo cable and lift up the clock. You will see two things in the bottom of the clock casing. One is round and is the light bulb for the clock, the other is white and oblong. This is the reed switch and you carefully prise it out and tuck it to one side out of the clock. I suggest you put it in a bag and tuck it as far away as possible. Do not cut or disconnect it.

[@funnyblackmans]

Does it matter where you earth it or not ? Cause i got one of these bikes off someone and they had the wire connected to the top of the forks area. The bike wouldn't go over 63 mph. If it didn't matter where it was earthed to then my bike probably needs a top end rebuild. Nice video anyway thanks, cause I couldn't find this wire for ages after reading about it on forums, but with a video I found i straight away, thanks.

[@RedLineRevsRLR]

[phone] If the bike won't go faster than 63mph, it's definitely restricted. Some places will be better earth's than other places. I've had no problems with where I earthed it in the video so I recommend doing it there :)

[@funnyblackmans]

+RedLineRevs The annoying thing about the bike is the lack of a tach, but from from what my friend said to me before about "it sounding like I change gear too early". It makes me think the that the cable wasn't actually earthed so the engine still had a rev limiter, Although the revs wouldn't sound weird like they're being limited, the bike would just lose any pull it had. But yh I earthed it to the radiator mount now so hopefully when I've finished my top end (+break in) it can tell me something.

[@RedLineRevsRLR]

[phone] I had a tacho installed on mine before I derestricted the bike and I noticed that the bike would behave like it was near the rev limiter at about 7k rpm but the actual redline for a dt is 10.5k and it will rev all the way to 12k. If you have just now successfully earthed it you will notice a difference straight away as you have so much more rev range to play with. As you mentioned it, here is the video about adding a tacho to the bike: kzbin.info/www/bejne/ooSqXmZoasyBn8U

[@darringoodbrand6603]

the dep exhaust leaftet says that u might have to up jet I cab

[@RedLineRevsRLR]

Yeah I would do that, you don't want to be running lean, you could seize the engine. I'm running a 250 main jet and my bike runs fine.

[@jordanscrase]

Would this be the same on my DT 125 R 1996?

[@dersaftige237]

no there are other restrictions look here but its in german. yamaha-dt-125.blogspot.com/p/entdrosseln.html