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lack of power dt125


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I'm guessing the new DT is a fair bit different to the old one but I bought a brand new DTR125 when they 1st came out (a long time ago) and with the power valve locked fully open, the huge washer with a tiny hole in it removed from the exhaust down pipe & a KX 250 tail pipe just for the noise it would reach an indicated (by a mate in a Fiesta XR2i) 95 mph ! :D Ok it was down hill with my chin on the tank and probably no more than 85 real speed but a massive transformation over standard when it would struggle to reach 60 mph. :angry:

Sound like there is one hell of a restrictor in the new bikes if it won't pull above 50 ? I would have to look at the exhaust 1st & power valve if they have one 2nd then keep my eye on the spark plug colour in case the mixture needs adjusting if any alterations to the above are made. ;)

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absolutely stock this bikes can do 65mph (04 and on) iv never ever struggled to get over 50mph? :blink:

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  • 1 year later...

I've owned a yamaha dt125re 2007 registration now for over 2 years and when it was standard it only did 65-70 mph, But it really felt like it was struggling, So after much thought i decided to go for the dep pipe and the conclusion is as follows

A full dep pipe was fitted, front pipe and the silencer. The carb was opened to allow a much better flow. And the loose wire in the speedo was earthed.

All this has resulted in the bike now being able to do 80mph easilly, and i mean easilly. But have had it to 85 off the clock, but the bike starts rocking at that speed because it's being pushed to it's very foundations. so i stay only at 80mph max which is fast enough in the over taking lane of the duel carrige way.

But it's not only the top end the bike has improved, The acceleration is out of this world, I can do 60mph in 3rd. before i would have to be in 6th flat out to get there. And not only does it get to 60 easilly, it gets there very quicky, 6 seconds maxium, and it just keeps pulling all the way to 80mph. Then will still go to off the clock as i said before.

My mate who had loads of 125cc bikes the list follows a Aprilia RX, Honda NSR, Yamaha TDR, But this will easilly out accelerate those with ease. The dep makes it sound great and has made a massive difference, But the wire that was earthed plays a key part because it now revs to full ability. and doesnt spasam.

I didnt go up a jet size, I kept the standard jet in.

I will upload pics of my bike soon.

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  • 2 weeks later...

I've owned a yamaha dt125re 2007 registration now for over 2 years and when it was standard it only did 65-70 mph, But it really felt like it was struggling, So after much thought i decided to go for the dep pipe and the conclusion is as follows

A full dep pipe was fitted, front pipe and the silencer. The carb was opened to allow a much better flow. And the loose wire in the speedo was earthed.

All this has resulted in the bike now being able to do 80mph easilly, and i mean easilly. But have had it to 85 off the clock, but the bike starts rocking at that speed because it's being pushed to it's very foundations. so i stay only at 80mph max which is fast enough in the over taking lane of the duel carrige way.

But it's not only the top end the bike has improved, The acceleration is out of this world, I can do 60mph in 3rd. before i would have to be in 6th flat out to get there. And not only does it get to 60 easilly, it gets there very quicky, 6 seconds maxium, and it just keeps pulling all the way to 80mph. Then will still go to off the clock as i said before.

My mate who had loads of 125cc bikes the list follows a Aprilia RX, Honda NSR, Yamaha TDR, But this will easilly out accelerate those with ease. The dep makes it sound great and has made a massive difference, But the wire that was earthed plays a key part because it now revs to full ability. and doesnt spasam.

I didnt go up a jet size, I kept the standard jet in.

I will upload pics of my bike soon.

what do you mean open the carb to help the flow mines does bout the same 70 in 4th then il put it into 5th and it just drops powerwise piss like was considering getting a jet kit bt nt sure if it will fix it

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  • 2 years later...

In trying to derestrict my 04 i earthed the CDI cable (which did very little??). Then i tried turning the power valve round 180 degrees - my bike went fron 74mph top speed to 55mph flat out. So turns out mine wasn't restricted at the power valve, but if you're getting 55 out of it tops then i'd recommend turning your valve - worst that can happen is nothing happens, and it's not a hard job, even a novice like me can do and undo it.

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  • Moderator

This thread is long dead mate.

Its over 2 years old. There will be plenty more need help.

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  • 2 months later...
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