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Dt125 r poor throttle response / poor low rpm power / great power band ?


krodge1971
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Hi , I'm trying to get my Dt 125 r road worthy after being bought recently , happy with everything apart from there's no bottom end power , not much mid but a huge power band ? .

Surely I can share the power better ?

The previous owner has fitted a full dep system.

Any help would be great .

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Hi Krodge, it's normal forum protocol to introduce yourself in the newbies section mate, that said, it sounds like you have the powervalve pinned open, instead of having a servo fitted that controls the powervalve all the way through the revs, I'm presuming you don't get a deal until around 7k revs, then all of a sudden you get an almighty kick up the back end when it takes off? if thats so, you need to get a powervalve servo and cables and pulley, depending on what year your bike is, dictates which servo you need, up to a 1999 DTR you'll need a 3 wire servo, after that you need a 5 wire one.

If you have a DEP aftermarket exhaust, has the carb been upjetted to suit? normal main jet is usually #210, see if a #240 helps it run better, other than that air filter, new Iridium plug, generally helps out a fair bit, and again depending on your year of DTR there are other restriction you need to sort out, a search in here will help with the de-restrictions for your model bike.

Hope this helps.

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Thanks for quick response Nev .

Looks like more investigation work needed as the power valve seems set up ok from the outside . Servo system fully operational ie it has the "clean cycle" when ignition is switched on . Not yet looked up the exhaust port to see if the power valve is present and correct though.

Thanks again mate .

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Aye whip off the exhaust krodge, and run your finger at the top of the port, the powervalve should be flush with the top of the port if its all set up properly, if not I'm sure theres a thread in here on how to set it up properly, only a ten minute job. but like I said earlier also clean air filter and either clean plug and check its gap, or better still bang a new 'un in, preferbly an Iridium one.

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get the exhaust off as previously said get a torch and shine into port while getting someone to turn ignition on and off see how power valve reacts and at what point it stops at.

most 125 2 strokes dont have hardly any bottom end power, i have to give mine lots of beans to pull away quick but im under the impression that most 2 strokes are like this...

i dont get decent power until about 5000-6000rpm then power band hits roughly 7000rpm up to the line, if i dont give her enough beans on pulling away she struggles then in with clutch twist of throttle then out with clutch and she is trying to get on her back wheel.

dt's are like undertuned mx bikes but are so reliable especially for 2t's - it wont pull your arms off

ken

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Gearing can help but you will sacrifice top end speed,if your just running about town then drop 1 tooth on the front sprocket. But if your over 150lbs no 125 will have any bottomend power so to speak.

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Thanks guys for your input , I'm happy now that the poor throttle response was mixture ( air screw adjusted to suit) then I found it had a 16 tooth drive sprocket which meant pulling off required more revs and clutch feathering . Totally happy now, she's perfect.

Thanks again

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just out of curiosity what sprocket size did you go to?

because im having to give mine alot of revs and feather the clutch!!

gonna have a look at min this weekend whan i get my led indicators on and my winter tyres ;)

cheers

ken

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