Dt125 mikuni carb
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Does the later mikuni carbs have a power jet? What does that do? Anyone know where I can find proper pilot jets for a Dt125x? Size 27.5 is wanted.
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You can get ebc brand pilot jets on eBay. They work fine.
The power jet system takes fuel directly from the float bowl via the grey pipe on the side of the carb, often gets blocked and stops working. It’s a bit of a rough and ready system for extra power when the throttle is fully open. -
It’s also worth remembering that carburettors like still air, that’s why the air box is so big, so if you have that strange bottle on the side of the pipe that connects the air box to the carb, it needs blocking as it’s designed to disrupt air flow as a form of restriction.
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Could you link some pilot jets?
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Is is this one?
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Yes that’s the one. l would love to see the maths behind it,unfortunately dtpedia.de doesn’t mention it when referring to the vergaser or carburettor as we know it.
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@Calum is it really a restrictor?
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@irongamer727 Not to my knowledge, the little box on the side of the air box can also be found on the competition bike WR200, they wouldn't restrict a competition bike. At least that's what @AndyYam told me. And he has a lot of experience with all of that.
Secondly, the PowerJet, to my knowledge (Happy to be corrected) is a clever mechanism to lean the fuel off at wide open throttle, when actually you don't need as much fuel.
The logic is that at WOT, you should be easing off the load of the engine and now it's all about refining that combustible mix. The leaner you can run that engine, the better the burn of combustible mix can be.
The trick is to lean it off as much as possible, without causing detonation.
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@glynn123 There are better ways to restrict the bike than some plastic box on the inlet tract lol.
I don't know the science behind it, I figured it would work in a similar fashion to the YEIS. But it's as mystery.
The DTRE also had YAIS as well.
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My Haynes manual says stock pilot jet fit the Dtx is 17.5? What the hell? Thought it was 25.
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@irongamer727 first flatslides came with 22.5 and later models 17.5 and 210 mainjet
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So I was finally able to unscrew my pilot jet for my dtx. It is a nightmare to start now with the Athena kit. I looked in the Haynes manual and it claimed stock pilot jet for the dtx was 17.5.
Mine was a 35! What on earth? How is it possible it is hard to start NOW and not when it was 100% stock?Pilot jet size 35 https://imgur.com/gallery/fS02dV8
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Either way, it is too big right?
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Response please...
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Ask any tuner how to set up a carburettor and you'll get the same response.
It depends on your setup.
Everything from Atmospheric conditions to state of the engine and even altitude will affect jetting.
It's imperative that ones carb is tuned to these varying conditions.
20 years ago, Yamaha spent thousands on designing the perfect carburettor settings to get the DT roughly in the right ball park.
The moment you started modifying the bike, you throw all of Yamaha's hard work out the window.
Just because it had some ridiculous settings on it, doesn't necessarily mean it was wrong.
Jetting should be done to suit, and there is reams of guides on here to help you get the bike in right area.
