DTR 125r 2000 full jet refurb Advice
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Sounds like a 240 main jet is needed. The easiest way to tell is look at the pilot jet size, if it’s a 25 jet you want a 240 main jet (needle clip a 4th lowest groove) If it’s a 22.5 pilot then you want a 210 main jet...
If your bike has a power valve servo fitted you are wasting low end torque by having it disconnected and pinned open. Pinning open the power valve on bikes fitted with servos doesn’t de-restrict them, as the servo opens the valve fully at higher revs. De-restriction methods depends on year of bike but include:
Pinning open power valve on early bikes without servo fitted
Moving sensor from back of rev counter
Removing tube from inside exhaust inlet on some models
I’m not very knowledgable on later bikes as mine is a late 1988 model that never had a servo fitted to the power valve...
P.S. Congrats on owning a piece of 2stroke history
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210 main jet is fine for the carb, that's even what DEP themselves recommend.
Your problem lies with your powervalve being pinned open. This isn't "Full Power", as SpookDog said, you're just losing out on bottom end.
The problem is, the 2000-2004 DTR Models are some of the worst in terms of restrictions, namely the CDI which is probably why the valve has been pinned.
Your best bet would be to source an earlier 3-RM CDI, or go buy a Zeeltronic/Ignitech aftermarket ignition system which will allow to to fully utilise the powervalve servo
Before you do that however, you need to understand the bikes condition. There becomes a point that after so many rebores, you won't be able to run the powervalve due to clearances with the piston. If you're reaching that limit, then fitting the servo could cause the piston to hit the valve causing catastrophic engine failure.
I believe it's at 2.00mm overbore you need to modify the powervalve to avoid fouling the piston, then there is some overbore after that where running a valve simply isn't possible.
Always Originate, Never Pirate!
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@Calum the UK model is restricted and has a 210 main jet and 17.5 pilot jet as standard. The French imports (as many are) are not restricted and are fitted with a 240 main jet and 25 pilot jet from 1999 onwards. The later DT125RE/X came in 210/17.5 restricted from only.
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@primal-carnage is it a UK or French model as jetting is different for both? Also your model year has the reed switch restriction in the back of the speedo.
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@markus-w I wouldn't say "restricted" at "210". The DEP Pipe is a performance pipe and as I say, not even recommended to up the main jet.
Restricting the fueling is unsafe and dangerous to the engine. It might be that climate favourited 240 main jet. In any event, jetting should be done to suit, and the best bet for nipping performance on those later DTRs lie in the CDI and getting that powevalve working.
Always Originate, Never Pirate!
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@Calum
Yeah, they wouldn’t have separate jetting for restricted and un-restricted models. They all drink from the same cup
The carb bodies are different for year and country (apparently!) and are so jetted differently...I think it’s important to establish the proper jetting for the year of the carb, or the country of origin and year, apparently! They are not all the same base model...
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@Calum yes they have different jetting among many other things. I know you don't have to up jet when fitting a DEP exhaust but to fit a 210 on a French model would be down jetting. It's important to know which model one has when jetting. I've heard people recommend to 'upjet' to a 220 but on a French model that would be wrong.
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@markus-w yeah mine isnt a french import mate so i have orderd the 240 jet with the kit i have tried the 260 and it borked up the road ..but im thinking from a 220 to a 240 will do the job the lad said befor he put the full dep on it was running fine ..i have to say it does run ok but in 1st it just takes 5 seconds for valve to kick in ......i think after xmas ill be putting it in the shop to get valves fixed
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@markus-w now then mate yeah mines not a import mate i only got it last week i just know the carb was rotten so i have sorted that just waiting on fresh re furb kit ...i think a 240 jet will do the job tbh its nbearly there now i get 80 out of it but last gear can take time to kick in
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@primal-carnage What do you mean "valve to kick in"?
You said it's pinned. So it's an open port and therefore the valve isn't doing anything. Do you mean, it takes time for the powerband to kick in?
In which case, as previously said, restore the powervalve to fix that issue. There is nothing to be gained from pinning it, only to lose. This can easily be remedied.
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@markus-w
Cheers bud! Wires can get crossed all too easily with text messages.
Regarding the RH exhaust: Waiting for the man to send it
️ Should be this week 
My bike is actually running really well for the first time! 4000 miles with no head gasket problem!! 
The pipe will be an absolute fuckin bonus!...@Calum
I think he means the power band, maybe? In which case something is drastically wrong! 1st gear should be almost instantaneous. A DTR125 should be doing 60mph in 5 or 6 seconds!...Same old problem with a used bike, you have to set it back to standard. Fix the problem/s, then take it from there...
Check the pilot jet size please bud!...
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