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DT125R bogging down in top gear???


KevShek
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Hi all,

ive just got my DT back on the road. I recently bough a 2000 year model which has had the reed valves done, and an exhaust. When accelerating, it fine and goes no problem, but when i change up into 6th gear, the bike no longer pulls in the power band and begins to slow.

If i drop it down to 5th, i can pull away upto 100 kph, but as soon as i got into 6th, it starts dropping speed to 60-80 kph. I feels as if its bogging down. Any ides?

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Has it had the cable behind the speedo earthed?

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Behind the speedo, there are 4 wires.

Blue and black go into the speedo and goto the bulb, however the black/white and red/blue wires dont go anywhere. They are just stick up into fresh air! they dont look as if they connect anywhere, i.e. the end have been cut clean (not frayed)and there are no connections inside the speedo for them. What are they for?

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Ive been reading up,these 2 wires may have went to a reed switch inside the clock, but its no longer there, on the DT.net website, itsays not to cut or disconnect them, but theres nothing the now. Should these wires be connected? are they joined internall in the reed switch and then the circuit cut when it hits 60 mph?

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Ive been reading up,these 2 wires may have went to a reed switch inside the clock, but its no longer there, on the DT.net website, itsays not to cut or disconnect them, but theres nothing the now. Should these wires be connected? are they joined internall in the reed switch and then the circuit cut when it hits 60 mph?

100_4115.jpg

What years the bike? Mine was an 07 plate and there was a cable that went into a connector block with nothing coming out the otherside which was to be either cut and earthed or have another piece of wire coming out the connector block and then earth,

I dont recognise them cables im afraid sorry. :(

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Mine a W reg 2000 year. Well, today i stuck a couple of crimp connectors on those 2 wire and decded to try connecting them. It sems to be working, so my guess is im just gonna leave them connected. It will now go over 60 mph, but i do sometimes need to drop down agear as the powerband doesnt respond well in 6th gear from 7k rpm, ive gotta change up a bit later in 5th to keep it going.

Anyways, it passed the MOT today and the bike is taxed so im all good to go.

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I was thinking today in my lecture about this (was really boring lecture)

Is there any chance you powervalve night need a clean? and/or has it been messed with in the past??

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How do I go about cleaning the power valve?

Tbh I don't know what's been done to the power valve, I don't even know how many previous owners its had! I'm still waiting for my V5 doc. I do know the last owner disconnected the plug to the PV servo thou, and left it open. I've since reconnected it all up.

I have seen the write up on adjusting the PV on dtr.net thou, it looks linda scarey but I'm willing to give it a go.

Can you tell me how much rotation the valve has from closed to open? I've looked at the servo motor and that rotates about 90 degrees when I turn on the ignition. Is that all its supposed to move? Obviously that 90 degree then translate through the cables onto the PV itself.

I guess ill have to take the exhaust off and see how much it moves and if it fully opens. Should it fully open and then close when I just turn the ignition on?

I've noticed while riding, as I'm approaching 7k rpm, it seems to struggle past into the powerband, especially in the higher gears and if there's a head on wind.

Thanks for you help.

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Well, after you mentioned the PV, i decided to take a closer look at it. According to the workshop manual, after youve turned on the ignition, the keyway is meant to line up with the hole behind it, well, min didnt!

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After a bit of adjustment on the cables, and looking up the exhaust port, ive reset the cables and now it lines up on ignition.

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Gonna take a ride out and see how she goes now.

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WOW man! what a difference! The bike just pulls and pulls! theres no hesitation into the powerband now, its smooth and the power is emence! It even pulls well in 6th gear now.

So that all it was all along, plus the speedo wires.

Thanks for the tips.

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Noo problem, it kinda helped i had the same problem with mine as i didnt adjust the powervalve properly after

rebuilt the engine and it felt rubbish, and the hole was miles out,I found the key to working on bikes is to be patient, have a manual, right tools and not panic. It also makes you feel good when something works :lol:

Another satisfied DT owner glad i could help :D

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  • 1 year later...

Noo problem, it kinda helped i had the same problem with mine as i didnt adjust the powervalve properly after

rebuilt the engine and it felt rubbish, and the hole was miles out,I found the key to working on bikes is to be patient, have a manual, right tools and not panic. It also makes you feel good when something works :lol:

Another satisfied DT owner glad i could help :D

Hi guys and gals im new here I just signed up And was wondering if anyone could help me out.

Iv just brought a yamaha dtr125 2003 model and it has no clocks the guy said its full de restricted I have checked the power-valve and thats pinned open and is what i want as i fookin flys through 1234 gears but when i put it in 56 its as-if there is a power restriction to stop me going past a certain speed I have read around here and another person was having similar trouble with something called a reed switch behind the clocks now I dont have any and have looked at wiring and can only find the red and blue wire there is no black and white as well like there supposed to be because he said he joined them both and it solved his problem.

But I had a look today and can find a multi link thing you know the sort of thing that plugs into something eg speedo etc and can see that it has the black and white wire along with the red and blue one but it also has a light blue wire and another colour wire in to it so I assume this is where the reed switch use to go but dont want to take the wires out and join them incase its wrong because there are two more wires in the block thing.

any help would be much appreciated guys as I am new to dt's lol many thanks In advance Ben

oh by the way I can add some pictures if it will help guys

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But I had a look today and can find a multi link thing you know the sort of thing that plugs into something eg speedo etc and can see that it has the black and white wire along with the red and blue one but it also has a light blue wire and another colour wire in to it so I assume this is where the reed switch use to go but dont want to take the wires out and join them incase its wrong because there are two more wires in the block thing.

any help would be much appreciated guys as I am new to dt's lol many thanks In advance Ben

oh by the way I can add some pictures if it will help guys

Just take a short bit of wire and put the appropriate size spade connectors on each end. Use this to connect up the two wires and see how it goes.

Simples!

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