SLOW DTR



  • Hey, so bought an 04 dtre which ended up being a pile!! It wouldnt do above 40mph and the powervalve wouldnt work. long story short powervalve now works but bikes gutless until it hits. Full throttle and it's like a moped, then it hits band and takes off like a train. Is this normal, this is my first 2 stroke so not aware how they are meant to be.. it's all standard apart from a dep big one



  • Hi, when was the last time it had a rebuild do you know?could be needing a top end rebuild or maybe the power valve needs adjusting.My dtr125 goes of the clock and it's pretty much standard! It's a very quick bike for a small 125 so definitely sounds like somethings not right with yours. I'm sure someone more knowledgeable will be along shortly who could probably advise better though 👍🏻



  • Also it could just be restricted so you'll have to de-restrict it to get more power there a few guides kicking about on how to do this .. Im sure there's a few restrictions to be taken care of on the newer dt's before you get full power



  • Dont know about rebuilds. I had a shop look it over and they said engine was fine. I don't really want to derestrict it if I can, I had 80 out of it which is plenty. Had a fiddle this morning and it's running super rich, and since powervavle fixed it's chucking carbon out



  • That's good the shops checked the engine over and gave it ok so guess that rules out the bike needing a rebuild then 😃. That's fair enough about not wanting to de restrict it it's probably best leaving it if your getting 80 out the bike that isn't all that bad! When you say carbon are you on about sludge coming out the end can after riding the bike? My bike does that think it's due to me mixing in a bit to much oil since I run premix due to the oil pump failing but if it is I wouldn't worry to much about it as I've had 2 strokes in the past that have done the same.



  • When I got it the exhaust was full of sludge. Cleaned that, since then it chucks out carbon all over number plate, still get sludge build up



  • 04 DTRE should be very nippy and cruise at an indicated 70 all day long.

    It should be quiet and have a slight whsitle to it when you shut off the throttle.

    The powervalve should ne completely operational and in its restricted form it should retard slightly when over 9500 rpm causing the power to drop off drastically.

    There should not be a massive build up of sludge in the exhaust.

    Sorry but if that is the stock exhaust and you have had massives of sludge, or indeed any sludge, then that exhaust needs to be binned!

    Either bin the exhaust. Or derestrict it.

    You can examine the tutorial of how to derestrict the exhaust on here. You will immediately see why I am saying sort the exhaust out when you examine the photos.

    Two strokes have to have a fully working exhaust. When the cat gets clogged up the exhaust will simply fail at correctly scavenging the engine. It will be down on power, waste ridiculous amounts of fuel and burn excessive amount of oil.

    Trust me, the stock re is a fantastic bike. But nothing lasts forever. If you want the standard look then get it derestricted and I guarantee you it will be back up on power. If the sludge is as bad as you say it is. Then that's the problem.

    Examine the photos and it will make sense. Cats are notorious for working perfectly when brand new. Only marginally harming the performance. But when they fail, they take all the power with it.

    I would highly recommend getting an aftermarket pipe. They not only save massives of weight, but will not drop off in power like the stock pipe over years to come.

    If the pipe is not stock.

    Then it's getting too much oil.

    Either incorrect oil pump settings. Failed oil pump. Or the right hand side crank case seal has gone seaping in copious amounts of gearbox oil. Easy way to see the latter is if the gearbox oil significantly drops over s ride out.

    The former will be obvious as it will use up an oil tank rather quickly.

    I highly recommend derestricting the cdi. These bikes are by far the easiest to derestrict and Yamaha want you to derestrict them they are that easy.

    It will be better on fuel and will pull right through the rev range allowing you to really clear the pipes out.

    Remember, theh were designed to be extremely reliable in their stock form. Not restricted form. They were designed to be full power and were restricted as emission laws governed them.

    Claim back lost bhp and reduce your fuel consumption



  • Sadly I'm on learners so don't really want to derestrict it, it attracts too much attention as it is: ) the guy before clearly didn't care about the bike, didn't even have brake fluid in it. It does have a dep big one, was thinking of a gianelli



  • I forgot to add, being first 2t I'm not sure how they are meant to ride, currently it's a bit like having a Turbo, 2-3 sec rev build up and it hits pv.



  • @DevonDtr Yeah fair enough.

    Is it a big one front pipe or dep?

    If its a dep front pipe then sweet.

    It sounds to me like the powervalve isn't setup propeely then. It should be really nippy through the whole rev range.

    I know what you're saying about learner legal but there is no way you can tell if the dtx is restricted or not. The most obvious one is not having the stock exhaust. Which you don't.

    Regardless, sounds like you need to sort the powervalve out.

    Two strokes don't respond like four strokes and definitely feel like turbo cars because in effect they are supercharged by default.

    The powervalve adjusts the exhaust port height which determines where peak power is made. Because it's adjustable it means power cna be made through the rev range. If it's laggy then it's because it is not setup properly.

    Probably because the previous owner knew the powervalve on the restricted models retard themselves after a certain rpm restricting power so they have disconnected it in the fully open position.

    Does it do the cleaning cycle when powered off and on?



  • Powervalve didn't work 2 days ago, it was stuck, it freed itself when I was down lanes and wheel spinning 🙂 it's only got a dep rear, was looking at dep front too but not keen on the chrome, and i would rather spend on getting the bike running sweet.



  • @DevonDtr dismantle rhe powervalve and clean it up. If it's sticking then it will burn out the motor and you will need a new one which will set you back a few hundred from Yamah new.

    So whats on the front, a big one. They are notorious for being cack! A dep is a fantastic pipe, I just didn't like the quality of it.

    The ones to go for now seem to be the stainless steel pedmoto exhausts!

    Mate you're complaining it's slow but not appreciating that all these components need to work in harmony.

    Any one of the components are not working tip top then it will affect the remaining areas.

    Get it sorted and it will be bang on the money for reliability and power. I recommend derestricting the cdi as it is as simple as earthing one wire to the frame and it opens up the rest of the rev range and improves economy at thosr ranges.

    It's a no brainer. It won't affect reliability unless you are utilising the new power every waking moment. It will simply help when you need it most.

    As said there shouldn't be massives amounts of sludge. But I would expect to see some unburnt oil.

    I ran premix and the two stroke oil got everywhere and caked the whole bike in oil!

    But it's a modified engine and I expect that.

    As said in stock form they are nippy both bottom and top end.

    If it's experience lag in the power then it's the servo. And the big one front pipe isn't helping either. If it's the stock pipe and you have had massives of unburnt oil through it then it's going to have damaged the pipe. In which cause either gut it and that will free up lost power and economy. Or get an aftermarket one which will do the same but more.

    Hopefully that makes sense.



  • Not complaining about slowness, just wanted ideas on possible issues. She is booked in for full Carb refurb, pv cleaned, and buying a dep front pipe monday



  • @DevonDtr All very simple things you can do yourself....this is a forum and we can help you.