samslam2000uk Posted February 17, 2011 Share Posted February 17, 2011 Hello gents, just a couple of quick questions i have about my DT... Having a small issue when accellerating in most gears, she gets up to when the powervalve should be opening (around the 7500rpm mark) and it coughs and splutters, and struggles to get past. The bike has done just over 10,000 miles, and I'm guessing the powervalve may well need a clean? However, Someone has suggested I may need to upjet? If so, what size should the full power jets be? Pretty sure I have the OEM carb on the bike. Also, the random black vacuum box that goes into the carb manifold... whats the purpose? Just out of interest, I have no need/interest to remove it. I'm basically trying to work out if my bike has been correctly derestricted, as I don't want to suddenly land myself with a seizure. all I know so far is that I have a full dep system fitted..... I had a look over the air filter and everything looks as standard, no modding, I've not actually had it long enough to crack open the carb yet, but I may well do that this weekend, to figure out what jet sizes I'm currently running. Is the '03 model affected by some sort of electrical restriction? I've read some threads on here that suggest there is a wire underneath the clocks that needs earthing out? All help much appreciated, Cheers! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 17, 2011 Moderator Share Posted February 17, 2011 First thing to do sam is check that the powervalve is fully opening. Turn on the ignition ant the pv will do the 'swish swish' sound of its cleaning cycle and will then sit in the full open position with the 'U' notch in the pulley aligned with the hole in the head. At this point I think the key can be switched off again without affecting the position. Now remove the exhaust and check the pv is sitting fully open and the top of the exhaust port is a dead smooth passage. see my thread deristricting my DT125r for further info and pictures. There is also a speed limiter installed in the speedo, it will need pulling out and tucking away somewhere (also covered in that topic) The black/green wire thing is not for your bike but for the later elect start model DT125RE Link to comment Share on other sites More sharing options...
samslam2000uk Posted February 17, 2011 Author Share Posted February 17, 2011 Thanks so far OG, now, is this the reed switch? I have also checked the powervalve movement, and when it is fully open, it sits flush against the barrel, when you switch it on, it moves nice and smoothly in and back out again. And it doesn't need cleaning, its clean as a whitsle, so my problem must lie somewhere else.... hmmm.... Should I remove the snorkel from the airbox? I also need to find out what the derestriced carb jet sizes are, if I need to change them. Cheers Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 17, 2011 Moderator Share Posted February 17, 2011 Thanks so far OG, now, is this the reed switch? I have also checked the powervalve movement, and when it is fully open, it sits flush against the barrel, when you switch it on, it moves nice and smoothly in and back out again. And it doesn't need cleaning, its clean as a whitsle, so my problem must lie somewhere else.... hmmm.... Should I remove the snorkel from the airbox? I also need to find out what the derestriced carb jet sizes are, if I need to change them. Cheers Yes thats it sam, just leave it removed from the speedo tucked out of the way somewhere...did you read the deristricting...topic? Sits flush against the barrel? I take you mean flush with the top of the exhaust port. Dont worry about jetting yet...one thing at a time. just do the reed switch for now. Link to comment Share on other sites More sharing options...
samslam2000uk Posted February 17, 2011 Author Share Posted February 17, 2011 Yes thats it sam, just leave it removed from the speedo tucked out of the way somewhere...did you read the deristricting...topic? Sits flush against the barrel? I take you mean flush with the top of the exhaust port. Dont worry about jetting yet...one thing at a time. just do the reed switch for now. Yeah sorry, I didn't mean to mislead! I meant the exhaust port! Well the reed switch is removed, tucked in behind the speedo casing. I should probably put my exhaust back on now lol. Feel free to be as technical as you need by the way, I may be a newbie poster on this forum but I'm quite a 2-stroke connoisseur! I usually post over at 125ccsportsbikes.com, and used to have a Cagiva Mito (which I pretty much rebuilt from scratch) but I thought I'd try over here, there isn't too much speciality on mx style bikes over there! Link to comment Share on other sites More sharing options...
samslam2000uk Posted February 17, 2011 Author Share Posted February 17, 2011 And I think most of the trouble I'm having may be because I'm losing a junk load of compression. Whoever last fiddled with my exhaust, never re-fitted it with an exhaust gasket. Penis. I'll buy an exhaust gasket, get that slapped on, and shout back the results Link to comment Share on other sites More sharing options...
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