Leftyno1 Posted November 2, 2015 Share Posted November 2, 2015 Hi all Have noticed that while messing about with my Mikuni TM 28 carb that bike revs so much better with snorkel out, but as average temp here is about 78, have to be carefull about overheating due to extra air flow, what has anybody else found with the snorkel as in or out being better. also i must have been lucky with my previous 2 strokes which i never touched Carburetor wise ( this is the rant bit ) as i have had the mikuni in and out more times then the Pope has said Amen, i have researched so much info on carb but there seems to be no definitive setup mine is not happy with a 240 or 230 Jet 220 jet for my carb runs best but still working on idle which is crap and mid range . but on the plus side i can remove and fit the carb in approx 15 to 20 mins lol. So what i need is either to pay Stan Stephens to come over and tune it ( If I was wealthy,I would bloody do it ) or some kind soul on here has info that would assist in my quest to ride the bike more than i work on it , Cheers all Link to comment Share on other sites More sharing options...
blackhat250 Posted November 3, 2015 Share Posted November 3, 2015 Crap mid range " well that's needle jet / needle height , your idle ? whats happening ,, more info ,, Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 3, 2015 Moderator Share Posted November 3, 2015 when I had mine I put a bigger snorkel on it, the best of both worlds,,,able to suck more air but none of that horrid induction noise Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Hi well have refitted 220 Jet and found that idle screw was missing the steel washer ,well that changed everything ( after fitting one ) idles far better and low and mid range so much betterbut bike still not going past 7000 rpm when riding is that exhaust or power valve, I realize that bike is a 125 cc so not ever going to be like my RD 350 LC , but it is a very small power band and would like to make riding it easyer on the gear changes, any clues to where I should look. Link to comment Share on other sites More sharing options...
finnerz89 Posted November 4, 2015 Share Posted November 4, 2015 7k rpm is when the Rev limiter kicks in on newer DT's, what year is yours? Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Mine is a 2002 model Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 4, 2015 Moderator Share Posted November 4, 2015 is your power valve set in a restricted position, did you ever check it opens fully? Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Going to check it next as it does not make a sound when key is turned before start up, I take it there are instructions how to set it properly on here, must admit it's fun tinkering with a bike again takes me back to the days when I tried to get 50 DX in Kenny Roberts colours to go faster (best after a thunder storm when air is oxygen rich lol .) Thanks Link to comment Share on other sites More sharing options...
finnerz89 Posted November 4, 2015 Share Posted November 4, 2015 Yeah there's a couple of pinned threads on here regarding setup. First get it operating, sounds like the cables might be misadjusted or disconnected, then see about the rev limiter Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Well took cover off power Valve and turned key on ignition nothing happened revved bike upto 9000 rpm and still no movement this is how it looked whole time ,so I guess this is not correct lol, so how do i get to the pinned articles so I can carry on in my quest for world domination on my DT 125 R, bloody hell this coffee is strong, cheers. Link to comment Share on other sites More sharing options...
blackhat250 Posted November 4, 2015 Share Posted November 4, 2015 (edited) Go to workshop ",section, pinned threads are have a green PIN, beside them , your p/valve needs cleaning, Edited November 4, 2015 by blackhat250 Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 4, 2015 Moderator Share Posted November 4, 2015 (edited) when you turn on the ignition key the pv should do a couple of cleaning sweeps, you should hear the servo motor noise 'zzzt zzzt' as it does this...then after the cleaning that U shaped cutout should be in perfect alignment with the blind hole you can see at the top. you should investigate whether the pv has become seized in its current position maybe...is the pv servo electrics plugged in? this one isn't pinned any longer Edited November 4, 2015 by Airhead Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Took plastic section off and metal key ? turned easily so refitted plastic pulley and bolt, will investigate further tomorrow thanks for advice will let you know how it goes tomorrow ,going to look at those pinned threads,cheers again. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 4, 2015 Moderator Share Posted November 4, 2015 I just linked one!...not pinned any longer Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 4, 2015 Author Share Posted November 4, 2015 Thanks Airhead making a coffee and getting ready to read the Link, Thanks Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 5, 2015 Author Share Posted November 5, 2015 Well all wires connected up to powervalve checked fuses OK ,pulley wires connected but nothing happening when turning Key, any clues anyone I hate electrical problems ( growling noise ). Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 5, 2015 Moderator Share Posted November 5, 2015 I dunno fella, the pv is operated fro a little servo motor under the tank somewhere, did you say the pv is not stiff to rotate in any way? Link to comment Share on other sites More sharing options...
finnerz89 Posted November 5, 2015 Share Posted November 5, 2015 Hmmm servo might be duff then. If someone's had the PV pinned open at some point it may have damaged the servo Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 5, 2015 Author Share Posted November 5, 2015 Hi Yes power valve turns when plastic pulley is removed very easily actually, took tank off and checked connections at servo took cover off it to expose pulley wires ( not to tight ) but pulley will not rotate at servo but I think this is because it is electrically driven so could not be manualy opened, so I am thinking the servo is Kaput, bike can be ridden just needs revving alot. Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 5, 2015 Author Share Posted November 5, 2015 WOW 336 GBP for a servo for that i want it transforming into a RD500LC LOL , think i have found one on Ebay for 85 pounds second hand, seeing as i have in my short time of owning bike never had a operating servo do they make a differance to the ride quality on bike if not operational ? Link to comment Share on other sites More sharing options...
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