Rudi

Choke up is ON and choke down is OFF, mixture screw should be 1 and a quarter turns out.

Yeh ive got a manual, dont worry now though ive done it, in the end i just got a pair of pliers and twisted the rubber around a little to break anything holding them on then they came off easily after that.

Thats what i was trying but the 2 coolant lines get in the way and i cant seem to get them off.

I know how to change a jet and where it is etc but on the DTR the carb is buried in the centre of the bike and surrounded by cables and pipes, ive had a go at getting the carb out i removed the rev counter cable and rearbrake resivior and a few other bits but i couldnt seem the get the 2 coolant pipes detached from the carb(the bike has been sitting for 5 years so things are abit harder to move). Anyone got some hints, tips or shortcuts to help me change the main jet. Anyone around the chingford (east london) area that wants to come have a shot at it, theres £20 in it for you if you're successful.

Thanks for the advice, ive got some new fibre reeds to be fitted and a full DEP pipe is already on so im pretty much sorted, just need to cut this piece of rubber off and upjet a little all the parts should be here tomorow or thursday then i can get on with it.

Yes i have several bigger jets on the way, im going to order a pre 2000 manifold and fit that(because they are made without the extra rubber piece) then remove the snorkel off the airbox then upjet to compensate for the increase in air flow, once all this is done and tested i will post my results and opinions for anyone who needs them in the future.

Maybe its still restricted, they have a reed switch in the speedo that stops the revs from incrasing once the speedo hits 60mph, a quick way to work out wether you still have this or not without taking apart your speedo is to read the revs that the bike usually tops out at then remove the speedo cable where it attaches to the speedo drive at the wheel, then take it out for a ride and see if it passes the rev it usually stops at(of course this time they should go higher because the speedo wont hit 60 because its not connected), once you have determined if you have got the restriction refer to this page http://www.dtr125.net/tuningf.htm for instructions on how to remove it along with other restrictors.

Been reading up on it, most say its a restrictor but some complained that they had lost a few mph off their top speed once they had cut it off, has anybody got a real picture of what the intake manifold actually looks like with the 'restrictor' still attached? All i have to go by is the amatuer drawing on dtr125.net, is it possible that this is to help the air-flow not restrict it OR maybe the people who removed it lost power because it was a restrictor but now their bike is running too lean and all they need to do is upjet the feel the benefits, can anyone help me to make the decision to cut it off or leave it be?

Stick a full DEP on it if you want better acceleration, ive got the 2002 DT125R with a DEP and it maxes out at a genuine 70mph (clocked on my GPS) but itll lift its self up in 1st and 2nd and with a bit of encouragement(dropping the clutch) 3rd aswell.