20 Most Recent 2001 Yamaha DT 125 R - Page 4 Questions & Answers

Check the attached links, "I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info." Yamaha XT125 Carb Tips Mikuni 3D6 Mikuni Carb Series 3 assembly video with details Mikuni ucal carburetor pipes diagrams DT 125 Yamaha Google Search mikuni carb diagram Google Search

through experience i can tell you that dt125 r's are prone to warping heads and even barrels can distort at the studs.get the head and barrel back off and get them checked or skimmed minimally to be on the safe side,i would also leave the thermostat out.

All the Japanese bikes I have owned won't start in gear unless you pull in the clutch lever. There is a small plunger switch fixed to the clutch lever stock (the part that does not move). This switch is connected to the ignition and starter circuits, so when the clutch lever is closed the starter won't turn. Check the bike starts OK when not in gear. If you try to start the bike in gear and it does not start with the clutch lever pulled then the switch is not working. Hope this helps.

http://www.dt125.cz/download/Owners_Manual-DT125R.pdf Please rate me if this helped you, thanks.

Search web for "De Restricting my DT125R" there are several sites. Caution when doing this as over revving the motor can have disastrous results. An use only the best lubes and high octane fuels. I De Restricted my 1981 YZ125 an she still Runs today.

check for spark to the spark plug if it works, check the carburetor is not a dirty jet.

dirt in the carb , strip and clean ! clean tank also ! low compression , 100psi or more on tester and if less then remove cylinder head and check bore for wear or damage , gasket also ! if damage in bore then a rebore and oversize piston kit and new gaskets etc !

i do not think so this sounds like a motor seizure you will need to take the spark plug out and see if the piston top is alright if it is try to turn over with the plug out if it want turn over then it has siezed up and will need to be rebuilt

must be a faulty tachometer because that bike at 12000 rpm would sound like its about to explode.

Carb no doubt needs a rebuild. Dirt, debris, is not allowing fuel in. Check fuel lines as well. No need to do a part job. Carb ports easily get clogged

Does the bike leak oil, if so fix the leak as 2-stroke engine's fuel supply run through engine casing. Check exhaust for blockages. Bike is running lean/rich

Change needle and seat

I would make sure the oil level is not too high. Next I would remove a spark plug and test compression to see whether your rings are worn excessively.Hope this helps.