Hello everyone I'm Liam i have had my Yamaha DT 125 R T reg for around two weeks and until two days ago it was running smoothly with no issues then while going to work it suddenly coughed and the engine died.

It will start up now and then but when i go to the higher (5-6 thousand) revs it cuts out again.

its three quarters full of fresh fuel

checked my spark plug and its clean.

checked fuel line and seems to flow well

Indicators etc work when ignition turned on

Apologies in advance if this is badly explained i have very little mechanical experience.

Thank you.

2stroke ownership rule number one, lesson one, try another plug.

Lesson 2 repeat lesson one with another plug.

Not kidding, lots of 2 stroke ills come from bad plugs and in the case of yammy powervalve motors the battery as well, as the signals can get messy and make it do some daft stuff.

Then lesson 3 clean the carb internally.

There you go 2 stroke ills in a jiffy

Does it have an inline fuel filter? A filter between the tank and the carb or is it just a rubber pipe?

I would take off the carb. Strip it, clean all of the jets and check the float height. I would also take off the fuel petcock (fuel tap) and strip and clean this too.

Thank you Cynic Ill grab a new plug tomorrow and try that.

No it doesn't have a filter just a pipe and ok if the new plugs don't help ill strip down and clean it all out thank you both for the advice. Liam

No problem. I have had 2 problems on my tdr that were both down to plugs. Looked ok and sparked but once in the cyl. Nothing.

I understand that the crappy nature of a 2stroke charge makes the plugs a lot more critical than a 4stroke. It is also an easy one to try. Esp on a dt.

Not so on thr TDR it will cost skin on that. I know.

Hi Cynic took your advice and swapped the plug and it started first time and runs beautifully thanks for the advice. Liam

Glad you sorted it, any 2 stroke owner with any experience will have a few good plugs to hand to check with at the first sign of trouble.

It would be worthwhile to get another plug and swap on to that and then keep this one, then if you have issues again its a good check. Its not uncommon to have duff plugs straight out the box. Don't trust it just cos its new MAKE SURE.

Ok ill grab a couple more good ones and check they work well an keep them to hand thanks again.for your help.