Yamaha 125DT dies after higher revs?

[Guest]

I'm new to riding and my first bike is a Yamaha 125 DT (51 plate). Can't believe I hadn't started a long time the fun I'm having and I'm already looking to upgrade to something bigger.

However, when I've been riding in top gear with 7K+ revs for a little while, the power drops off and it just spluters along, sometimes to the point where it won't even idle. It will start up again a couple of seconds later though. Theres plenty of fuel in the bike and there no back firing, it just dies? The can make it tricking when overtaking knowing at some point the bike could start dieing. The bikes fine when riding at lower revs, it just when it's been sustained at higher revs for a little while.

I know this kind of stuff is hard diagnose but if anyone could suggest where to start looking I would be greatful.

[rennie]

hello and welcome to TMBF

say hello in the newbies section

It's a 2 stroke right?

could be almost anything!

first things I'd do is change the plug, maybe for a hotter rated one.

and make sure there was enough 2 stroke oil getting through.

[Guest]

Hi Rennie,

Yeah, it's a 2-stroke.

Thanks for the suggestions,

Guess what I'll be doing this weekend

[Anthony]

Could be too much fuel getting through, check the float heights as they might be wrong, as that could either starve or over feed the engine

[Guest]

whats the red line? look at rev counter, when the section goes red.

also check the oil bottle, could be low. (2stroke)

and coolant....

[Guest akey]

How long has it stood for, first job might be some fresh petrol as unleaded can go off after a few months.

[Guest]

Check your tank breather hole is not blocked, or if its got a pipe breather it's not kinked or trapped, this is quite a common but often overlooked cause of the symptoms you describe, a quick check to see if it is caused by the above is, next time the bike dies on you open the filler cap, then close it again to release the vacuum lock, if the bike runs OK immediately, there's your problem