Yamaha DT 125 problem

[dirtydt]

I own a yamaha dt 125 2003 the model with the 2 stroke oil pump, basically my bike is running okay but it doesn't go as fast as it should the power band is not as pokey as it was before, however when i go for a day of off roading and revving the bike really hard and generally getting fairly hot the bike absolutely flys for a week or so and then starts to go slower again! What is wrong with it? My thought is that the 2 stroke pump is running a bit too rich causing the power valve to not open properly and then after riding off road and really revving the bike and it getting fairly hot for a good few hours it burns off all the built up 2 stroke? What is your opinion? also when i was off roading yesterday my bike really spluttered at about 7-8000 revs (power band) and wouldnt rev any higher, it did this for 10 minutes or so and then began to run fine again

[Pete.]

Sounds like the exhaust is full of carbon.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[dirtydt]

[Suntan Sid]

[Pete.]

Yep, I've seen a bike that wouldn't rev at all from being clogged up. remove the exhaust pipe and take a look inside the pipe and inside the exhaust port.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[dirtydt]

[Suntan Sid]

Usually involves some rubber gloves and caustic soda!

Google "Decoke two stroke exhaust".
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"Everybody needs money, that's why they call it money!"