hello all! im dave from northern ireland, im looking for any1 (male or female) that has knowledge of yamaha dt 125, in regards to tuning, i know some of u guys love 2 stroke bikes and would really appreciate some help on tuning my bike, regards....
dave

I had a DT 400 and an IT 400.What is the problem?? The first thing you do is change the spark plug. It can get oil fouled and if it looks good it still can be fouled up inside the plug.
The plug should be burning a light brown color on the end of it. Make sure the air cleaner is cleaned and oiled with filter oil before sticking it back in. You may have to turn the air screw in or out a quarter turn at a time to get it to have a good snappy throttle response and to make the plug burn right. If its been sitting a long time the gas may have gummed up the ports in the carburator also.

Dt 125 had a reed carb into the cases. Soak dirty fouled carb parts in a can of turpine solution. The reeds mechanism will need to be replaced. If the bike has been beat hard and continuously been wound out full throttle the piston and rings will need to be replaced. Simple compression test should determine that. Hope that helps some.

i can't speak to the dt specifically, but the **** lakeman and longhair are spewing sounds right; it's a freaking 2 stroke yammy; make it clean, if the springy parts are worn, replace them with stiffer parts; otherwise make certain it behaves as a combustion engine

what ailment do you see in this buggy?

<-- very happy with his pile of jap iron

Buy a manual. If you have any other questions once you've read it ask me.

yea the SHOP manual will help solve your little setrup problems. If it is more major you may have to get your fingers dirty...LOL

I had (now just remains) a couple early 70's DT250's and still have the shop manual. If you need any info out of it let me know. Or even any of the 'hard to find used parts'. I'm not sure what all is interchangable though, but, I don't see myself bringing them back to life any day soon.

thanks guys, im sending my engine to Stan Stevens of England to do a stage 3 tune, so that should release its full potential, hoping around 30 bhp, and still be reliable :)