1986-87 DT40 running issues

[Solarman]

If steam, is it overheating? Is there a good pee stream at low & high speeds?

If smoking is due to fuel/ oil mixture, it may be normal? If excessive oil smoke, run the motor for a good hour (with some more fuel in tank), then check the plugs to see if black and oily/sooty - too rich, if so, you may need to open the mixture screw a little more (1/16 - 1/8th turn CCW).

Keep us posted.

[n1zmo86]

Here is a YouTube link to see it running with steam or smoke. Any ideas?

https://www.youtube.com/watch?v=tF78...uyy3OYPWCReO7w

Also it ran pretty good no issues with cutting out at all but was a bit funny on 3/4 throttle sometimes maybe just mixture? It just felt like it lost a bit of power intimitantly maybe a cylinder but it didnt really feel like that. I have a feeling I have an air leak on the fitting that screws into the tank. Not the fuel clip but it has like a plastic screw in plastic pick up that the fuel fitting screws into. I might replace tote tank. Cheers guys soo much help!
Aaron

[Solarman]

dt40, running issues

Aaron, video didn't help very much on telling if smoke, or steam. If the pee stream is not too hot, and exhaust is not too hot, then it is probably smoke from oil that is normal on 2 stroke motors. If water at exhaust is too hot to put hand in it, if it would scald/ burn to feel, it may be steam. That would mean not enough water cooling motor. But, I remember you mentioned replacing thermostat, if you used the proper one for your motor, I would think the temp is fine. It may be hot at exhaust, but probably not steam.
Sounds like it's time to put in the water for a proper test.
Good luck, let us know how it's going.

[frankmachine]

Hi all.. I have an '89 DT 40 which will run fine but suddenly at full throttle will die back to about half RPM's... stays there a while then if I pull back throttle and open her up again, away she goes.... ule filter and pump seem OK... Carb a bit harder to access... Are these motors supposed to have an air filter? Mine doesn't...........