johnrgib Posted August 29, 2010 Share Posted August 29, 2010 Folks- I'm new to this forum but it looks as though my problem may not be. I have a 1980 Yamaha DT 125 Enduro. I'm the second owner and it has about 5,000 original miles - garage kept (always) and not run for over 10 years. It cranks fine, but the problem is that the engine struggles at mid to high end of the power band and it smokes a bit (at high end). The jets are relatively new, and the gas tank has been cleaned and sealed. Air filter is clean. Muffler is ok, for 30 years old and very difficuly to find a replacemtn for - unless others haev ideas?? Perhaps a larger question is, what type of carb do I actually have? The Clymers manual suggests that it is a Type III carb with an air screw to adjust air / fuel mixture. It would make sense that this would be something easy to try, but alas, there is no such screw on my carb. I doubt it's the wrong carb, but who knows. Any ideas for my power outage? sorry for the detail, but just giving the history. thanks Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 29, 2010 Moderator Share Posted August 29, 2010 5000 miles in 30 years That thing has got lazy! Welcome to the forum ...Paul Link to comment Share on other sites More sharing options...
DeTour Posted August 30, 2010 Share Posted August 30, 2010 Is the spark nice and strong? I had a similar problem where my bike ran fine at lower rpms, but once revved up it'd lose power fast. Turned out to be one winding on the primary coil had corosion. Took off that one wind around and problem solved. Also, take a picture of your carb and post it up, is it dirty at all? maybe the screw is just hidden or something.. Link to comment Share on other sites More sharing options...
burton500 Posted August 31, 2010 Share Posted August 31, 2010 If it's been stood for years, the left hand crank seal could probably do with replacing. Link to comment Share on other sites More sharing options...
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