BILL K Posted June 14, 2010 Share Posted June 14, 2010 I am trying to get this DT 175 running. It's been sitting for 15 years with gas in the carburetor. I got carb. cleaned (as far as I can tell)and got the bike running. The only problem is that it will only run with the choke on, it won't hold an idle and it loses power while trying to ride. It seems like the carb. is running lean but, i'm no mechanic and this is my first bout with a carburetor. If anyone has any suggestions, i would appericiate it. I have a CLYMER's book for this and I set the floats according to the book (along with some experimental adjustments) and I'm still having issues. Link to comment Share on other sites More sharing options...
turrican64 Posted June 14, 2010 Share Posted June 14, 2010 When you clean a carb out, make sure to use a good carb cleaner, dismantle the whole carb and soak all the little bits in the cleaner for at least a few hours. Go through all the jets and passages with a fine wire and an air compressor. As soon as that's done, set your air screw at 1 1/2 turns out, and the idle screw (should be able to turn it by hand) at 3-4 turns out for a start. Pop in a new B8ES plug and you should be off to the races. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 14, 2010 Moderator Share Posted June 14, 2010 Sounds like a possible blocked pilot jet, can you see daylight through it?. Other issues to consider with and old stroker are crank seals but sort the carb first. Link to comment Share on other sites More sharing options...
BILL K Posted June 14, 2010 Author Share Posted June 14, 2010 I can see light through the main jet. That was seized up when I started this whole this. Is the air screw and idle screw the same thing or are they two different adjustment screws? Link to comment Share on other sites More sharing options...
turrican64 Posted June 14, 2010 Share Posted June 14, 2010 I can see light through the main jet. That was seized up when I started this whole this. Is the air screw and idle screw the same thing or are they two different adjustment screws? They are different. The air screw is usually near the air filter side of the carb, and the idle adjust closer to the middle of the carb. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 14, 2010 Moderator Share Posted June 14, 2010 I asked if you could see light through the pilot jet not the main jet Link to comment Share on other sites More sharing options...
BILL K Posted June 14, 2010 Author Share Posted June 14, 2010 Where is the pilot jet located? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 14, 2010 Moderator Share Posted June 14, 2010 Where is the pilot jet located? Link to comment Share on other sites More sharing options...
turrican64 Posted June 15, 2010 Share Posted June 15, 2010 You're going to need a slotted screwdriver to get it out. That pilot would be the best thing to check. Link to comment Share on other sites More sharing options...
dpehrson Posted March 27, 2013 Share Posted March 27, 2013 dpehrson I had a similar problem with a 78 dt125 that I pulled from a scrap yard for $40. The engine would not idle after warm-up without the choke on. The problem... Apparantly someone before me placed a dab of thread locker on the air screw threads... I cleaned the carb about three times due to this problem, After a very careful and timely examination, I discovered that the airscrew was going very snug, which I had previously thought was seated, way to soon. I observed that the needle portion of the airscrew was not observed as even entering the air port orifice on the intake side of the carb. I examined the air screw threads of the carb and noticed debris gumming up the threads. I then continued to force thread past the thread locker and adventually to the real metal seat. At 01:00AM, I assembled and installed the carb and started her up. I warmed it up with the choke on and then pushed the choke in to discover that it purred like a kitten. One final adjustment to the air screw of 1/4 turn in and it idles clean without the choke and accelerates without hesitation. Who would have guessed... Link to comment Share on other sites More sharing options...
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