Posted June 14, 201014 yr 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.
June 14, 201014 yr 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.
June 14, 201014 yr Moderator 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.
June 14, 201014 yr Author 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?
June 14, 201014 yr 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.
June 15, 201014 yr You're going to need a slotted screwdriver to get it out. That pilot would be the best thing to check.
March 27, 201311 yr 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...
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