JoeWannaB

Hi Nick, I'm new to this forum and very new to restoring old bikes so this my not be helpful but I thought I should post up my experience in case it may help you. I have a DT 175A not the MX but I am having a similar experience to yours in regards to the bike not accelerating well in the mid to upper range. Mine idles beautifully and it will rev smoothly all the way to the redline without a hiccup while in neutral or with the clutch lever in. It usually runs pretty well up to about 4000-5000 rpms when under a load but after that, it bogs down. I adjusted the float level, checked the needle clip, set the timing, checked spark plug gap, completely cleaned out the gas tank, petcock and took the carb apart for a thourough cleaning. Each step of the way, I thought I had found the solution only to put it back together and have the exact same results. I was really banging my head against the wall. During my third time inside the carb, I managed to break the float and so I went to the internet in search of a replacement. While I was ordering the float, I decided to go ahead and order a new main jet, pilot jet, needle valve set and a few gaskets to perform a complete carb overhaul. As I was closely examining all the parts to determine if they needed replacement, I discovered that the O-ring that attaches to the bottom of the main nozzle was missing. It is my understanding that this O-ring makes a seal between the main Nozzle and the opening in the float bowl. If there isn't a seal, then gas can flow freely around the main nozzle. When the throttle is cracked wide open, a flood of gas is sucked into the mixture momentarily flooding the bike. At least that is my theory. I won't know for sure if this is what my problem is until my parts come in but it is the only "smoking gun" I have left. If this isn't helpful, I hope it is at least a good story. Good luck and let us know how you fix your problem. Joe

Hey all! Great forum. I had a DT 100 when I was a kid and now I've managed to acquire a '74 DT 175A so I'm sure I'll be spending plenty of time over in the classics section. Here's a pic of my project in it's current form. See you around. Joe