Tone33 Posted August 8, 2009 Share Posted August 8, 2009 Hi, I am new to working on motorcycles so please bear with me. I picked up a 1980 DT175 for a couple hundred bucks last week and have been trying to get it running. I cleaned and refilled the gas tank, drained and refilled crankcase oil and 2 stroke engine oil, cleaned air filter box, took the carb off and, cleaned it out and reset the float height according to service manual (20mm+-2.5mm). I put everything back together and when i try to start it, it it'll sputter sometimes but never start. I do have spark (tested with in garage with light off), i have air since airbox is clean (no filter right now the old one rotted away), not sureif engine is getting fuel though. As you will see in the pictures below there is a brass nipple coming out of the bottom of the carb and not sure if it's supposed to have a hose on it going to somewhere. After trying to start it for a few minutes fuel starts to pour out from this nipple. Am I missing a hose or is this supposed to be open like this? Thanks, Tone Carb Pic 1 Carb Pic 2 Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 8, 2009 Moderator Share Posted August 8, 2009 Hi Tone (Tony?) the spigot you show is the overflow, put a pipe on it and run the open end down between the back of the engine and the swing arm pivot. Two things 1, sounds like your float needle valve is passing fuel as your carb is overflowing, the float height adjustment should be done with the little spring loaded pin uncompressed, if you did it this way then remove and inspect for a worn ring around the pointed tip of the valve. 2. do not run the bike without a filter as it will no doubt run very lean unless you jet to compensate, this will overheat the engine and may hole pistons or seize whilst being ridden, a start and the odd rev up not ridden will be ok until you fit the filter. ...Paul Link to comment Share on other sites More sharing options...
Tone33 Posted August 8, 2009 Author Share Posted August 8, 2009 To adjust the float I unscrewed the "cap" where the throttle cable goes into the top of the carb and removed the slider (with the pin) and the spring that keeps the slider pushed down. Then I took the bottom of the carb off to adjust the float by bending the tang... is that what you mean by "spring loaded pin uncompressed"? Assuming the answer to my question above is yes then i'll go ahead and check for the worn ring Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 8, 2009 Moderator Share Posted August 8, 2009 To adjust the float I unscrewed the "cap" where the throttle cable goes into the top of the carb and removed the slider (with the pin) and the spring that keeps the slider pushed down. Then I took the bottom of the carb off to adjust the float by bending the tang... is that what you mean by "spring loaded pin uncompressed"? Assuming the answer to my question above is yes then i'll go ahead and check for the worn ring The answer is no, all that about removing the throttle slide, needle and throttle sprin has no relevance to adjusting the float height...you just have to do all that to be able to remove the carb from the bike. The float needle valve has a spring loaded pin in the end of it. The correct float height is 21mm so 20mm as you quoted will give a high level anyhow...though not enough to overflow. Link to comment Share on other sites More sharing options...
Tone33 Posted August 8, 2009 Author Share Posted August 8, 2009 ok thanks. let me digest all this and see what i can figure out. i'll follow up and let you know what happens. Link to comment Share on other sites More sharing options...
little dave Posted September 1, 2009 Share Posted September 1, 2009 thanks for the link og. Link to comment Share on other sites More sharing options...
kiln Posted May 22, 2010 Share Posted May 22, 2010 Thank you very much for this extremely helpfull post.it saved me from buying a new carb. Link to comment Share on other sites More sharing options...
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