Hi everyone I'm new to this forum. I've come here in search of some much needed awnsers. I have a 78 dt 175 and it's driving me nuts! I've had the bike for about 6 months and I've gotten no where with it after a lot of work. So here's a sum up of what it does. The bike starts up very easy and make tremendous spark. The bike does idle but it's very rough and not right at all. I've cleaned the carburetor several times got new main and pilot jets and checked all holes to be clear and set the float height to factory settings which changed nothing. When I move the air mix screw it has no affect on how the bike runs at all all the way out and all the way in no change. Also when I give the bike any throttle at all It immediately tries to die it won't rev. I've tried moving the float height around which also changed nothing. I need some help here everyone any ideas will be appreciated

Closer but no cigar yet. I will move this to the workshop.

Its an air leak and on a Dt175 of that age the runaway favorite will be the crank seals.

I reckon the carb is the problem, maybe the passageways are blocked, spray through them with carb cleaner and blow them through with compressed air, try to prove they are clear by blowing air through them and seeing the result, you say you've cleaned the carb several times...to what degree I wonder?

how does the engine react to throttle with choke?

+1 I am with airhead if the mixture screw is having no effect then the passage is blocked,get yourself a gallon of TYME carb cleaner strip and soak the carb over night. When you are looking at the carb from the air filter side make sure you can blow air through the small holes

Thanks for the input guys. I have crank seals for it so I got to get them in then! I've soaked the carb completely twice and spread cleaner through it many times and blown it out with compressed air. The throttle reacts the same with the choke on it doesn't really change anything weather it's on or off. I'll check all the holes again specifically the ones on the air filter side agin though

Thanks again

The throttle reacts the same with the choke on it doesn't really change anything weather it's on or off.

The choke jet aint working either then,, remember the well [ in the bowl]where brass tube drops in, theres a small hole at bottom, it fills thru there,

Blackhat I'll take the carb apart and check that however the bike does react to the choke it won't start easy without the choke on when it's cold. Or run without it on until it warms up which makes sense