Posted October 8, 200816 yr I have a 1980 Dt 125 that I bought a few weeks ago for a $100.00 that is in great shape and with a liitle carb clean runs great but getting it to run is a different story. It will not start by kicking it over I have to run it down the street a few times and dump the clutch for it to even try to run and when it does finally start it runs like crap I have to keep the throttle held wide open for it to stay running and it runs like it is choked if its warmed up but after driving it around for a few minutes like that it starts to run good but when I go to cold start it is nearly impossible to get it going. Any ideas on what might be wrong would be deeply appreciated thanks
October 8, 200816 yr Moderator I have a 1980 Dt 125 that I bought a few weeks ago for a $100.00 that is in great shape and with a liitle carb clean runs great but getting it to run is a different story. It will not start by kicking it over I have to run it down the street a few times and dump the clutch for it to even try to run and when it does finally start it runs like crap I have to keep the throttle held wide open for it to stay running and it runs like it is choked if its warmed up but after driving it around for a few minutes like that it starts to run good but when I go to cold start it is nearly impossible to get it going. Any ideas on what might be wrong would be deeply appreciated thanks You should strip the carb down again, sounds like two problems to me 1: Blocked pilot jet, hence the need to bump start it. 2: Fuel level too high in carb, (Runs like it is choked) Check the float height is set to the correct specification. 21mm
October 9, 200816 yr Author You should strip the carb down again, sounds like two problems to me 1: Blocked pilot jet, hence the need to bump start it. 2: Fuel level too high in carb, (Runs like it is choked) Check the float height is set to the correct specification. 21mm I actually think my bike has the wrong carb on it in my other post another guy told me it has a vm24ss on it but the one that is on there is a thirty something
October 9, 200816 yr Moderator I actually think my bike has the wrong carb on it in my other post another guy told me it has a vm24ss on it but the one that is on there is a thirty something Thats right they are the same carb with different jets, thirty something is way too big
October 9, 200816 yr Author Thats right they are the same carb with different jets, thirty something is way too big actually it says 3jc on the right side I thought it said 30 but where does it say the size on it
October 9, 200816 yr Moderator actually it says 3jc on the right side I thought it said 30 but where does it say the size on it The only similar number that i can find is a 3j000, There should be 5 digits on your carb too, can you look again, sometimes they are a bit hard to see 3J000 IS THE CARB FOR A DT125G, DT125H and is a VM22SS which is smaller than the 175
October 9, 200816 yr Moderator The only similar number that i can find is a 3j000, There should be 5 digits on your carb too, can you look again, sometimes they are a bit hard to see 3J000 IS THE CARB FOR A DT125G, DT125H and is a VM22SS which is smaller than the 175 You beat me to it OG, if your frame no is 3j0-000101 on, its a G, if its 3j0-000501 on, its a H. If you can put the frame number up we can check for certain, wonder why its a 22? bit odd all on its own when the umpteen other variants have 24.
October 14, 200816 yr Author The only similar number that i can find is a 3j000, There should be 5 digits on your carb too, can you look again, sometimes they are a bit hard to see 3J000 IS THE CARB FOR A DT125G, DT125H and is a VM22SS which is smaller than the 175 I also have a qustion about the electircal about when you turn the key if the headlight is suppose to turn on and are the turn signals suppose to work because all that works are the horn and tail light but when the bike is running everything works so I was just curious if that is how it is suppose to work
October 14, 200816 yr Moderator I also have a qustion about the electircal about when you turn the key if the headlight is suppose to turn on and are the turn signals suppose to work because all that works are the horn and tail light but when the bike is running everything works so I was just curious if that is how it is suppose to work The headlight only works when the engine is running because it runs from the magneto. You will notice a small pilot lamp in there, that will work without the engine running. Cant remember about indicators but i think that although they should work without the engine running...in reality there may not be enough uumph in the battery until you start the bike (its been a long time since ive had indicators on mine)
October 15, 200816 yr Author The headlight only works when the engine is running because it runs from the magneto. You will notice a small pilot lamp in there, that will work without the engine running. Cant remember about indicators but i think that although they should work without the engine running...in reality there may not be enough uumph in the battery until you start the bike (its been a long time since ive had indicators on mine) You cant adjust the timing on CDI can you?
October 16, 200816 yr Moderator You cant adjust the timing on CDI can you? Some you can and some you can't have a look at the stator plate mountings see if the holes are slotted.
October 16, 200816 yr Author Some you can and some you can't have a look at the stator plate mountings see if the holes are slotted. Is your 175 adjustable?
November 4, 200816 yr Author Ha... would low compression also make it hard to get going needing the pushing down the road?
November 4, 200816 yr Moderator would low compression also make it hard to get going needing the pushing down the road? Nope, i've got a 125 engine and the compression is so low you can turn it over by hand on the flywheel by hand WITHOUT removing the plug, and i'm not talking a struggle either. With the kick start its a struggle to find compresion to give it a good kick, but thats the thing it started easy as you like, hot ,cold,wet ,dry every time. When i pulled the motor for a look inside when i took the barrel off the rings FELL out, and i dont have feeler gagues thick enough to accurately measure the piston skirt clearance. Its easily well over a millimeter. Something that may make it a bit awquard to start is the crank seals, this is something OG told me, take off the generator cover and have a can of WD40 or similar handy. Get it running then spray the wd inside the generator if it runs better its the seal, check the gearbox breather in a glass of water, a constant stream bubbles will mean again that the seals are gone.
November 7, 200816 yr Author Nope, i've got a 125 engine and the compression is so low you can turn it over by hand on the flywheel by hand WITHOUT removing the plug, and i'm not talking a struggle either. With the kick start its a struggle to find compresion to give it a good kick, but thats the thing it started easy as you like, hot ,cold,wet ,dry every time. When i pulled the motor for a look inside when i took the barrel off the rings FELL out, and i dont have feeler gagues thick enough to accurately measure the piston skirt clearance. Its easily well over a millimeter. Something that may make it a bit awquard to start is the crank seals, this is something OG told me, take off the generator cover and have a can of WD40 or similar handy. Get it running then spray the wd inside the generator if it runs better its the seal, check the gearbox breather in a glass of water, a constant stream bubbles will mean again that the seals are gone. I have another question is a 1979 and a 1980 dt 125 pretty much the same and are there any differences in the engine at all?
November 7, 200816 yr Moderator For some reason the DT125 you lot were getting changed from points to CDI between 79-80 other than that they are the same.....
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