i need help! 1982 DT 125

[c_realica]

ok so i just got a 1982 dt 125

i've never owned a dirt bike before.

it starts fine. once i try to drive it i cant give it too much gas (almost none) or it will bog out and die unless i let the throttle out.

i thought it was old gas and oil so i changed that and cleaned the carb out and it still does the same thing.

i am out of ideas!

any help is appreciated.

thanks so much.

[Cynic]

ok so i just got a 1982 dt 125

i've never owned a dirt bike before.

it starts fine. once i try to drive it i cant give it too much gas (almost none) or it will bog out and die unless i let the throttle out.

i thought it was old gas and oil so i changed that and cleaned the carb out and it still does the same thing.

i am out of ideas!

any help is appreciated.

thanks so much.

What happens if you pull the choke as she starts to die out.

Is the plug good

Airfilter fitted and reasonably clean

Exhaust not too coked up.

My first suggestion would be the main jet blocked with a bit of rubbish or possibly float height. I'm assuming we are talking DT125MX not DT125LC. Although it doesent really matter all that much they are pretty similar.

[Airhead]

Could be a blocked main jet. as said by 'Cynic'

[c_realica]

ok im gonna try and put a new carb in. ill get back with results. thanks for imput.

what is the difference between the mx and lc?

[AndyDtr08]

ok im gonna try and put a new carb in. ill get back with results. thanks for imput.

what is the difference between the mx and lc?

Essentially, the MX stands for Moto X i believe, where as LC stands for Liquid Cooled. So either see if it has a radiatior, or see if the cylinder and head is smooth metal or has blades ( i dont know what the correct term is), but basically making more surface area for the cold air to make contact with to cool down the engine and prevent over heating. I think it will be a MK1 dt125LC, another way to determine this is to look at the swing arm. They were one of the last models to have a support strut going at a 45 ish degreee angle from the rear wheel, up to the frame under the seat.

You'll want to check that your throttle is set right as i know the later bikes have oil pumps that are made to account for poor set ups but im not too sure when these were implemented. If you have a haynes manual for the bike there is a "trouble shooting section" near the front that i've always found fairly useful. You look up the symptom and it will tell you things to check. Does sound like a mixture problem though, which as has been said already, could be the carb or a blocked air filter. Best of luck and let us know!

[Cynic]

Essentially, the MX stands for Moto X i believe, where as LC stands for Liquid Cooled. So either see if it has a radiatior, or see if the cylinder and head is smooth metal or has blades ( i dont know what the correct term is), but basically making more surface area for the cold air to make contact with to cool down the engine and prevent over heating. I think it will be a MK1 dt125LC, another way to determine this is to look at the swing arm. They were one of the last models to have a support strut going at a 45 ish degreee angle from the rear wheel, up to the frame under the seat.

Close Andy, the MK1 LC and the MX's share the same chassis and swing arm though, including the forks etc. The tank/seat and bodywork are different.

You really don't need to mess with a new carb, the VM carbs used on the DT's are pretty idiot resistant. An overhaul kit from motocarb (think thats what its called) will get you running lovely if there is a serious problem with the jets.

Strip out the carb again and run all the jets through with some fine copper wire, kettle flex stripped back is good. The copper doesent damage the brass but is man enough to shift what can be surprisingly stubbon particles of cr@p.

A particular favorite is the idle jet in my experience, although yours is running ok at idle so your ok there. The fact that it dies at a touch of throttle means the main jet needs looking at, and of course the needle height.

I may have missed a mention of it somewhere but you HAVE put a new plug in. 2strokes are incredibly ficke when it comes to the plugs.

[AndyDtr08]

Close Andy, the MK1 LC and the MX's share the same chassis and swing arm though, including the forks etc. The tank/seat and bodywork are different.

You really don't need to mess with a new carb, the VM carbs used on the DT's are pretty idiot resistant. An overhaul kit from motocarb (think thats what its called) will get you running lovely if there is a serious problem with the jets.

Strip out the carb again and run all the jets through with some fine copper wire, kettle flex stripped back is good. The copper doesent damage the brass but is man enough to shift what can be surprisingly stubbon particles of cr@p.

A particular favorite is the idle jet in my experience, although yours is running ok at idle so your ok there. The fact that it dies at a touch of throttle means the main jet needs looking at, and of course the needle height.

I may have missed a mention of it somewhere but you HAVE put a new plug in. 2strokes are incredibly ficke when it comes to the plugs.

Ah, i see! And thats why i want to interview you for the documentary and not myself! I wont hijack this thread with that though. I tried pming you about it but it said you couldnt recieve emails, presumably because your inbox is full (mr popular!). Ill try again this eve!

Yeah, as cynic said. Its not worth bothering with a new carb unless you have money to throw around and little time. I've had my dtre carb off and apart when mine had some similar issues and it cleaned up a treat, went back on with the same gaskets and sorted it, even though i didnt see anything that could have caused the boggin issue in the first place, may have just shifted from turning the carb at an angle that it never see's when fixed in place on the bike.

I think i also changed the plug at the same time, you could check the gap and with that out you'll be able to see if the running problems are caused by a bad mixture. There are many photo comparisons online and in the haynes manual that cna help with that. I'd find one now but i keep having to tell myself for coming back on here every 2 minutes when i should be video editing!!!!!

[c_realica]

you guys have been so much help!

i took the carb out and cleaned it up. it runs 100 times better!!!

on another note, does the oil light only turn on because of the oil pressure?

[Airhead]

you guys have been so much help!

i took the carb out and cleaned it up. it runs 100 times better!!!

on another note, does the oil light only turn on because of the oil pressure?

The oil light is there just to let you know the LEVEL is getting low in the tank. it has nothing to do with pressure.

1: It will be on if you are riding and the level becomes low, if it does dont panic but top up with 2 stroke oil at the first opportunity, stick to the same brand.

2: It will also be on when the ignition is on and the bike is in neutral, even with lots of oil in the tank. This is a bulb check facility and you should check that this is so when you ride the bike.

...Paul

[AndyDtr08]

The oil light is there just to let you know the LEVEL is getting low in the tank. it has nothing to do with pressure.

1: It will be on if you are riding and the level becomes low, if it does dont panic but top up with 2 stroke oil at the first opportunity, stick to the same brand.

2: It will also be on when the ignition is on and the bike is in neutral, even with lots of oil in the tank. This is a bulb check facility and you should check that this is so when you ride the bike.

...Paul

And the same type of oil. You now get synthetic as well as the standard. I've always used synthetic on my dtre as thats what was in it when i bought the bike. I use Castrol for the older offroad bikes. I was told to try and avoid switching between the 2.