hi need some help!!! my yamaha dt 125x has been giving me loads of grief lately basically it wont run write when i fire her up she runs fine on choke but when i take the choke off it runs down the revs and cuts out the same way as if i ran out of petrol but its tempermental i tried turning the tickover up that helped then when i take it out on the road as soon as i give it over half throttle it tries cutting out so i either have to keep to 40 or ride the choke!! also the other day i went out it seemed ok so i gave it some throttle to see howw ok it was got to 70 then it just lost all power. i dont have loads of money so i dont want to take to a garage n they say itl cost 300 to fix. please help any ideas????????

id say youv got an air leak somewhere have a look for splits in your manifold and check the airfilter and box is in good condition and fitted correctly

hi need some help!!! my yamaha dt 125x has been giving me loads of grief lately basically it wont run write when i fire her up she runs fine on choke but when i take the choke off it runs down the revs and cuts out the same way as if i ran out of petrol but its tempermental i tried turning the tickover up that helped then when i take it out on the road as soon as i give it over half throttle it tries cutting out so i either have to keep to 40 or ride the choke!! also the other day i went out it seemed ok so i gave it some throttle to see howw ok it was got to 70 then it just lost all power. i dont have loads of money so i dont want to take to a garage n they say itl cost 300 to fix. please help any ideas????????

Check you have a good flow rate of petrol to the carb. If you do then i'm afraid it sounds like a carb strip and clean, may be a blocked pilot jet. Thats all I know as I havent done it yet on mine.

Check you have a good flow rate of petrol to the carb. If you do then i'm afraid it sounds like a carb strip and clean, may be a blocked pilot jet. Thats all I know as I havent done it yet on mine.

Check you have a good flow rate of petrol to the carb. If you do then i'm afraid it sounds like a carb strip and clean, may be a blocked pilot jet. Thats all I know as I havent done it yet on mine.

just want to say ur dt 175 looks like new. nice bike!

could this be caused by incorrect air/fuel mix ? the problem being that who i bought the bike off has destroyed the air fuel mix screw and i cant see the easiest way of getting this out?????

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could this be caused by incorrect air/fuel mix ? the problem being that who i bought the bike off has destroyed the air fuel mix screw and i cant see the easiest way of getting this out?????

/

Not sure but water in the float bowl can do that. drain it and try again.

Has the bike ever run correctly with the mixture screw as it is?

Have you been feeding it cheap supermarket fuel?

I've had to scrap a carb before now when the mixture screw got mangled, as it caused similar issues. There is every chance thats thats the cause as the choke changes the mixture.

There are other things that can cause the issue like the blocked power jet, worn main jet or pilot jet etc. You will have to strip the carb to find these though. 

Personally I would replace the carb, it will save you a whole lot of headaches in the long run.

Vez

not sure wot model dt125 u have? but if its the same as the 200s then it shouldnt have a mixture screw.

not sure wot model dt125 u have? but if its the same as the 200s then it shouldnt have a mixture screw.

From the first post i believe he has a DT125X which is the SM version of the late DTR's. It's not the same as the DT200, as the DTR/DTRE/DTX 125's mikuni carb has a mixture screw.

Vez.

thanks for your replies. im gona take the carb of check n clean it iv a feellin it might hav a blockage. my bike hasent always run like this and i definetly dont use supermarket oil. il let u know what i find.