Hello there iv e got a 1998 dt125 and had to rebuild it from scratch anyway it starts up and runs for about 5 seconds and then bogs out, i have blown the jets out when i cleaned the carb shall i check the float in the car, and is there a idle screw on these Dt's many thanks :')
First off, Check for water in the fuel (evident by small globules), Float height on mine was betwen 15.5 and 16.5mm (currently at 16mm dead) Your air screw is the bigger one of the left of the carb, and your pilot/mixture screw is the small brass one about 1.5cm to the right
ive checked for water in the fuel, Clear pipes, i shall need to check the float aswell, my air screw has a twist part on it i think which i can adjust by turning left or right i can see the brass screw further down inside, im going try start it agian today and adjust the air screw when i get it running see if theres a diffrence, man thanks dufferz and plebpl
After a bit of raiding around, i found the "standard" settings for the screws... Air screw: Pre-99 its 1.5 turns out, 99-03 its 1.25 turns out. As a general rule i use the mixture/pilot screw at 1.5 turns out.. Also make sure to give that airfilter a good washing or replace it ;) .. Deffonately check that plug afterwards and see how it looks then
(My bike is currently doing the exact same, with a different problem every time)
Haha thanks for finding the standard settings for me thats a base of what i can work off now, So i tighten the screws just gently then 1.25- 1.50 turns out? yeah i will check the plug after matey, i would defently clean the air filter but my bike didnt have the air box from the man i bought it from so however i have an orginal dt125 air filter and just useing that stright onto the carb to protect debrey from gettin into the engine, when i purchase an air box do you think this would make a diffrence mate? my bike has dep exhaust thats it really im going to get it running sweet then completley powdercoat the frame spray the engine, tank, panels at work to orginal yamaha blue/purple =D has yours got any mods?
No problem dude. I think it would make a significant difference not having the standard airbox + filter setup, But im not sure so you cant quote me on that one, lol. Also yep, spot on for the screws..
I have no idea how much the dep pipe makes a difference to the fueling either.. but combined with the airbox situation i think it would be quite significant to it..
Still had no luck on mine yet either, keep having to wait for the damn o-ring on the carb to shrink every time i take it apart and change something..
No real mods on my bike though, Big-one silencer and the stock yammy downpipe with the rescrictor removed. Halfway through a sprayjob as well.. but then the engine went tits up, rebuilt and now its doing this instead..
Oh yeah, dont forget to check the position of the jet needle clip as well.
My problem: Starts with the choke on, revs to about 5000,6000rpm, then sounds like it floods and dies.. Managed to get it to run "properly" once, (it ticked over too!) Took it for a 10 mile ride (to its MOT - it passed) and it caned a full tank of fuel. Sat for 4 hours after, and wouldnt start again, with the same problem... Tempermental little cowbag that it is!
lol yes same im just waiting to purchase a air box, O ring mate? were is this o ring in the carb as im stripping my completly down tommorow, Big-one silencer there nice, yeas will definetly check the jet needle clip dude, ahh took it for its mot and passed then wouldnt start thats a gutter mate, my friend had a simular issue with his dt it drank the fuel like hell and and would run for short distances and then come to a stop and found out the choke was constantly staying on
O-ring that seals the bowl to the main carb body. When ya take it off it'll look like its far too big, and wont sit in its notch.. leave it out overnight in a warm dry place to let it shrink and you're good to go! Ya might not have to, but i did..
Will take the choke mechanism off mine today and have another look.. ANYTHING is a possibility now i think. Also gonna burn off all the carbon from inside the exhaust and see how much comes out.. Hopefully it'll sound better after that too :) I have also noticed a pinprick hole at the top of the downpipe that wont be helping anything..
my o-ring was allright didnt have too much trouble putting it back, yes definetly have a look at the choke mechanism its worth a try mate,
yeah should sound alot better with all that crappy hard carbon build out of the system,
at work i always have cars come in that arent worth much money and have small holes in there exhaust pipes i use "wurth" gum gum exhaust paste this stuff gose rock soild and lasts :D but im not sure how it will work out if you put it on a motorbike...
well i started up on my bike this morning trying to kick it over 20 kicks nothing was happening so i looked at the wiring joins and it looked abit shabby so i quickly stripped them back a bit and put new conectors on then 20 kicks later after i directly poured fuel into the carb it started and was idleing nice for about 8 seconds and then just bogged out and died on me went up to the parts shop and purchased a new plug aswell but no diffrence, then i was looking at my carb and the brass air screw was just completly butchered! the bugger that had the bike b4 me ruined it theres no head on it to adjust and its sat in there :(
I tried gum gum on the dep expany that come fitted to my bike, it was ok for a quick fix but didn't last long. To much pressure i think.
In regards to your fuel starvation, have you checked that fuel is flowing from the tank to the carb? The filters could be blocked at either end of the fuel line.
-- Edited by fused420 on Saturday 26th of November 2011 05:34:32 PM
yeah more than likely too much pressure, yes mate i have installed see threw carb pipes so i can see exactly whats happening, im hopeing when i purchase and air box it will fix the problem and i wont have to drill out the air screw,
You'd make the next owners life a lot easier if you were to do it anyway, and perhaps your own too *thumbs up*. Hopefully the airbox will fix things for you dude. Just found mine was leaking from the L/H crank seal, Still doesnt work though!
Try running it up with your fuel filler cap off. Some people on here have had trouble with their fillers caps not letting air in so causes an air lock in the system. Also when it cuts out check the fuel level in th float bowl. Crack off the drain screw at the bottom of the bowl with a length of clear tube bent into a U-shape attached to the drain nozzle. At least you'll know the bowl is full of fuel.
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Is that bits of piston ring firing out your tailpipe?
yeah im going to change just so it can be easier to diagnose future problems,i hope so too lol, ahh well atleast youve diagonoised were your problem is mate thats one less woryy,
Could you explain how to check the carb float in a little more detail that sounds intresting could posiibly be were im goin wrong cheers
You'll need some Vernier Calipers, When you open them there is a lil bit that comes out the bottom for measuring depths, stick that on the side of the carb furthest from the float pin, and measure the height to the top of the float without pressing down on the floats.. Google will probably give you a better explanation than i can btw.
It's also worthwhile checking both sides of the float as people can sometimes twist them when changing the height
Hey mate, I just got mine running nicely again! It turns out, the water-heating part of the carb had corroded internally and was letting water into my carb bowl.. Took all the guts out of my carb, borrowed a friends one, put all my internals in, and it ran/runs beautifully!
Had to change to needle clip to the middle as it was dying in the bottom end (under 4000rpm and it would flood and not pull away), but now its all sweet again.. at least.. for now..
Another way i thought of to test for this would be to attach one of the hoses coming from the head, to the other one leaving the carb out of the circuit
Its a possibility that this might have happened to yours.. ya never know mate, keep us updated!
thats great to hear dude, thats one less stress now you can get riding once agian,
those are the carb warmer pipes so isnt it posiible to loop the the hoses on the head and then loop the 2 hoses on the arb to preven air coming in threw the damged part of the carb, which needle clip is this matey?
yeah ill check mine too for that problem, its great to hear Dufferz :D
