DT125R ARCHIVE

Spartan · DTR Senior Member

Air screw problem

plebpl · Guru

try heating it up, it will expand the carb so u might be able to get it out. (make sure all the petrol is out ; )

Dickhead · Nonce

try ive probs got a spair screw if u want to drill it out or somthing

-- Edited by robin on Sunday 6th of June 2010 01:33:44 AM

RudiRulez · DTR Senior Member

plenty of WD40 thats what got mine moving.

Spartan · DTR Senior Member

Right, tried loads of wd40 and some heating but still no luck. It got to the stage where the head of the screw had crumbled away and no flat head screwdriver could turn it.

It's now been drilled out, i went slightly off angle and into the side of the screw hole widening it abit but this shouldn't matter i'm thinking as the rubber o-ring will still seal it up at the bottom - as long as the screw doesn't wobble about now disbelief

I think it was the spring that was causing it to jam it the end. I was at my local yammy shop yesterday and ordered a new air screw - £10 ffs!

Robin, are the air screws the same for dt's and dtr's? I worked out my carb is a flat side i think.

-- Edited by Spartan on Sunday 6th of June 2010 02:01:30 PM

Dickhead · Nonce

i have never seen a dt with a round slide in my life apart frpm the air cooled ones

Spartan · DTR Senior Member

Can any harm be done by riding without an air screw , not saying i'm going to though. Apart from the mixture been off will the bike even run??

craigbulmer · Guru

Might be dodgy lol. Run very lean.

What are the perfect settings for the air screw? Im a complete n00b with carbs and i wanna have a fiddle as its crap in top end.

Malc · DTR Senior Member

Craig,

Pre-99 its 1.5 turns out, 99-03 its 1.25 turns out, and 04 onwards its 0.25 turns out. Wind it in fully until it lightly seats (hardly any pressure) then wind it out accordingly.

Malc · DTR Senior Member

Spartan,

It'll screw up your jetting entirely with no airscrew in there at all, and you greatly increase the risk of seizure. In a word - don't!

craigbulmer · Guru

Okay cheers, il give it a go ;)

Spartan · DTR Senior Member

Cool good to know cheers malc. Yeah thanks for info about the setup too, will make things easier for when i get the new one, just waiting on yammy dealer now.

With the setup of the idle screw I was just going to adjust it by ear, i don't have a rev meter but that should be ok shouldn't it?

Malc · DTR Senior Member

Yeah, just wtf Yamaha were thinking when they left the tacho off the DTRE/X I'll never work out...

When's the engine's nicely warmed up, just adjust it til it ticks over smoothly without racing.

Spartan wrote:
Cool good to know cheers malc. Yeah thanks for info about the setup too, will make things easier for when i get the new one, just waiting on yammy dealer now.

With the setup of the idle screw I was just going to adjust it by ear, i don't have a rev meter but that should be ok shouldn't it?

Spartan · DTR Senior Member

Nice one will do just that. Yeah it doesn't really bother me that much now, can one be added?

Malc · DTR Senior Member

Yeah, I've done it myself, can be a ballache getting parts cheap, engine internals I had to buy at Yamahahaha spares prices, but its not difficult as the engine casings are almost pre-RE/X anyway.

Spartan · DTR Senior Member

Cool that sounds promising. How would i go about doing it malc, what parts would be needed?

Cheers

Spartan · DTR Senior Member

Well got the new air screw today and put it in but guess what i gotta a problem now cry

For the past hour i have been trying it at different settings but no matter what whenever i apply the throttle the response is very slow, if i quickly open it up fully it just dies.

I think this is right - turning the screw left makes it leaner and right makes it richer?

I put the screw in all way until it seated and then turned it .25 of a turn to the left. Have tried turning it more in small steps but i can't get the throttle to respond fast enough.

I have tried adjusting the idle screw too - the bike idles at a good speed but as soon as i give it the beans there is nothing there???

I'm abit confused, fekking air screw. What do you think?

Thanks a lot.

plebpl · Guru

sounds stupid but, is the bike warmed up? and if yes check jet and make sure the car is not clogged anywhere.

Malc · DTR Senior Member

Any chance you got an airleak? Alternatively, a kinked fuel pipe?

Spartan · DTR Senior Member

Thanks for replies guys. Yep i warmed the bike up first, in fact i forgot to mention that it started to overheat after about 5min so much so that the coolant expansion bottle started to bubble like a kettle. Had to switch the bike off cause it was too hot.

What would cause it to overheat so quickly?

Over the weekend I had the carb out to clean, also had to drill the air screw out, only thing i couldn't do was remove the floats to check the jetting, the pin would not come out and tbh i did not have the correct tool to remove it (needle nosed pliers). Oh and I made sure to bleed the oil pump too as the oil delivery pipes were disconnected.

Hmm...I know the fuel pipe is not kinked because i made sure of that when i put the carb back in.

This is abit strange.

DeeTee · DTR Senior Member

Not read the thread but it sounds like your head gasket has gone thats why your expansion tank bubbles

-- Edited by DeeTee on Thursday 10th of June 2010 08:57:25 PM

Spartan · DTR Senior Member

Sorry for ignorance DeeTee that is the main gasket which sits between the cylinder block and head?

Just thinking when i connected the two pipes back to the carb coming off the cylinder block - sitting on the bike i connected the oil pipe to the left upper pipe on carb and the other to the right lower pipe on carb, think it's a warmer/breather pipe. Does that make sense?

If these pipes are connected incorrectly could that cause problems?

DeeTee · DTR Senior Member

This is how the pipes connect to the cylinder head, but the bubbling is a classic tell tale of a head gasket fault

craigbulmer · Guru

I just jizzed over that picture of your engine. Its so clean, and neat and perfect and not a reflection of mine!

Spartan · DTR Senior Member

lol craig.

Nice engine man biggrin

cheers for the pics, i can't get to my bike now but i will check tomorrow. I think i've got it setup right.

I'm not sure how the head gasket might have blown though, the bike hasn't been out my garage for almost a month now disbelief

, the only thing i have done is take the carb out and replace the air screw.

The last time i went out on it there were no signs of any faults, no overheating. If i didn't replace the screw it would have been on me mind, things like that get to me if they aint right haha.

-- Edited by Spartan on Thursday 10th of June 2010 10:29:29 PM

Spartan · DTR Senior Member

Hey guys, fixed it.

After speaking to a mate at work today it turned out to be the needle, I took it out the carb and you know the 3 knotches at the top, the little circlip was at the bottom so was allowing more petrol in than needed - it was being flooded which is why it was dying. I put it back to the middle knotch and it works fine now, the airscrew actually works now too so i can tweak it. Throttle is responsive again, just got back from a ride.

The overheating has stopped, apparently as the bike was stationary there was no airflow through the radiator to cool it down as i was revving it.

So there you go, cool eh.