DT125R ARCHIVE

fused420 · DTR Senior Member

Running Rich

NORFE · DTR Trusted Engine Builder

put the needle to std settings, check rest of settings to manual spec,the bike will be more than run in now lol after that milage dont n o why people think they have to do 500 miles lol

i had ported top end, ful dep,modded airbox and never had to touch the jetting and it ran spot on... have u checked ur oil pump settings make sure its not over lubin...

Calum122 · Guru

NORFE wrote:
put the needle to std settings, check rest of settings to manual spec,the bike will be more than run in now lol after that milage dont n o why people think they have to do 500 miles lol
i had ported top end, ful dep,modded airbox and never had to touch the jetting and it ran spot on... have u checked ur oil pump settings make sure its not over lubin...

Its what it says in my Polini hand book. Well they said 300 miles actually. Better safe than sorry.

fused420 · DTR Senior Member

As Cal says, better safe then sorry really, but also after rebuilding the whole bike, and going from 240 (230 220) main jet down to 210 just to get her ridable, I couldn't be assed to keep experimenting.
Done the starting from standard settings thing too, and that has left me where I am today, 210 on leanest needle setting, with holes all over the air box. Low and mid range power are not so bad, its the top end that is weakest.
Oil pump seems to be fine.
I thought about ordering a 200 main jet, but as 210 is the smallest these bikes came out of the factory with, it seemed like I would just be masking a problem rather then solving one.

fused420 · DTR Senior Member

Anyone?

NORFE · DTR Trusted Engine Builder

if in doubt id always start from std, std jets, airbox, carb settings, auto lube...if its still out then start looking elswhere...

also check the float height

http://www.thumpertalk.com/topic/347305-is-your-two-stroke-running-rich-read-here/

Calum122 · Guru

240 standard. Get everything back to standard. Something isn't right.

fused420 · DTR Senior Member

Thanks Norfe I have read that before, but good refresher before I have a play about with things tomorrow

fused420 · DTR Senior Member

My carb came from a 04 RE that had 210 standard. With a 240 in the bike was way to rich

fused420 · DTR Senior Member

No, you think they could be the problem? They should be ok, but I suppose its worth a look

Edit: @Stillbroke

-- Edited by fused420 on Monday 29th of April 2013 12:40:24 PM

fused420 · DTR Senior Member

It's looking that way.

There shouldn't be any obstructions, but I will double check.

No bottle on boot.

The reeds will be checked. Boost bottle is fine.

New plug.

Expansion chamber is fine, same problem when I had the Dep fitted.

If I can be arsed after my dinner, I will go out and check the reeds, and try the other air filter. Otherwise tomorrow, as its not looking like im goingt to make London..

Thanks

-- Edited by fused420 on Monday 29th of April 2013 04:26:04 PM

fused420 · DTR Senior Member

I pulled the carb apart yesterday and found one of the floats slightly bent out of position, the bit of plastic that covers the jets missing, and I also found the choke mechanism to be a bit sticky so it wasn't closing off fully. So I reset the floats, replaced the missing piece of plastic, and cleaned up the choke plunger. I then put everything back to standard settings, snorkel back in the lot, and went for a test ride and...you guessed it...still RICH!
First half of the throttle is nice and responsive, then at about 7k rpm the engine cuts out, and off the throttle the engine kind of sounds like it is repeating on its self.
I have to go to the post office in a bit so im going to remove the air filter door, my guess is it will run much better..

Anyone got any input? I'm meant to be riding to London tomorrow :/

stillbroke · Guru

have you checked the reeds?

Calum122 · Guru

Alright mate. Are the carb warmer pipes connected.

I have a dtre and i find this mate.

From cold. No matter how long you wait for it to warm up. The bike will splutter at about 6K rpm. It will bellow smoke and splutter and refuse to go past 6k.

Once its been ran for about 5 mins on the move. Suddenly you'll get full power.

So just try that mate. I know it sounds weird but I guess it is.

Sort of like a anti rag from cold feature lol. Just ride the bike softly up the road a few times. Then open the throttle up and see what happens.

fused420 · DTR Senior Member

@Callum carb pipes are connected. And I always warm the bike up before I try and open her up.

Calum122 · Guru

Cool.

Is it always spluttering all the time. Or is it only until the engine reaches optimum temperature?

Otherwise thats normal for the dtre carb.

fused420 · DTR Senior Member

All the time.

I just went to the post office with the air filter door off and she flew, bottom end wasn't as responsive but 6k+ was rapid! Knowing that the lower rev range SHOULD be easy enough to tune in, its tempting to just cut the top of the air box off like some of the lads on here have done, and then tune it in from there. But I would rather get it running how it should, and not have to worry about what ever problem i'd be masking coming back and biting me on the ass in the future.

The only other thing I can think to do is dig the old air filter out of the shed, give it a clean, and give that a go, maybe the pattern one I got from ebay is more restrictive then the original.

Calum122 · Guru

Ok so it's lack of air.

So why do you have a lack of air?

Is there anything stuck in the carb boot?

Does the carb boot have a bottle on the side?

That will want to come off and be bunged up if it has. That's a restriction that restricts air flow.

Is the carb free from obstructions.

Are the reed petals old and need replacing. Is the boost bottle installed correctly.

Is the spark plug old and need replacing.

Is the expansion chamber clogged up? Does it need decoking.

fused420 · DTR Senior Member

Reeds are fine, and the old air filter made no difference what so ever.

One thing that I forgot to mention is it bogs first quarter throttle unless the air screw is off, to half a turn out. Air box open or not.

With the air box sealed up as standard it runs great up to 6-7k then cuts out. With the air box open it runs ok up to 6-7k then flies.

The only thing I can think is to pull the carb apart again and have a look at the pilot circuit and jets. In fact I think I have a spare pilot jet in the shed, so im going to head round the dealership and get a brand new 210 and swap both of the jets altogether and see if that makes any difference..

fused420 · DTR Senior Member

Nope still Schit.

Anyone got any ideas? I'm all out :(

On the plus side I did just win these though!:
http://www.ebay.co.uk/itm/251267473815?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Recon they will be any good? Or anyone else got them?

-- Edited by fused420 on Wednesday 1st of May 2013 02:40:04 PM

NEV · Guru

If at desperate measures mate, take it to a local bike garage, let them tell you and quote for job, it may be reasonable price, and you can pay them, but if not, and sounds costly, at least you know what it is, and maybe carry out maintenance/repair yourself?

fused420 · DTR Senior Member

I might have to give that a go, thanks Nev

Do you think them reeds I won will be much good?

NEV · Guru

You can give it a go aye, just make sure the 6 small holding screws have Loctite on them, you don't want them coming loose, and maybe renew jubilee clips and gaskets while your at it. You need an airtight seal, for when everything is all put back together.

fused420 · DTR Senior Member

Thanks mate I will do. I have ordered a 200 main jet as well, just to see if it makes much difference.

So to sum things up for the moment, first 1/4 throttle is lean, hence needing air screw closed, and 3/4 to full throttle is rich, hence needing to open the air box door. All of this despite being on a pretty standard settings (210 main, standard pilot jet, expanny, etc).

At the moment I'm thinking the problem is purely carb related, due to the opposite ends of the mix range coming into play between idle and full throttle. Do you think I'm heading in the right direction?

NEV · Guru

Needle circlip/groove position can be important too, often overlooked

Calum122 · Guru

I didn't think boysen made reeds for the dt. I looked everywhere for some. Which might mean they're hy tech which is what i've got in my bike. Nothing wrong wkth that though.

NEV · Guru

Boyesons do make reed petals for the DT's Callum, exactly the same, just a bit pricier than HY-TECH, that's why I went for the HY-TECH ones.

Calum122 · Guru

NEV wrote:
Boyesons do make reed petals for the DT's Callum, exactly the same, just a bit pricier than HY-TECH, that's why I went for the HY-TECH ones.

Couldn't find them anywhere!

but good to know.

Also make sure they are new mate. Reeds are serviceable items. And carbon ones are even more serviceable.

fused420 · DTR Senior Member

I had a play about with the needle position closer to when I rebuilt the engine, the circlip is in the centre groove atm, not the top as I previously thought. It can't hurt to have another play around with it though..

I don't get why the air screw needs to be all the way in for it not to bog though?

@Callum I haven't been able to find much info on them either, so you could be right there. Do they make much of a difference?

fused420 · DTR Senior Member

Im a slow typer, lol