DT125R ARCHIVE

dtr200691 · DTR Senior Member

Eating sparkplugs

NEV · Guru

Sounds like you're drawing air in from somewhere mate, you checket at the air intake and outlet for cracks or splits? Iknow that when I stripped my airbox down there was a split on the intake rubber that needed sorting. What years your bike btw, #270 for the mainjet seems pretty big.

dtr200691 · DTR Senior Member

It's 2003 mate that is well too big but like a say it's still running lean n av sprayed flammable stuff all ova that area if it wer sucking in air it'd rev higher

fused420 · DTR Senior Member

Are you sure its running lean? To much fuel kills plugs FAST, don't know about the other way round though?

dtr200691 · DTR Senior Member

It's going white tho not black n it's burning away the nipple wer you get your spark maybe not enuf 2 stroke??

FunkeyMunkeyDavid · Guru

i thought white plugs was dodgy cdi or coolant leaking inside the cylinder? are you loosing any coolant fella? check all your connectors and wires near the cdi unit? sounds more electrical to me confuse

NORFE · DTR Trusted Engine Builder

thatsa getting to hot, mixture to lean

http://www.gnttype.org/techarea/engine/plugs.html

An example of overheating is shown below. Note the dead white or gray insulator nose which appears "blistered." Electrode gap wear rate will be considerably in excess of that normally expected. This is often caused by overadvanced ignition timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean A/F mixture, a leaking intake manifold, or the use of a spark plug too hot for the application.

dtr200691 · DTR Senior Member

Not leeking coolant I have thought its electrics problem all along but cannot find the source. Ive got a 270 main jet on northe how much further can I go to try and even mixture lol it's drinking 26 to gallon as it is n just abet getting 60mph

NORFE · DTR Trusted Engine Builder

have you done all the restrictions ? reed switch what year is it ?

jet seems to big id put it back to std jetting and needle clip before you start any thing else

take it from there smile

FunkeyMunkeyDavid · Guru

was gonna say,i'm running a 270 main on my off road dt,but the aibox is cut like this

and its mildly ported too,runs about right. think norfe's bang on,set it back to standard and start from scratch...

-- Edited by FunkeyMunkeyDavid on Thursday 17th of May 2012 10:03:42 PM

dtr200691 · DTR Senior Member

Ye al derestictions done even inlet nt that it made a diference just had a brain wave tho in a crash I had b4 doing derestrictions I smashd the botom end of exhaust so welderd 2 pieces of curved 30mil stainles tube n from outlet to expansion so finking could b not enuf back presure bikes nt misfiring animur jus vibrates like made when get ova 8rpm dosent feel gud atall sounds n feels like its ova reving

FunkeyMunkeyDavid · Guru

what does it rev to fella out of interest? they do give a bit of vibe when they come on pipe,but shouldn't be excessive. if the shape of your pipe or the diameter has changed it wont help. dont know exactly how much grief that would cause tho? fly wheel is worth a check (is it tight,any play ect...)that would give bad vibrations... if its moved (loose woodruff key) it would give electrical grief...... confuse

NORFE · DTR Trusted Engine Builder

iv got my air box the same now and still on std jetting with the dep on and it runs mins from top to bottom and the blugs bang on

every bike runs difrent so its a game of t & e to find what works best

FunkeyMunkeyDavid · Guru

inlet manifold on ebay fella

http://www.ebay.co.uk/itm/Yamaha-DT125R-DTR-DT-125-Inlet-Manifold-/130699168237?pt=UK_Motorcycle_Parts&hash=item1e6e4709ed

the air screw is on the petrol tap side of the carb,small brass screw (no 30 in pic)

http://www.yamahamotorcyclespares.co.uk/spares/epc2.asp?modelID=9136&PageiD=7&m=YAMAHA+DT125R+++1990+CARBURETOR&uID=0

sure someone on here must have a pdf manual?

-- Edited by FunkeyMunkeyDavid on Friday 18th of May 2012 08:26:05 PM

dtr200691 · DTR Senior Member

Revs to 8rpm afta that am best changing up it hates goin ani higher. where is the flywheel do u have to drain oil to get to it? Fink my best bets paying you a visit norfe

NORFE · DTR Trusted Engine Builder

http://www.yamahascooterspares.co.uk/spares/epc2.asp?modelID=9057&PageiD=34&m=YAMAHA+DT125X++2005+GENERATOR&uID=0

number 1 is the rotor (people think its called a fly wheel but its not lol

its behind the plastic/alloy cover on the left side of the engine

no dont have to drain the oil !

where do u likve mate?

dtr200691 · DTR Senior Member

Near buxton mate oryt thought that were magneto will put 240 jet back in 2mz n keep look out for original intake manifold as had myn strippd finking it wer holging it back lol just made it run worse

dtr200691 · DTR Senior Member

Jus read up on posible causes n its said mixture incorrect adjust pilot air screw ani1 no wer this is? N cn any1 post a brief description how to change main jet please had garage do it in past

FunkeyMunkeyDavid · Guru

http://dt125r.activeboard.com/t41394490/dt125r-88-03-manual/

dtr200691 · DTR Senior Member

Cheers pal