V
Most likely a wiring fault, have a look behind the headlight cowl and make sure everything's in the right place.
as you've just brought it i assume you dont know the history of the bike ? anyone could have messed with it
have you got a Haynes manual?
is this a bright orange supermoto by any chance ?
Hi All, unfortunatly iv had to sell my DT125R
on better news iv passed my DAS so have a new bike meet Hettie 1998 CBR 600 F3 108bhp completely standard when i got her with 16000miles on the clock and one owner. have since got a black widow exhaust and changed a few thinks mostly look wise
i will buy another DT when funds allow probably next summer when i want to go green lane-ing.
if anyone buys my old bike or ends up with reg X6**BAM keep in touch! or PM me
BUT i Will be back 
well im actually debating weather im just panicking,
head and barrel skimmed and copper gasket with copper seal torqued to 22nm. the water has dropped in the rad to what i filled it up to, water is just sitting below the rad neck, and don't seem to be losing anything more, that's probably just where the water level is set.
like i said im probably just being a idiot and lacking faith lol. i'll see how it goes for a week and keep an eye on it,
Update,
went to go get a maccy d's for lunch lost a bit of coolant, so im afarid its still not done anyway got a second head now so ill go get that skimmed and the barrel checked, why are these such a bast**d to seal done x amount of 2 stroke head gaskets never had a leak., yet the dt is a pain. so im just going to go on the assumption that things are warped somewhere, at least i got a geunuine head gasket floating around now. the head gasket should show where the leak is hiding .
i think its safe to say yamaha should have used O rings instead of steel gaskets like all there other 2 strokes, funny that iv never seen a AM6 or a rotax 122 (not yammys obv) head gasket leak there both oring'ed, i feel a experimental project comming on
has anyone done it before ?
http://i44.photobucket.com/albums/f21/tom_smith7/IMG-20160412-WA0001_zpsrdcpssxh.jpg
So i got all my bits and have all been fitted. went for a 40 mile ride last night no leaks and no need to top up coolant,
on the way to work today 30 mile trip let bike cool coolant is just under rad neck so possibly just working out air bubbles so probs lost 5-10ml
this is using the copper gasket with copper sealant "spray a gasket" type of stuff
see how it goes on the ride home 
UPDATE,
had the head checked by a engineer buddy and its all flat so no warpage.
the workshops theroy for the blown head gasket.
in normal operation the thermostat regulates and pressurizes the system as @Calum stated maintaining a optimal temperature,
without a thermostat and having a free flow the "cold" coolant from the rad is being dumped into a boiling hot engine causing " thermometric" stress over time you end up with unevenly cooled parts of the head and develop hot spots "most likely over the exhaust port" this causes the aluminum to expand quicker than other parts and essentially crush the head gasket in small places. basically a slight bulge in the head surface. the engine then cools and the aluminum in the head then returns to normal, unfortunately the gasket cannot, so when you next start the engine from cold the gasket then blows past the weakest point your crushed head gasket !
i relise @Calum you have said this earlier doesn't hurt for a second opinion. but thank you i wouldn't have chased the thermostat route if you hadn't have clocked on to it
well parts should be here tomorrow including a new THERMOSTAT! so fingers crossed
cheers lads
after research and reading on many car forums iv decided to go with a copper head gasket with a bit of hylomar universal blue and a re skim on the head... depending on what the engineer says will double up the base gaskets. hopefully that will be the last time i hear of a leak.
with the help of the new thermostat as well
will probably take some pictures when putting it back together wont be till around the 20th of this month though
just having a thought about copper gaskets again,
i was sure copper reacts with aluminum so i had a quick search on the net.
"Aluminum will be very susceptible to galvanic corrosion in contact with copper, assuming that the two metals are also in contact with a common electrolyte (such as water with some ionic content.) Almost any text or handbook on corrosion will have galvanic series table. The farther two metals or alloys are separated on the table, faster the corrosion of the less noble of the two will be when they are in contact."
location of quote http://www.finishing.com/78/97.shtml
so surely copper head gaskets are a bad thing, also copper doesn't and wont compress like the OEM gaskets do so there cant be any imperfections on ether surface,
but then i think copper washers are used for air and water tight fittings as a "gasket" as such so copper does have its sealing quilatys
so my question is the pros and cons of copper good or bad ?? what would be the advantages over the OEM gaskets.
maybe is should start a new thread ??
Thermostat has been ordered from yambits, i had no idea it could cause such adverse effects ....
I'm going to go the copper head gasket route give it ago... Whats the worst that could happen 
Yeah the heads a bit battered ill stick a post in the wanted section for a replacement.
Will I be ok to re skim the head do you think how far from detonation am I thats the question....
And the problem has been found @Calum & @Biker_123 you were right! tiny head gasket leak !
http://i44.photobucket.com/albums/f21/tom_smith7/IMG-20160409-WA0001_zps9vlrakjd.jpg
http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_10_Pro_zps1cmucvrw.jpg
http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_01_Pro_zpsxynp8je6.jpg
http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_07_Pro_zps0eccyuwx.jpg
so what do you guys reckon go for another skim this heads already had 3 passes and the barrel 2 so that will be 5 thou taken of i would have thought?
also is it one of the guys on here selling the copper head gaskets on ebay? i know older engines used to have copper gaskets... are the rated highly for the use on DT's ?
as always advice aprecated
i agree have always used Athena gaskets just have a bigger budget than usual, best spent on gaskets or i'll only go and spend it on something useless otherwise ahah
i have always run my bike without a thermostat, the temp needle has sat nicely about a quarter of the way into the "running zone" no matter how much its being thrashed. full gasket set so that will be replaced as well anyways,
iv had a few head gasket failures on some of the off road bikes and the DT all usually pressurize the system eventually overwhelming and opening the rad cap and dump the coolant into the expansion tank till it overflows, can usually tell with the bulging pipes above the thermostat. and the water puddle on the floor and the exhaust fumes in the rad.
this issue unfortunately doesn't show any of the tell tale signs. possible pinhole size leak in the head maybe.
im not a fan of products such as rad weld and wonder weld etc.,... but might run a bottle through it just in case there is a pinhole leak in say the coolant pipe which runs across the front of the engine or behind a exhaust stud??
is re torquing the head a must. logic tells me once torqued correctly at cold the clamping force should only increase with the metal expanding when hot ? so surely there would be no way of it become slack ?
anyways as always thanks for the advice
