sword70

I managed to check out your ideas and bypassed the brown wire direct to the battery and everything worked as it should and to top it all the bike flew through its mot today after not being on the road for about 7 years so well chuffed. Noticed since bypassing the brown wire all the lights are allot brighter and the bike starts better than it every has but now the pressure is off as its mot'd i will track down the fault then fix and put back to how it should be. Thanks for all the advice, i now have one very happy 16 year old about to hit the road solo for the first time tomorrow.

There is a brown and brown / white wire on flasher relay, brown is power from ignition switch, brown and white is return up to the indicator switch. Will give your sugestion a go , cheers

I have been struggling to resolve an electricla problem on our DT 50 and am now stumped. I get the bike running and check brake lights, headlight, horn, neutral light and rear light and all work great, as soon as i put the indicators on most of the time the indicators work as they should but always make all of the lights flash in time with the flasher relay and also the horn pulses in tune with it as well. Most of the time indicators alone work fine but on occasion they will not work at all which doesnt help either. I have cleaned up all the contacts i can get at with my dremel, checked the loom and replaced large ammounts of corroded wire and made a seperate earth loom feeding the rear lights and then another for anything up front needing an earth using all new wire and connectors. Have also taken apart as many switches as i could and cleaned up contacts there, only things i havent managed to clean up are a couple of the multi block connectors on the femal side as i dont have a dremel bit small enough to get in there. Would like to get bike up for mot asap and this is holding me back, any advice no matter how obvious would be appreciated

Finally my back is all good now so had chance to play a bit more on the old DT. After stripping both carbs down and re-checking everything i spotted a slight groove in the float needle and as i cant find a replacement at the momment i used fine wet and dry and carefully removed the groove, double checked choke was ok and blew all passageways out and rebuilt. Managed to get bike going again and rode it around a bit, seems a little flat on power so been tweaking the carb and still not happy as mixture screw has very minimal affect but getting closer now as spark plug is alot less sooty borderline clean just not that nice brown tinge to it just yet. Bike still has a habit of flooding now and then if you failt to start it after a couple of kicks or if left to idle for too long and you stall it but as a rule it will start first kick most of the time. Tried a mock up of the Dellorto phva 17.5mm carb i purchased and although at a push it will fit i need to do a few mods inlet side and get a longer throttle cable so taking my time on that. Just out of interest i called a local yamaha dealer and they are on the case to track down any NOS spares kicking around mainly carb repair kits or complete new carbs and also looking at what if any other carbs may have been fitted to the DT or equivalent bikes as ideally i want this bike to be 100% reliable and would be nice to stock up on spares or swap the teikei carb for a mikuni or similar that is easier to get spares for. If all else fails i am on the look out for an independant bike repair shop in the Swindon / Oxford area and will let someone who does this all day take a look before i throw all my toys out the pram lol :-)

Well back still messed up so spent a couple of days trecking through the internet trying to find repair kits and got nowhere. Settled for ordering a Dellorto 17.5 mm carb new, should be here tomorrow so will get playing once back is better. Will probably just drain engine oil and replace, mates got a waste oil burner so always happy to take old stuff away no matter what extras it has in it :-) I am a bit stubborn so will be stripping both teikei carbs down and measuring jets etc and searching some more for jets and needle to get them both back working properly.

Ah, good move, would have overlooked that and killed the motor :-)

Think i might have sussed it a little, bike keeps flooding very quickly. I have 2 carbs both different jets in etc but otherwise identical, removed plug, cleaned it and sprayed easy start on and blew with airline to help remove previous fuel then refitted. Bike seems to start relatively easier and rev's although a bit spluttery then dies, pull plug out and its wet. At the momment it only runs for 15-30 seconds before dying and not starting again until plug cleaned and refitted. Struggling to find off the shelf carb repair kit or jets without measuring threads and dimensions so going to hunt a bit more, been told possibility of new carbs still available from Yamaha at about £130 but local yamaha dealer couldnt get me off the phone quick enough and not very helpfull. Other alternative is fitting a new dellorto 17.5mm carb so that might be my next step, just trying to get info on these carbs not having a choke fitted and how to rig one up before buying Thanks for all your help so far, i think i have been working on too many vehicles the last couple of weeks and getting a bit blind to the obvious, pulled back aint helping either :-)

Have 2 new plugs and think the old 2 kicking around so might try again tomorrow. Pulled my back out 5 days ago so this endless kicking the bike over is taking its toll, will get my son to pull his finger out and get kicking the bike over for me while i mess with the carb adjustment and try swapping the plug over to see what difference it makes.

I have 2 DT 50 MX's ones a 1989 other a 1991 model and both are cdi with 65cc kits on and non stock reeds, stock exhausts. After tearing one to bits and cleaning up all electical connections, replacing coil, spark plug, strip and clean carb etc i finally got one up and running but it struggles to tick over for more than a few seconds, rev's a bit spluttery then gives up and stops and then takes several kicks to get going again. I have double checked the carb is clean and been blown out with compressed air, set the left screw 1 1/2 turns out as per haynes manual but can find no info on setting the throttle stop screw at all. I have done a compression test and that is perfect, nice spark from the new plug and coil so thinking i have carb or fuel issues and trying to set it up as close to stock as i can to get it running and warmed up before tweaking, i tried adjusting throttle stop screw in or out about 1/4 turn at a time several times to see if that helped and still no reliable starting and running. Carb's i have are both Teikei 14mm ones with 40 pilot jets, both needle jets have 80 stamped on them and one main jet has 100 on it , other i couldnt read so according to haynes manual my pilot jet is correct but main and needle are not stock?? Been trying to find carb repair kits for these and drawn a blank, ideally would like new gasket, float valve, jets etc and kinda start again with a clean slate before tweaking but no joy so far. As this bike will be for my son to travel to and from work over the next few months i want it to be as reliable as possible so am calling out for any help or info above and beyond what haynes tells me please. I am not against fitting an aftermarket carburettor onto this or sending the 2 i have away to be sorted if it all gets beyond me so any advice to get this one running sweet would be much appreciated.

AH cool, will do

Hi, Newish to the forum so thought i had better introduce myself. Names shane, i live in oxfordshire, uk and main hobby is working on classic vw's but as son turned 16 recently and couldnt bring myself to buy some bike for him i had never heard of i purchased a pair of DT50mx's and a Suzuki TS50ER to tinker with. Last time i had any form of motorbike was back in 1990 so these bikes have been a bit of a learning curve and testing my memory a bit :-) Will try to get some pics up on readers rides as soon as the bikes are a bit more complete.

I need a little help to clear up some confusion, i recently purchased 2 DT50MX's for my son to rebuild prior to a cbt test and one piston cracked whilst kicking it over and the other is badly scored around the ring. I have been trying to size up the pistons / barrels to order a new piston set but sizes are a bit odd or i am missing something. One bike has had a big bore kit fitted that the barrel weighs about half as much as the other and top of the piston has 0.50 stamped on it, as close as i can tell the piston is 44.4mm wide and bore of barrel 44.5mm, only have a set of vernier calipers to measure with and this so as close as i can get in accuracy. Other bike has heavy barrel supposed to have been standard but doesnt look like it to me, piston is about 42.7mm wide and barrel 42.9mm. I had assumed as the stock size is 40mm and big bore usually 43mm, making the heavier one around 5 times oversize and lighter one almost 3 times oversize not the 0.50 the top of the piston says???? Am i missing something or maybe measuring it wrong? i would have thought sizes would go up 40mm, 40.5mm, 41mm, 41.5mm, 42mm, 42.5mm, 43mm, 43.5mm etc give or take a fag paper allowing for wear and tolerances. Wither way its either around £15 per bike for piston if i can get my head round this or £50 per bike for barrel and piston kit so worth a little research and screaming help for advice :-) Thanks in advance for any heads up info on this lot