gadget Posted May 26, 2011 Share Posted May 26, 2011 Hi All i hae a 1985 DT50MX CDI with a 1980 TY50 engine in, when you pull away all is fine then about half throttle is holds back for a while then goes well again, as long as you keep the revs up its ok. (like getting starved of air/petrol) i have cleaned carb out cleaned jets and blown out all holes, have new air filter and spark plug and coil fitted( secondery high resistance 6Mohm) ( was playing up before i fitted these). it kicks over first time, have checked for air leaks but cant find any, has had an engine rebuild about 1000 miles ago , all was working fine a year ago ( has been in shed since then , just been getting it ready but cant put my finger on the problem any ideas from the experts. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 26, 2011 Moderator Share Posted May 26, 2011 I know you have cleaned the carb but it does rather sound like a blocked pilot jet. I assume it starts ok because you are using the starter (choke) and I assume it will rev ok with this in operation but the trouble starts when you switch off the choke? Link to comment Share on other sites More sharing options...
gadget Posted May 27, 2011 Author Share Posted May 27, 2011 Hi it starts without choke, if i turn choke on it dies, have had all tyhe carb and jets out cleaned and blown out with compressed air, still scratching my head. going to have a look at the electrics at the weekend, would a bad earth couse this problem ? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 27, 2011 Moderator Share Posted May 27, 2011 Hi it starts without choke, if i turn choke on it dies, have had all tyhe carb and jets out cleaned and blown out with compressed air, still scratching my head. going to have a look at the electrics at the weekend, would a bad earth couse this problem ? your problem sounds carb related to me, first off it shouldnt start easily from cold without choke. has the main jet come unscrewed and fallen off? or the throttle valve needle...is it clipped securely in the right slot? Link to comment Share on other sites More sharing options...
gadget Posted May 27, 2011 Author Share Posted May 27, 2011 Hi think main jet is there and tight but will check again a check size, i did notice that the needle does move about a lot left to right and also a little bit up and down. it seems to be held in by a washer sort of thing and inturn this is held down by the return spring, will check over weekend thanks and will let you know the outcome.many thanks Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted May 27, 2011 Moderator Share Posted May 27, 2011 Sounds like you're on the right track there Gadget. Link to comment Share on other sites More sharing options...
gadget Posted May 27, 2011 Author Share Posted May 27, 2011 hi had carb apart, all parts present. needle jet has 059 on it, main jet 105RD (book said 88) needle jet has 80 on it (i have no refrence to this in manual).float level correct , pilot jet unable to read clearly but think it looks like 40. teikei carb think its a Y14p. bike still starts without choke from cold and stalls when it put on. tried to adjust pilot air screw . screw in till faulters then when screwed out i ended up unscrewing completely ( end of thread)and it still runs. any ideas ? air filter is stock and new ,checked connecting hose for holes secured jubillee clips, when riding it starts to hold back , if youkeep bliping the throttle it picks up power and goes , if you keep it in the higher reves it goes good. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 27, 2011 Moderator Share Posted May 27, 2011 Hi think main jet is there and tight but will check again a check size, i did notice that the needle does move about a lot left to right and also a little bit up and down. it seems to be held in by a washer sort of thing and inturn this is held down by the return spring, will check over weekend thanks and will let you know the outcome.many thanks Clearly there shouldnt be this movement, make sure the clip is in the right groove and is also beneath the washer you mention, that washer has a bent tab which should locate in a slot in the throttle valve thereby keeping the cable nipple securely in its place, if it isnt this could result in the movement you describe hi had carb apart, all parts present. needle jet has 059 on it, main jet 105RD (book said 88) needle jet has 80 on it (i have no refrence to this in manual).float level correct , pilot jet unable to read clearly but think it looks like 40. teikei carb think its a Y14p. bike still starts without choke from cold and stalls when it put on. tried to adjust pilot air screw . screw in till faulters then when screwed out i ended up unscrewing completely ( end of thread)and it still runs. any ideas ? air filter is stock and new ,checked connecting hose for holes secured jubillee clips, when riding it starts to hold back , if youkeep bliping the throttle it picks up power and goes , if you keep it in the higher reves it goes good. Check and double check this main jet size, 105 is a lot bigger than 88 although 88 sounds a very odd size to me, normally they go up on steps of 5 I think Link to comment Share on other sites More sharing options...
gadget Posted May 27, 2011 Author Share Posted May 27, 2011 hi the washer in the to is over the needle but the washer is a y shape , all three sides are angles down and the spring sits on top . the needle has some room to move . the clip is on the bottom setting on the needle ( only 2 settings)the jet size in the hanes manual said 88 but use to run on these settings about 2 years ago before it got stripped for restoration ( seemed like a good idea at the time )maybe time for another carby Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 27, 2011 Moderator Share Posted May 27, 2011 hi the washer in the to is over the needle but the washer is a y shape , all three sides are angles down and the spring sits on top . the needle has some room to move . the clip is on the bottom setting on the needle ( only 2 settings)the jet size in the hanes manual said 88 but use to run on these settings about 2 years ago before it got stripped for restoration ( seemed like a good idea at the time )maybe time for another carby so are you saying the washer is standing on the edges of a bent down part and therefore not sitting flat on the throttle slide? I am not familiar but I have to question this. Perhaps it should sit flat with the bent edges facing up and the spring sitting inside of these bent edges?...That way there would be no up / down movement of the needle? Link to comment Share on other sites More sharing options...
gadget Posted May 27, 2011 Author Share Posted May 27, 2011 Hi, Will turn washer over tommorow and give it a go. Cant find this particular type of washer in the manual? Anyway thanks, will post result! Link to comment Share on other sites More sharing options...
gadget Posted May 28, 2011 Author Share Posted May 28, 2011 Hi.turned washer other way up and needle seems more secure, choke now works, still looseing power so disconected filter at carb, re connected and tried withpout filter still going strong put filter back in and problem came back, yam filter was brand new of the bay , purchased a ram filter and cut to size fitted and bingo were back in buisness, must have been conbination of duff filter and carb notput back together properly. many thanks for you advice. cheers nigel Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 28, 2011 Moderator Share Posted May 28, 2011 Hi.turned washer other way up and needle seems more secure, choke now works, still looseing power so disconected filter at carb, re connected and tried withpout filter still going strong put filter back in and problem came back, yam filter was brand new of the bay , purchased a ram filter and cut to size fitted and bingo were back in buisness, must have been conbination of duff filter and carb notput back together properly. many thanks for you advice. cheers nigel Yam filter may have been OK but as you say the jet is bigger than it should be...something to consider? Link to comment Share on other sites More sharing options...
gadget Posted May 28, 2011 Author Share Posted May 28, 2011 never gave it a thought about filter and wasent aware of jet size , will know next time, will be a bit more methodical taking things apart next time. cheers Link to comment Share on other sites More sharing options...
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