DTMaxy Posted September 21, 2018 Share Posted September 21, 2018 Hi All, Got a DT400mx import last month, its a little dream of a bike in good baseline nick. Got a bit of work to do yet though before I can justify getting the paint & decal work sorted. It starts perfect and idles fine, the trouble is once it goes onto main jet it bogs out atrociously. Done a bit of minor tinkering ie. new plug & air filter, but to no avail. Took it up the road the other day (in third) and turned the fuel tap off for a brief moment and there was a short burst of power which suggests an excessive fuel flow. Got a carb referb kit to fit to see if that will sort it (with float height setting check). Thing is the carb has a lot of new looking screws & fittings on it as though someone's been in there before. So prior to performing "surgery", my questions are; 1) is it possible that there is too much oil going in on the auto lube? 2) could this be a crank seal issue & what are the classic symptoms of seal failure? 3) been hearing a lot about crap original CDI etc. any truth in this? Got a lot of faith in old DT's, the 175's & 250's both have a great reputation and I had a go on both in me younger (wayward) days in the 80's with fond memories. This is my first venture with owning a stroker and was anticipating simplicity on the engine front so if anyone has had similar DT400MX experience please feel free to share, Will update once I've fitted the carb kit & checked float height. regards Max Link to comment Share on other sites More sharing options...
blackhat250 Posted September 21, 2018 Share Posted September 21, 2018 Hi max" ,the CDI"s [OEM] are ok, am running the original , i had the Rex speedshop settup. and it failed , [ its him that says the old cdi"s are crap] , i told him it failed ,and his only reply- "weve done an upgraded version" ,so i said trade the old one against one,= No reply, So, back to the carb,,change the jet setter,[immulsion tube] and needle, as if they are worn ,more fuel get sucked thru ,. what colour was the plug ? ,,, Read this. see what i mean , https://yamaha-enduros.com/index.php/forum/performance-improvements/7305-rex-s-electronic-ignitions Link to comment Share on other sites More sharing options...
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