jamieson Posted May 4, 2010 Report Share Posted May 4, 2010 Hi there, Suddenly can't get my KT to fire up. Used to start 1st time every time no matter how long stood or what the temperature was. Now, after several kicks, will only run for a few seconds and then dies completely. Have checked the obvious; nice fat spark at the plug, fuel in the tank etc. There's no 2 stroke oil tank fitted and I have been premixing the fuel using fully synthetic 2 stroke at 50:1 ratio. Someone else told me recently they had problems using synthetic 2 stroke in their kh250 and so I wondered if that could be the problem with the kt? Any help appreciated Cheers Quote Link to comment Share on other sites More sharing options...
hewson Posted May 4, 2010 Report Share Posted May 4, 2010 Hi there Give the carb a good clean out , could also be the crank seals that need replacing ..... Quote Link to comment Share on other sites More sharing options...
woody Posted May 5, 2010 Report Share Posted May 5, 2010 Synthetic 2 stroke won't hurt your KT. I run mine on Castrol TTS at 50:1. Whilst I don't know what's wrong as it could be anything, one possibility could be that it is using whatever fuel is in the carb and then dying as the float bowl isn't refilling quick enough. You don't say whether it will start up again afterwards (before dying again) Could be the length of time it takes you start it again is due to the time it takes for enough fuel to trickle into the float bowl to start it. You could try switching the fuel tap off as soon as the engine dies and then checking how much fuel you have in the float bowl. If fuel flow is ok it shoulod be full. If it is a fuel problem it will be low/empty. Fuel tap obstruction? Tank vent partially blocked? Float needle sticking and not opening up properly? Doesn't seem like electrics as it doesn't sound as though it is running long enough for one of the electrical components to fail when getting hot. If it isn't fuel I'd try a new plug and cap as a start anyway, even though you seem to have a good spark. Quote Link to comment Share on other sites More sharing options...
jamieson Posted May 5, 2010 Author Report Share Posted May 5, 2010 Thanks for the responses, it looks like it's a fuel related problem. Will give the carb a good clean and put a filter in between the fuel tap and carb. I've fitted additional fuel filters on my other bikes and it's amazing how much crap can get past the fuel tap filter and into the carb. If the crank seals have gone can that result in back pressure through the carb? I ask because a couple of times it has backfired when trying to start it and fuel spills out from the 2 stroke oil inlet stub at the bottom of the carb. Thanks again for your advice Quote Link to comment Share on other sites More sharing options...
stork955 Posted May 5, 2010 Report Share Posted May 5, 2010 Whoa! have you got an unblocked lube pipe on your carb? If so -block it now! A rubber car type cap will work, or a bit of hose with a small screw in the end. Basically you dont want any air leaking in that doesnt go threough the carb. Cheers, Stork Quote Link to comment Share on other sites More sharing options...
belldane Posted May 6, 2010 Report Share Posted May 6, 2010 I had a similar problem with a Montesa backfiring while trying to start it. It would not hurt to check timing. It may not be the problem but try anyway and if it is not that you can eliminate from the other things you need to check Quote Link to comment Share on other sites More sharing options...
jamieson Posted May 6, 2010 Author Report Share Posted May 6, 2010 Thanks guys! Will clean the carb, block the lube inlet stub and check timing and see what happens. Did wonder why the lube stub wasn't blocked when I got the bike but up until now (some six months later) engine has been running fine! Cheers Quote Link to comment Share on other sites More sharing options...
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