sparky24 Posted October 31, 2013 Report Share Posted October 31, 2013 Hi there,I'm having trouble getting my KT 250 to run properly.It sounds when revved like it's gassed up and dosn't rev cleanly. I have had the crank seals replaced,had the carb overhauled by Motocarb Liverpool,had the timing checked,changed the spark plug,renewed the air filter (runs no different with filter in/out and checked the exhaust for blockage.There is plenty of compression but going to do a proper check tomorrow,and it starts up fine.I am running on pre mix at 50:1 using castrol 747 2 stroke oil I don't know what to look at next.Any tips, pointers ,ideas etc would be greatly appreciated as I'm dying to get out on her after buying and bringing her over from USA. Regards Steve (sparky24). Quote Link to comment Share on other sites More sharing options...
nelly1 Posted October 31, 2013 Report Share Posted October 31, 2013 is the exhaust ok try taking the rear pipe off and see if it revs any better Quote Link to comment Share on other sites More sharing options...
sparky24 Posted October 31, 2013 Author Report Share Posted October 31, 2013 I have taken out the baffle and removed the silencer and it's still the same. Quote Link to comment Share on other sites More sharing options...
totalshell Posted October 31, 2013 Report Share Posted October 31, 2013 whats the plug like.. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted November 1, 2013 Report Share Posted November 1, 2013 Check the conductor inside the HT lead where it connects to the plug cap Check the HT lead for touching the exhaust - I've seen a few KTs with melted HT leads Check killswitch and killswitch wiring (disconnect it at the HT coil end) Do you know if there was any motor work done before you got it? (it might not have the right length rear piston skirt) Are the rings worn out, or not sealing for some other reason? (two strokes can still start OK but then run in a way that makes them sound very rich if the rings are not sealing well) Did you run it before you got the carby overhauled? (ie did you get the carby overhauled because of the problem) Are you sure the start enrichening device is closing fully? Quote Link to comment Share on other sites More sharing options...
sparky24 Posted November 1, 2013 Author Report Share Posted November 1, 2013 Thanks for your replies , it has a new plug fitted and the kill switch has been replaced from the original to a Yamaha type push button. I had the carb overhauled because of the way it's running and has had a new choke plunger assembly fitted when overhauled. I don't know if any engine work has been done but I'm pretty sure it has an original kawasaki piston ,it has the letter A stamped on top. I will do a compression test which should indicate any wear,but it has decent compression when kicked over. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted November 1, 2013 Report Share Posted November 1, 2013 Thanks for your replies , it has a new plug fitted and the kill switch has been replaced from the original to a Yamaha type push button. I had the carb overhauled because of the way it's running and has had a new choke plunger assembly fitted when overhauled. I don't know if any engine work has been done but I'm pretty sure it has an original kawasaki piston ,it has the letter A stamped on top. I will do a compression test which should indicate any wear,but it has decent compression when kicked over. What about the HT lead and plug cap? Does it still have the original ignition keyswitch fitted (under the left side of the fuel tank)? A much better test of the rings sealing would be to look inside the bore for evidence of blowby (through exhaust port or plug hole or to take the head off). Compression tests give widely varying results on the same motor depending on how oily the rings are and how fast it is cranked over and for how many revolutions it is cranked over for. Quote Link to comment Share on other sites More sharing options...
sparky24 Posted November 1, 2013 Author Report Share Posted November 1, 2013 (edited) Hi there,the bike still has the original ignition key switch fitted,I removed the plug cap and cut back the ht slightly,you can turn the ht lead in the coil,I don't know if this is ok or not.I didn't want to pull out the ht lead forcefully in case the coil and ht are one part,basically is the ht lead replacable?? I did a compression test today,I kicked it over once and it showed 120psi,I repeated this a few times and got the same 120psi. I'm thinking the problem is more likely electrical,any ideas or thoughts are greatly appreciated. Regards Steve. Edited November 1, 2013 by sparky24 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted November 1, 2013 Report Share Posted November 1, 2013 (edited) If the conductor in the HT lead where you cut it was nice bright copper it should be OK. Plug caps can cause problems too and fitting a new one is pretty cheap. Some just keep turning even after they are fully screwed on because all you are doing is screwing the thread into the hole up the middle of the lead. Generally the cap is mainly held in place by friction between the OD of the lead and the socket in the cap. No you can't fit a new HT lead directly to the HT coil winding. Have you checked the LT wiring and the LT connectors for damage? If you still have the keyswitch fitted, you should do a test run with it unplugged at the coil end. You may have a problem with it's wiring or internally. Edited November 1, 2013 by feetupfun Quote Link to comment Share on other sites More sharing options...
sparky24 Posted November 1, 2013 Author Report Share Posted November 1, 2013 Thanks again for your reply,I will try a new plug cap,the ht wire was not bright copper,fairly dull,so to replace it would mean a new coil would it?they are both rare and expensive!! I will also diconnect the ignition switch and lights and see what happens.I have also been told that it could be the stators,there are three lighting,charging and primary,I guess these would also be rare and no doubt expensive. Quote Link to comment Share on other sites More sharing options...
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