65cc 2stroke won't start - please help

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65cc 2stroke won't start - please help

Hi there, I am new to this forum and am just hopeing that someone could give me some advise with a few problems I am currently having with a 2009 Cobra CX 65 (Similar to KTM SX65) I bought the cobra as a non runner from a friend relatively cheap, hoping that I could quickly get it up and running and make a little profit. When I purchased the bike it would kick over after some time but then run terrible while smoking quite abit, then foul the plug, bog and ultimately cutout. I then would clean the plug, tweak the carb and try again but with no progress. Next I went out and purchased a piston kit with a little end bearing and installed them, cleaned the carb, filter and plug. But since then it won't kick. I can tell it wants to fire up but just won't. If I try to bump start it, it gets closer to starting but doesn't start properly, bogs and dies. The plug is producing a spark and fuel is flowing in to the carb. So now with my limited mechanical skill I'm currently stuck as to what to do next and as I don't intend to keep the bike I want to be spending as little as possible to get the bike up and running again. Could you guys please suggest what to check next? and if you have any ideas what the problem could be? Any help would be greatly appreciated. Also the air filter is well used and the plug has been fouled and cleaned many times (I'm not even sure if the plug is the right one for the CX65 it definitely fits but may not be hot enough) Could it be as simple as just these causing my problems? I just don't want to spend anymore than I have to. Having already had to buy the piston kit, sprocket, transmission oil. I may just be lucky to break even. Many thanks in advance, James

Hi James, wow pity you didn't ask earlier, as I have said previously on these columns always go back to basics, An engine needs 3 things to run 1/. Fuel 2/. Compression and 3/. Ignition (a spark). If it wasn't running when you got it that's usually a sign (to me) that something mechanical is amiss. You've checked 1/. & 3/. (although we may need to go back to these) did you check 2?. Take the plug out and turn the engine over you should feel good compression, is it there? You changed the piston with a kit, what made you suspect the other one was wrong? You cannot just pop these pieces in there is more to it than that, honing the bores, ring gap etc etc.If you don't do these properly 2 strokes especially are liable to seize. I'm guessing here but I suspect you may not be getting enough compression, You might be correct with the plug but this will effect it more running, it should still start, look up correct plug on the interweb. Rough running may be just old fuel, or incorrect mixture, you did use new fuel didn't you. Is the oil mixed when filling up or does it have a tank? It is 2 stroke oil in it? Lets go from there. Oh one more thing, are you sure you put the rings in correctly i.e. right order, gaps not in line and right way round if an oil ring

http://kingcobraofflorida.com/Manuals/2009-CX65%20Supermoto%20Owners%20Manual.pdf   There you go my son, found complete manual with troubleshooting page 48, saves me waffling on You did use new gaskets and torque everything down didn't you? Always glad to help our cousins! Any other questions just ask.

I agree with oldboy, and would urge you to check through things in a systematic way, starting with cheapest first but: a two stroke that's smoking lots and running badly / not starting may well have blown its crank seals..

Don't think I'll bother answering any more of these Tappy, they ask you respond then, they disappear forever, waste of our time?

Yeah. My favourites are the ones that respond to a post with "I've got the same problem - how do I fix it?". If it's the same symptoms, you follow the previous advice and fix it. If it's not the same symptoms then it's not the same problem. FFS.

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