65cc 2stroke won't start - Please help me

[Guest]

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

[Fozzie]

Vacuum hoses all properly connected?

How was the compression before the kit went on, and how is it now?

Also is the carb set up properly? Is the mixture set correctly? And is oil mixing with the fuel as it should be?

Quite a lot of things can hold a 2-stroke back. Especially the smaller ones!

Also, welcome to the forum.

[Joeman]

Have you tried with the air filter removed?

Lots of smoke and fouling plugs suggests its running too rich a blocked air filter won't help that!

[Classickid21]

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

 

REPLACE CRANK SEALS

[Classickid21]

Have you tried with the air filter removed?

Lots of smoke and fouling plugs suggests its running too rich a blocked air filter won't help that!

 

(air filter on 2 stroke bikes correct me if i am wrong but aren't some oil coated/foam air filters) Maybe reeds need a clean too clean all hose's out but i still think its CRANK SEALS

you can usually tell alot about a engine by the spark plug

[Joeman]

yep, could be the crank seals - the smell will be different - wont smell like burnt two stroke, it will smell like burnt gearbox oil

[Fozzie]

Depends which/how the seal goes, as you can lose crank pressure without the leak, which makes it a real pig to find

It should still run, just very badly unless they let go totally.

[Classickid21]

yep, could be the crank seals - the smell will be different - wont smell like burnt two stroke, it will smell like burnt gearbox oil

 

noticed on two strokes Trimmers they smell like lavender (flowers) lol tbh they are only a few quid to buy so why not replace them and piece of mind then.

[Adam]

What sort of condition is the battery in? I'm sure I remember reading something on here that if it's not in tip top condition it won't give you enough of a spark to start the engine.

I could also be very wrong but if you can get hold of a multi metre it won't cost you anything to check it.

[Joeman]

Probably won't have a battery being an MX bike

[Classickid21]

Any updates?

[Scud]

Put a new plug in it firstly, always start there with a 2t crosser.

After that I'd look at the main jet in the carb and perhaps drop it a clip or two to start with, if not then a smaller main jet.