My 06 EC300 not running properly!

[ferguscawley]

You possibly have a warped cylinder head - are you losing coolant ? I have come across this on another EC300 where there was a tiny hole in the radiator which caused the bike to overheat sufficiently to warp the head.

Remove the head and check it.

[goose202]

re water on the plug - if the water pump was leaking enough that it could then get past leaky crank seals, there'd be the milkshake of all milkshakes in your gearbox oil surely?

[GMP]

Coolant on the plug now? I doubt from a leaky water pump seal. Coolant and 2-stroke oil will have a lighter appearance as well. Has the head been off, motor apart? I say likely because the hose clamps are not OEM. Its also possible that a head o-ring was pinched on installation in addition to the warped head mentioned. Go through the motor one thing at a time. Just look at your sight glass and drain the oil. If its not milky your water pump is fine, if its not low your primary crank seal is likely fine as well. What does your coolant look like, dirty/oily? Rapid pressure build up like overheating?

We bought a used 125 GG once that had pinched head o-ring from a botched top end job, same issues.

[ju571n]

Gearbox oil is milky as, so im sure the water pump seal is stuffed. Can it get in there from anywhere else? I have the motor out im going to do a bottom end rebuild anyway. There seems to be more than usual radial play when I move the crank up and down from the left hand side, it can be rattled if you lift it up and down quickly. Sound stuffed enough to justify a full rebuild? I will check out the head o rings. Can water leak through the base gasket?

[Disco_STu]

This motor sounds pretty sick. Milky oil can be from either going through deep water or the water pump seal leaking. Drain oil and flush first with diesel or kerosene, then run some cheap oil through it. put some clean and fresh oil in and run for a while, if this is milky then it is going to be the water pump seal gone.

When a two stroke does its crank seals in it will run rich. This is because the pumping efficiency drops and the engine loads up with fuel oil mix and so runs rich.

The roller mains on the left end of the crank are a good design idea but the execution is not so good. the weak link in the design is that the cage is nylon and gets brittle with age and heat cycles. The little bits of plastic cage separating the rollers break out and all the rollers fall to the bottom and then guess what happens.

The looseness in this bearing means that the crank does not run concentrically in the seal. So the crank is pushed hard up against the seal on one side and has a gap on the other side. To check the play in the crank properly you need to pull the flywheel off. The small gap between the flywheel and stator poles limits the amount of movement you will be able to feel.

Hope this helps.

[ju571n]

It seems the right hand side main bearing is ok but the left one is shagged, so she will still be getting a full rebuild. Upon taking off the flywheel it became apparent that the ignition could be contributing to the problem. It is very rusty and one of the coils is burnt out, which would explain why my lighting is not working...It still doesn't explain where the water is coming from though...

[skid jackson]

I'm still chasing a water in tranny condition in my 06 300. already tried the pump seal, kind of baffled at the moment. Other than that the bike seems to run fine

[ju571n]

The main problem with mine is water on the spark plug, but there still was water in the tranny as well...

[ferguscawley]

Originally Posted by ju571n

The main problem with mine is water on the spark plug, but there still was water in the tranny as well...

Water on the spark plug means :

Damaged or warped cylinder head and/or head 'o' rings
or
Cracked cylinder
or
Damaged base gasket allowing coolant to seep into crankcase and end up in the cylinder

Did you renew the base gasket(s) the last time you did a top end rebuild ?

[ju571n]

Well I have done a full rebuild (including a stator rewind) and it is definitely running a lot smoother now, but it still doesn't seem to want to do upper revs. The plug seems rather wet after I have run it for a bit. There doesn't seem to be anymore water on the plug, so thats a start!

I have tried:

-disconnecting the Highlight power wire, as this was something I read that was suggested to make sure the regulator was not playing up.

- Blowing the power valve breather hose out

- New plug

Any other suggestions? im getting very frustrated!