My 06 EC300 not running properly!

J

ju571n

New member
Just purchased the bike and it doesn't seem to run right.

It just stutters when trying to get in the upper revs. The low end seems good but that is about as good as it gets! I reckon I could run faster than it when it gets to the stuttering part!

It is running a 175main, 38 Pilot and N1EG needle on the second clip (tried 3rd also). Can you guys give me any advice on why it wont rev out properly? Is the main jet too lean?

I live in Australia. 0-1000 elevation. 25-30C

any advice would be appreciated. Cheers.
 
It could anything, jetting, crank shaft seals, plugged exhaust, and on and on. This does sound like what my 250 did with a bad ignition. Put an inductive timing light on your bike, and see that the ignition advances with an increase in RPM. My defective ignition advanced to midrange, then dropped back to no advance. It ran exactly as you describe.
 
The little nipple on my spark plug was loose last time I rode and the bike ran as you describe.
 
My EC300 ran like this when my power valve was stuck open(or shut?) . The nut holding the PV actuator arm had fallen off.
 
My guess is power valve is staying shut - mosre thabn likely due to the linkage arm coming off - remove rhight hand side power valve cover (you will have to remove exhaust front pipe first) and see if all is OK in there.

Fergus
 
I think it's the crank seal that is the problem, caused by worn main bearings! There is about a mm of movement when I move the flywheel up and down. Does it sound like it would be the cause? It also seems to be smoking a lot and the plug was pretty oily when I pulled it out..
 
Revved her in neutral with the plug in finger tight. Heaps of oil came out the plug hole....crank seals it is by the looks of things.

assgas001.jpg


assgas002.jpg
 
That won't tell you anything. A rolller crank bearing as used in the GG has some detectable radial play when the flywheel is moved up and down, even on a brand new bike. A bad crank bearing will also cause more vibration and a roaring noise from the lower end. Remove the flywheel, if the seal is bad you will see evidence of it in a leak. If the flywheel side seal is bad, it will usually have lean symptoms from sucking air. This does not sound like your problem. If the primary seal is bad, it will smoke really bad, much worse than rich jetting.

Think simple at first. Check your float level, float valve, and overall carb condition, from what you describe it just sounds way too rich on top for some reason. Reeds next, and go through your electrical connections including the HV coil wire. I see by that pic the plug cap has been changed, perhaps an attempt to fix this problem and maybe not correctly. Check/clean the coil ground to the frame and the stator plate to the case. Lastly CDI and coil if you can swap with someone to troubleshoot.
 
The oil does not look like 2 stroke oil coming out of the spark plug hole. It is more the consistency of gear oil. It is blowing excessive amounts of smoke that appears to be more whiter in colour. There was also water on the plug which to me indicates that the water pump seal is broken also leaking through the right side crank seal. I have changed all the fuel so I dont think the water could have come through there.
 
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.
 
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?
 
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.
 
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?
 
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.
 
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...
 
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 said:
The main problem with mine is water on the spark plug, but there still was water in the tranny as well...
Click to expand...

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 ?
 
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!
 
You must log in or register to reply here.

Similar threads

H
Needle advice
2
Replies
25
Views
24K
Houghton
H
B
Jetting for 2007 EC300 - something isn't right
Replies
2
Views
3K
(F5)
(F5)
G
2001 EC250 Jetting
Replies
12
Views
5K
(F5)
(F5)
J
Gas Gas Ec 300 2004 Carb setup issue
2
Replies
32
Views
16K
JayStallion
J
L
Spark plug fouling
2
Replies
35
Views
21K
swazi_matt
S
Back
Top