gasgas ec300 engine problem

[jens]

hey,

I bought a gasgas ec300 from 2002. I been riding it 3-4 times but now i got some problems with my engine.
But now the engine got trouble to stay on when im not giving gas.
ive been searching for a while and i found out that when i remove the cover off the power valve the engine runs perfectly.

anybody got an idea what the problem could be?

(sorry for my bad english i speak dutch)

Jens

 

[GasGasDreamer]

But now the engine got trouble to stay on when im not giving gas.

Your pilot jet is dirty or clogged.
Another very weird thing happened to me once.
I adjusted the air / fuel screw while the bike was running.
All was well for an hour or so and then it started acting like there was some weird erratic electrical problem.
I replaced the plug and it disappeared.
But i am assuming that you changed the plug, cleaned the airfilter, didnt leave a towel in the intake boot, have good clean gas, and had sure your stator is dry..

 

[stainlesscycle]

i found out that when i remove the cover off the power valve the engine runs perfectly.

check for restriction in pipe/silencer

 

[jens]

Your pilot jet is dirty or clogged.
Another very weird thing happened to me once.
I adjusted the air / fuel screw while the bike was running.
All was well for an hour or so and then it started acting like there was some weird erratic electrical problem.
I replaced the plug and it disappeared.
But i am assuming that you changed the plug, cleaned the airfilter, didnt leave a towel in the intake boot, have good clean gas, and had sure your stator is dry..

yes i did check all of that. the problem also started while we where doing a trip. i changed the plug about 3 times.

 

[jens]

check for restriction in pipe/silencer

i will check this tomorrow. it might be possibel and it would also explain the problems.

 

[GasGasDreamer]

i found out that when i remove the cover off the power valve the engine runs perfectly.

do you mean you ride it with the cover off?

 

[GasGasDreamer]

check for restriction in pipe/silencer

i dont know if this can happen on mc but on cars the exhaust can look great but in reality the second inner wall collapses and the car will run for a little bit then die.
on a car you can use a vacumm guage to check for this. at first reading is normal then it starts to drop and continues to drop until it dies.

i dont thing the expansion pipe is a double wall.
the silencer should be easy to take apart and see.

best of luck.
please report back..

 

[jens]

do you mean you ride it with the cover off?

no i dont ride whitout it. i just whas searching the problem when i got home, and i thought there whas a problem whit the powervalve so i removed it and started the engine. then he whas running fine but when you close it he dies again.

 

[jens]

i dont know if this can happen on mc but on cars the exhaust can look great but in reality the second inner wall collapses and the car will run for a little bit then die.
on a car you can use a vacumm guage to check for this. at first reading is normal then it starts to drop and continues to drop until it dies.

i dont thing the expansion pipe is a double wall.
the silencer should be easy to take apart and see.

best of luck.
please report back..

yes, you explain kinda what happends. il remove the silencer tommorrow and check it out. tomorrow i wil report if this whas the problem or not.

 

[HuskyDude]

Isn't there a little vent tube coming from the Power Valve box? That could be plugged.

 

[Jakobi]

Isn't there a little vent tube coming from the Power Valve box? That could be plugged.

LHS PV has a drain that is generally sealed from the factory and the bike runs just fine with it sealed. Off the top of my head can't remember if the RHS has a breather or not.

 

[jens]

so i checked the exchaust, there whas nothing wrong with it.

i also checked my max rpm, it whas around 10600 but then he started to sputter. (is this because hes limited on cdi?)
also is it normal i can only ride 65km whit 1 tank?

any other suggestions?

 

[jens]

LHS PV has a drain that is generally sealed from the factory and the bike runs just fine with it sealed. Off the top of my head can't remember if the RHS has a breather or not.

checked that also it wasn't sealed.

 

[stainlesscycle]

also is it normal i can only ride 65km whit 1 tank?

any other suggestions?

depending on the environment, 65km is not out of the ordinary. if just trail riding it's a little low, if at race pace, it's a little high.. the best fuel mileage i've heard is about 100km. worst is about 50km.


good compression? float height right? jetting?

 

[jens]

depending on the environment, 65km is not out of the ordinary. if just trail riding it's a little low, if at race pace, it's a little high.. the best fuel mileage i've heard is about 100km. worst is about 50km.


good compression? float height right? jetting?

i got good compression, also the float heigt is good (16mm), clips off the needle is in the middle.

the jets are:

- main jet = 178
- stationair jet = 42

powervalve works fine.

the engine doesnt go to his max RPM (i think), now it is 10600. the engine also stutters when he gets to 10600 RPM.

acceleration is good, its also a new spark.

i think it might be an exhaust problem (might be a little blocked)

 

[stainlesscycle]

a stutter/not wanting to overrev at the top is usually slightly rich on the main.

i still think it's an exhaust blockage though. the pv cover in essence is just an extension of the pipe. if it runs better with the cover off, it has to be becuase of increased airflow, hence the blocked pipe...


but if you find a blockage and fix it, you will probably find it revs out better, and the main jet will be properly sized.


wasn't there some pipes with a catalytic in them????

 

[jens]

a stutter/not wanting to overrev at the top is usually slightly rich on the main.

i still think it's an exhaust blockage though. the pv cover in essence is just an extension of the pipe. if it runs better with the cover off, it has to be becuase of increased airflow, hence the blocked pipe...


but if you find a blockage and fix it, you will probably find it revs out better, and the main jet will be properly sized.


wasn't there some pipes with a catalytic in them????

it sure makes sence.
and no there where no catalytic.

we wil open the silencer and check for obstructions.

 

[Jakobi]

10600 is pretty good over rev for a 300. I don't think you're facing any issues with it not being able to rev.

How well does it take throttle with the powervalve side installed? I find it mighty hard to imagine that it would change the dynamic of the engine enough to make the difference between not running and hitting 10,600rpm. I could very well be wrong.

I'm not sure the engine will be liking all those revs just sitting on the stand either. I'm with everyone elses opinion that by opening the pv you've opened the exhaust allowing the engine to breath. Indicates to me thst its not breathing through the pipe somehow.

 

[wasp4banger]

i got good compression, also the float heigt is good (16mm), clips off the needle is in the middle.

the jets are:

- main jet = 178
- stationair jet = 42

powervalve works fine.

the engine doesnt go to his max RPM (i think), now it is 10600. the engine also stutters when he gets to 10600 RPM.

acceleration is good, its also a new spark.

i think it might be an exhaust problem (might be a little blocked)

Do you know what needle you are running and does it show any wear?
Where is your airscrew, how many turns out?
What elevation / air temp are you running it at?

I think that for Holland you may be running a little rich on the main jet and on the pilot jet, but the needle can affect the higher revs and airscrew also affect the idle.

 

[Jakobi]

hey,

I bought a gasgas ec300 from 2002. I been riding it 3-4 times but now i got some problems with my engine.
But now the engine got trouble to stay on when im not giving gas.
ive been searching for a while and i found out that when i remove the cover off the power valve the engine runs perfectly.

anybody got an idea what the problem could be?

(sorry for my bad english i speak dutch)

Jens

Just reading the inital post again..

How did the bike run when you first bought it and rode it 3-4 times? Has it ever been right?

It appears that you are saying that the bike will not idle. Most probable cause, rich pilot circuit. Try leaning it out on the air screw or bumping up the idle adjustment screw (lifting the slide).