Gas Gas ec 300 poor power

J

jarrodw

New member
Hey guys

I have recently bought a secondhand 2007 Gas Gas ec 300. When I first rode it I was pretty unimpressed with the lack of power. I mean this is a 300 cc 2 stroke and I can't even pop a wheelie with it. When I reach higher RPM's the bike sounds similar to a 4 stroke. And I seem to have more power when I use 3/4 throttle rather than full throttle. Is this bike supposed to be under powered or is it supposed to be a real bullet?

Here is what I can explain a little better. When I ride the bike I don't get that surge of power that all 2 strokes have, its as if the "power band" doesn't kick in. Their is no sudden burst of power, but more of a continuous "lack thereof power". I have been advised that it is the power valve stuck or that I have clogged Jets.

I have tried the following so far to try fix the problem. I removed the entire Carb today and cleaned it out with a toothbrush and petrol. Petrol looked more like oil when I was done cleaning it haha. I changed the spark plug, cleaned the air filter and removed the Petrol out the tank and replaced with a new tank, using a 50:1 ratio. But the bike is still the same. No power band kicking in.

Does anyone have any ideas what could be the problem with it? I live in South Africa and Gas Gas is not a big bike here at all. 9 out of 10 bike shops won't even look at the bike due to a problem sourcing spares. If I know what the problem is I can get a bike mechanic to have a look at it and just order parts of an online shop.

I am a student so I am looking for the cheapest way to fix this.

If you need any more info just shout.

Regards
Jarrod
 
Powervalve stuck shut or disconnected, jetting rich(very rich), float level too high, reeds bad, coil/ignition issue. These are the first things to look at and rule out. Also, FyI and for that of your local shops, the Keihin carb and Kokusan ignition system are the same as that used on KTMs and many Jap bikes. No exotic parts here. If you have basic knowledge and mechanical abilities with 2 strokes, it should not be that hard to figure this one out.
 
I have an '01 that had the same issues. It turned out to be the float level was too high and the jetting to rich. Would not idle at all until I cleaned the carb and set teh float level corectly.

Also check, your muffler packing my be full of oil and need changing since it probably is runnig way to rich. That also has an effect on it's ability to idle. After doing all that, it idles very well, pulls cleanly from low RPM, and is very snappy. Wheelies easily.
 
I'd pop a fresh spark plug in to start with, I spend a whole afternoon trying to jet around a faulty plug (felt sooooooooo stupid!). Check power valve operation. Check jetting not too rich.
 
Not saying you don't have other problems or that you won't feel a hit when the power valve does open. But remember GasGas has one of the best operating power valves out there. You might not feel a real big hit compared to others.

It's just smooooooth.:D
 
Ok so can i go around doing this? where do i start? I am new at all this and dont know much. I cleaned out the carb yesterday and replaced a new spark plug.

now when i put the fuel on the petrol just runs out a the side and bottom of the carb.its coming out the airhose 1 and 2. part 22 and 23 in the manual of the carb.

any idea what i did wrong? thanks
 
jarrodw said:
Ok so can i go around doing this? where do i start? I am new at all this and dont know much. I cleaned out the carb yesterday and replaced a new spark plug.

now when i put the fuel on the petrol just runs out a the side and bottom of the carb.its coming out the airhose 1 and 2. part 22 and 23 in the manual of the carb.

any idea what i did wrong? thanks
Click to expand...

Check you did not dislodge your float needle (rocket ship looking thing) that sits in a brass sleeve behind the float.
 
yes i thought i might of done something inside their. this is the bottom half of the carb tight? that has twp black objects that are called the float?

Really new to this stuff so would appreciate all the help i can get:o
 
jarrodw said:
yes i thought i might of done something inside their. this is the bottom half of the carb tight? that has twp black objects that are called the float?

Really new to this stuff so would appreciate all the help i can get:o
Click to expand...

Correct. Remove bottom of carb to check.
 
GMP said:
Powervalve stuck shut or disconnected, jetting rich(very rich), float level too high, reeds bad, coil/ignition issue. These are the first things to look at and rule out. Also, FyI and for that of your local shops, the Keihin carb and Kokusan ignition system are the same as that used on KTMs and many Jap bikes. No exotic parts here. If you have basic knowledge and mechanical abilities with 2 strokes, it should not be that hard to figure this one out.
Click to expand...

Read this again..


Check the powervalve action. remove RHS powervalve cover and run the bike on the stand. The actuator should be closed at idle with some light tension against the stop. You'll then see it open as you wick the throttle. You should notice if somethings wrong. Search the forum for powervalve and you'll get pleanty of pics.

Jetting! My best worst friend.. How does the bike run? Is it breaking up under throttle or is it just weak power. As per Kegs post. Look at jetting 101. Have a look at your plug, spooge, etc

No point jetting a worn engine though. Check piston through exhaust port, inspect reeds. Do a leak down test if you can/compression test.
 
I went through the exactly same thing on my KTM 250 xcw a couple of weeks ago. I adjusted jetting, checked the spark arrestor, reeds, and compression, but it was all fine. Then I noticed the power valve pin had fell out. My power valve was not working at all and it acted exactly like how you are describing your bike. I fixed it and it's like a completely different bike now!
 
Make your life easier and give Wayne Farmer a call at WOA Centurion, he will most likely be able to tell you what jetting you should start with and then take it from there.

where are you based?
 
ok cool.

I will open up the right side to have a look at the power valve.

As for running, its just really weak on power. It is pulling like a 85 cc, if that:eek:

Will have a look at the power valve, clean it out and get back to you guys soon.

Thanks
 
I have given Wayne a call. Called him at his Randburg branch. Said i should bring the bike in. Its a bit of a shlep as i live in the southern suburbs of JHB. he thinks it sounds like a power valve also.

Will get back to you guys.
 
OK. Carb is fixed. Got the float set etc.. bike is running. no leaks. Still haven't got the power it should though. The bike now sounds like it has a misfire, my guess is a fouled Plug??? Gonna get a new one on Monday when the shops are open. Any ideas which plug to get? And brand that is better than the others?:cool:
 
i have had the pv actuator bolt come loose (on the pv 'spindle'), and had similar terrible power output.

ngk plug. b8es, br8es, br8eg, br8eix. - run br8es until you are sure jetting is right. then you can swap to the more expensive br8eg or br8eix if you like.
 
jarrodw said:
OK. Carb is fixed. Got the float set etc.. bike is running. no leaks. Still haven't got the power it should though. The bike now sounds like it has a misfire, my guess is a fouled Plug??? Gonna get a new one on Monday when the shops are open. Any ideas which plug to get? And brand that is better than the others?:cool:
Click to expand...

Check the powervalve!

Mine stuck wide open a few days ago and I assure you it makes the 300 feel like a 85. Pull the pipe and look in the exhaust port.
 
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