07 EC300 power band question.

[Hugh Jarse]

Hi folks. Firstly, new here so hello

I've had my EC300 for about a year now and done plenty of hours on it but one thing - the power band... I never get a 'hit'. The power delivery is quite smooth and never seems to give me that explosive power that you would expect from a 2 stroke.

Does the ec300 have a hit, or does the power valve work to make the low down power enough not to notice a rush of power?

I have noticed my power valve is full of carbon so will be taking that out soon to clean it up. Will take a look at my piston and rings while I'm at it.

Mainly I wanted to know, do other owners of the bike get a hit when it enters the power band or does my "issue" sound quite normal?

Thanks in advance.

 

[Zman]

First thing I would do is open the PV side cover and rev the engine to make sure the PV is actually opening. Sometimes the stud on the actuation plate on the kickstart side breaks free and the shaft goes up and down but the PV does not move.

 

[(F5)]

Read the jetting threads. Needle can affect how the power feels.
But the large low down power fills in the curve so there is less step than a small cc bike.
Sure feels like a grunty 2stroke in the dirt. On wide open areas will be less pronounced. Buy a 250 MX bike if you want more excitement/less control.

 

[Hugh Jarse]

Read the jetting threads. Needle can affect how the power feels.
But the large low down power fills in the curve so there is less step than a small cc bike.
Sure feels like a grunty 2stroke in the dirt. On wide open areas will be less pronounced. Buy a 250 MX bike if you want more excitement/less control.

This is what I was thinking... The large displacement cc evening out the power curve. Didn't know if it was supposed to have a hit like the lower CCs though.

Zman - it is working at least partially. I know this because last weekend the PV came loose and I had to get in there and tighten it all up. Power returned "as normal". But I'm thinking the carbon build up could at least be stopping it opening fully due to thwre being no hit in the Power band and as mentioned, power is quite gradual and smooth (as smooth as a 2 stroke can be anyway I guess!).

Didnt want to get in there with jetting just yet because lean or rich would both make the engine run crappy and not sure which it would be... Is not revving out common for running rich or lean? Should one be raising or lowering the needle...

I'll check out the jetting threads for sure.

 

[motopsycho87]

Record a video of you giving it everything through the gears. These bikes definitely have hit, not as much as a 250, but they still have the peak power of a 250.

There are so many contributing factors to this, but after all the maintenance items (reeds, rings, air filter etc...) Are done, it comes down to jetting.

 

[Mudshark]

You can make the 300 hit hard enogh to kill you if that's what you like. A little porting and timing adjustment along with a small carb mod and a more agressive cdi. I had one like that and sold it! LOL

 

[poelinca]

https://www.youtube.com/watch?v=hmz9cij6MVY Best video explaining how it works. There are numerous posts on the forum that explain how to set up the play.

p.s. while you are at it, make sure there aren't any extra spacers in the governor ... look at the parts diagram

 

[husley]

Maybe the previous owner did what I did to my 300:

Put a thinner base gasket to move the powerband down low. After I did this I had nearly zero top-end hit. LOTS of grunt, but almost no hit, a very linear increase from mid-high.

Good luck