GasGas UK's suggestions for more low end


New member
Me and another chap who may be working on my EC200 have just had 2 separate conversations with 2 different people at Gasgas UK regarding getting more bottom end power.

Both conversations went along the lines of "don't bother with flywheel weights and volume powervalves, just thin the bottom gasket first, as it is easier than doing the squish and has decent impact. Then do the squish if you still need more."

I was hoping to get a powervalve spacer or flywheel weight and just bolt on but he said I'd just slow the bike down. Most people seem to report some grunt for a weight. Confused. Maybe I should just buy them and see.
You do not slow the bike down, because in high rpm the PV is open and the increased chamber has no effect.
I would try the spacer ;) and next a thinner gasket. As fare as I know there is also a FMF Gnarly available for the 200cc
Smooth is good for me. I though, with him working for gasgas, he might be a good rider and want an aggressive setup.
I may be able to help here. I own 2 EC200's. Ones a '99 and the other is a '03. They both have the exact same setup with fresh topends, LT power valve cover and same jetting. Same tires, etc. The only difference between the 2 bikes is that the '99 has an FMF Gnarly and the '03 has a FMF Fatty.

I rode them both back to back yesterday on the same singletrack trail. The difference in the power delivery is quite significant.

The '99 with the Gnarly pulls immediately off the bottom. It will loft the front end at lower rpms easily. It pulls hard to mid and then settles down and signs off as you get to the top.

The '03 with the Fatty is much softer on the bottom. It is smooth on the bottom but doesn't have the pull. But, it comes on strong after 1/4 throttle and is nice and strong at the middle. It keeps pulling very well all the way to the top.

Both bikes are effective in the singletrack. For me, coming off of 250's and 300's I like the pull right off the bottom but am getting used to riding more at mid throttle where the '03, which is mine, likes to be ridden. The '99 is my sons and he is good at riding a gear high, plus he likes wheeling:D
Easy to change the gearing, and easy to change back.

Fly wheel weight adds rotational mass and slows the response down. You could try running a bit heavy rear wheel some time as it'll do similar. I see it as an option to smooth things out and perhaps become more tractable, not more power.

Port timing (via base gaskets) has a noticable effect on the power curve the engine makes. When it comes into its band, and when it signs off. Altering it also alters the squish clearance and compression ratio so be aware of the other variables.

Increasing compression also adds to the bottom end snap, but can rob from the top end and if taken too far will result in poor running and the requirement for excess fuel to keep it cool.

Squish clearance should be set once determining the port timing. A tuner will then machine the clearance, angle, and adjust the volume of the combustion chamber to meet the desired compression ratio. Gives a boost across the board and results in more efficient running, better fuel economy, and more stable jetting.

I agree with Gas Gas advice, but I'd do the head straight up too. I stand by this so much it was the first thing I did on my 2013 model. I've learnt not to waste time chasing circles until tolerances are within the desired range.
On my 02 200 I fit the PV spacer which I made but never properly tested before and after.

No question 1 base gasket (std had 2) and re shaping the head and raising the comp is best option.

I love few weight on my 300 but 200 EC didn't need it
I'm running an '06 EC200. I use it for riding in sportsman / novice class and occasional greenlaning. Going to the single base gasket made a big change to how the bike runs, although I would echo Jakobi's advice about getting the tolerances and port timing right if you would like a 100% job. Just doing the base gasket was good enough for my purposes, although I might go to town on it one day. Fuel efficiency is about 80 miles to a tank and power delivery is spot-on for me, plenty there when you need it and doesn't punish small throttle control errors like the EC300 did.

The UK EC200 nearly always have 2k3 (believe other regions get the 2k2), so already have the bigger flywheel. I wouldn't personally bother with the powervalve cover, just freshen up the engine, build it up with one base gasket and go from there.
Proper jetting is the fisrt stop.

If you are going to mess around with gaskets, just get the bloody head done, it's cheap, any body with a lathe can do it, just make sure you adjust the compression ratio too. There are numerous posts telling you how to do this, or if you really need, ask me and I'll make a guide.