gg250f loss of power question
 

OK here is the deal

I have a 2011 GasGas 250f which is an enduro with a 2006 wr250f motor. It doesn't have a grey wire or the other restriction stuff. I bought it used and seemed to be low on power. I put an 06yz250f piston in and no change, and the old one was fine, put in yz exhaust cam very little change. Megabomb header and 4.1 slipon and NOTHING like my other bikes.

I have a 2006 yz250f with a flywheel weight which is a beast. I have a 2013 yz250f which is also a beast. Both are stock minus an exhaust on the 2006 but the 2013 is completely stock.

Any ideas where to look. It does ok on level ground but under a load like a hill it shows its lack of power. Air filter is clean, oil is new. I am at an absolute loss. IF I could get electric start and power similiar to my 06 yzf this might be the best bike ever made by man so please help.

Ignition timing/CDI? Head?

What would I check on the CDI or head?

Head - Valve clearances/sealing
CDI - No idea how you'd check it short of swapping it for another. Is it the same as the ones on the Yamahas? Maybe..

Have you done a leak down test on it at any point?

Is it possible that the engines making power but not getting it to the wheels? ie slipping clutch/heavy rear tyre & chain/flywheel mass?

Whats the tune like? Are you running the same needle/jet combo across all 3 bikes?

Had the valves shimmed up with the new piston. Haven't done a leak down check though. I don't have any clue on the jetting mostly because there is a quick shot on there and don't know much about them.

I would assume it is a wr cdi but I don't know that. Will have to check before I try. It would be nice to put a yz250f one in but I am sure I am not that lucky.

Good stuff. I have to unload today from my 4 day Missouri trip and hopefully start later today.

Any chance you can swap the carbs over?

That is a great idea.

I will just take the throttle and everything and shouldn't be THAT hard.

that is a great idea... wonder if the gg wr needs the throttle stop thing done ? swapping carbs would tell you for sure..

http://thumperfaq.com/throttle.htm

He states it doesn't have any restrictions on it. It would be easy to tell if there is a throttle limiter on the GG's engine just by looking at the throttle cable at the carb, or peering into the back of the carb to watch the slide open.

My thought is to check the airbox on the GG. Is it restricting airflow some way when compared to the the YZ box? I would have said the silencer but you changed that. My experience with WR250's is that the stock silencer cuts down on top end power. That got me thinking what else is cutting off airflow. I'd try running it without it's seat and/or comparing the jet size between your '06 Yamaha and the GG.

It certainly looks like I need to drop the subframe to get it out. The shock at very least. Am I seeing this correctly?