2010年8月30日 · The 290 was the best of both worlds. It allows you to be a little less on the ball as far as being in the right gear all the time because of the additional cc giving it a midsize four-stroke feel.

2013年7月10日 · most likely rich if the pilot is stock. A 290 will create more vacuum when the throttle is closed, thus pulling in too much fuel from the stock pilot. Is jetting still stock? Have you tried adjusting the pilot screw? Maybe try searching the jetting database for similar big bore kits.

2007年7月22日 · My Dad's friend and old pro Denny Swartz has a 290 kit (not sure what brand) in his 04 yz250f and loves it! In fact, he actually sold his 2011 crf450 because he preferred riding the old 290f over it. I'm pretty sure its been solid as a rock, …

2019年10月1日 · I was just wondering what some peoples opinions are on the Athena 290 big bore on a wr or yz250f. Will I notice a difference in power? Is it worth the money? Is it hard on the engine?

2011年3月2日 · This bike has it all pretty much, down low tractor ability for hill climbs, plus it doesnt take much to unleash the beast, awesome power out of the turns (tight or wide open). Once I figure out the jetting and put a 48 or a 15 tooth sprocket on, the bike will be awesome!

Choice between 83mm Forged JE piston kit or 13:1 Wiseco piston kit (Stroker compatible 310cc) (add $50) , Cometic big bore top-end gasket set. We install a stainless steel Crush ring in the cylinder to ensure the head gasket seals properly. ($50)

Buy Yamaha GYT-0SS56-31-12 Athena 290cc Big Bore Kit for Yamaha YZ250F: Rebuild Kits - Amazon.com FREE DELIVERY possible on eligible purchases

Athena’s Big Bore Cylinder Kits guarantees an increase in performance that can be observed along the power curve, keeping the reliability at the same level of the original components. The kit includes the high-quality aluminum cylinder with increased bore, the complete piston with the piston pin and rings, and all the necessary gaskets.

2007年8月16日 · Generally how many sizes in the main jet have you 290 kit owners out there gone down from when you had the bike stock? I tried looking for a comparison in the jetting stick with no corrolation. WR290F 2006: 165 Main. Stock Pilot Jet. Fuel screw (turns out): 1 3/4. JD red needle 4th pos (may try 3ird) Airbox snorkel off. stock pipe.