What to do with 2006 yz250

[quickstang77]

Tired of my buddies who rag on me for buying 2 strokes who all ride 450's. We are all B class to A class riders. Just looking to be even with these guys. Love the light weight and handling of the bike just want alittle more. I read about the 265 kit for 500$. Or do you reccomend the 310 kit? I see max power engines offers stage 1 2 and 3 do u? Any info greatly appreciated. Thanx

 

[Eric Gorr]

That engine is geometricly limited on stroke because of the piston length to port size. Its also thin. You'll get the best power with a 265 because the porting is so much more effective than loading the connecting rod with a heavy piston.

 

[brentl]

Eric, could I ask you ( respectfully ) why and how your porting works better ( which I'm sure it must based on your customer's comments ) than Yamaha's when it is touted as refined for years and being balanced and linear , etc. , etc . superlatives and so on ?

What is it that Yamaha isn't doing or can't learn? Is it hand finishing ? Are they really leaving it too mild for the average Joe ? I find this really intriguing ....thanks for any of this you can explain to me !

 

[Eric Gorr]

All YZ125 and 250 cylinders are hand-finished at the port heights, and Yamaha is the only manufacturer that does this. I built a YZ275 for Canadian Dave (moderator of the KDX forum). We narrowed and re-angled the rear transfer ports so it pulls cleaner at a lower rpm. Also I turned-down the cylinder base .5mm to retard the ports. Dave added a 16 ounce flywheel weight.
The stock engine is great on a moto track but a little clumbsy on tight tracks with off-cambers or the woods. We basically detune it to make it more ridable.

 

[brentl]

Ah... that helps me understand .That sounds like some impressive low end mods. Thanks
For moto work, your mo betta would still be better than stock though ? ( Mostly this is what I was wondering )

 

[quickstang77]

Eric I am located right around the corner from PR2 racing. I was talking to them about some options and said that they reccomend stroking the bike and it would become a 263 I believe is what he told me. They had an 06 there that they just did this to with a procircuit pipe and silencer and vforce 3 and dynoed it at 58 horses. Is this good? What are the downsides of stroking.