porting
ok, ncyz250 guy, I would have to say you are on the right track when you say motor pulls from low end into high better/farther, that is if such porting exists by forward motion. If it exists, I would get it-give it a try. Porting would increase top speed and acceleration, I believe, but top speed can be most noticably affected I would say.
but I am under the impression that you really can not have the best of both worlds.. Like timing, if you advance it you gain lowend but lose topend, if you retard it you gaintopend but lose lowend...if you increase one you will be ultaimately sacraficing the other. If you had a 125 I would say increase the cc's. If you had a 500 (2cycle), I would say port and polish it for low end and use an exhaust system to match (lowend). Well a 250 is the happy medium, so I dont know for sure. Um, I guess I would personally go for as much low end as possible, within reason, there as well in order to make the bike more ridable, tractable and controllable since I am not very skilled of a rider (or not a racer) even though I have been riding (ATC250r350x/ Banshee/ enduros xl/r350, dt125, f9 350, CM400T, xp800, Vmax600, srx700, sxr700, tx340 440/ etc.. ) various bikes for nearly 20 years. Make the bike more like the trend...trench digging 4-strokes! I ride a cr500 with 600cc kit and I am finding the need for more low end power, but there is a key reason most likely exclusive to me and that is I ride on road. When I ride on the road I do not want to over rev my engine (I dont want to wear it out too fast). 5000rpm is plenty for a cr600 to move you down the road and you dont have to redo the topend every 2yrs. If it doest blow more like should last 6 years at least. I have/had a '85ytz250 still on the original topend. When the topend wears (and it will wear out faster when used high reving) it won't run well in hotter weather (or slower riding) because the piston superheats I think. But for offroad (and/or racing)its a whole different ball game. When I did ride a 79rm125 offroad and the throttle stuk wide open I had a very hard time controlling the rear end. I dont like that high reving power too much, but a little is great and that is why I ride a 2cycle on road besides the fact that I do my own engine work and I dont like to work on four stroke engines. Just my personal opnion.