| Author | Message | ||
     Carbonlightning |
Was curious if i had some minor head work done, i.e. port and polish with new valves and springs. Would i need new cams, pushrods, or lifters as well? Also what type of HP/ TQ increase would i be looking at? | ||
| Skntpig |
You would likely gain a few horsepower at the top and loose torque and power in the midrange. I shrink ported my intake side and d ported the exhaust on my stock motor and now it pulls like a tractor(added material instead of traditional porting). You can polish the exhaust side but I would do an brushed or unfinish the intake so you atomize fuel better. Bigger isn't always better unless you're going for a dyno queen or dragster. http://www.mototuneusa.com/think_fast_intake_porti ng.htm | ||
| Phelan |
While that is true, there is a lot of variables to consider when applying this knowledge to our bikes. The main thing is that the bike mentioned in your link has 4-valve heads. 4-valve heads have much more valve surface area and flow much more air in the lower RPMs than 2- valve heads. If the cylinder fills too quickly it creates turbulence and looses power, which is why bigger ports are not always the answer. However, a 2-valve head already has very small ports in comparison, so it's not necessarily a bad idea to port them, as long as it's done right. | ||
| Carbonlightning |
Cool, thanks because after this riding season i was thinking of getting my heads ported and polished and new valves and springs put in. I keep hearing thqat headwork is really where horsepower is made and gained. | ||
| Skntpig |
http://www.jetroadracing.com/racing_pages/pop_ups/ ports.html http://www.jetroadracing.com/racing_pages/service/ buell_engine_service.html It works on these buell racebikes... I did this in my garage and it works. Of course I wasn't able to shrink the intake in the same shape as they did but I did raise the port floor quite a bit and straighten the flow. I have a stump puller now and it is so responsive I'm scared to let people ride it. It's really explosive acceleration. |
