Paulwhite Posted October 16, 2010 Posted October 16, 2010 hi just a quickie lol porting and polishing. is it just taking out any lumps and bumps left buy the casting of the cylinder head? and then polishing it all up so the air/fuel mix flows freely through the inlet port? and what gains would you expect from it in say a 125 engine?
Moderator Airhead Posted October 16, 2010 Moderator Posted October 16, 2010 Yes it is Paul and I doubt you will notice the difference.
wild foamy Posted October 16, 2010 Posted October 16, 2010 There is slightly more to it than that but in essence that is the general idea. i had some experiance port and polishing glow engines (used in model cars and aircraft) best left to the pros on bigger engines though, my first couple of glow engines didnt go quite right
Paulwhite Posted October 16, 2010 Author Posted October 16, 2010 ok just wondered cause iv attacked a cylinder head with a dremal today for a "practice run" type of thing and its not gone too bad (just took a shaving off) just took out most of the big lumps and bumps/sharp edges then used 600 grit wet/dry paper to smooth it out (took fookin ages), popped it back on the engine and its sounding a bit better, seems to be flowing nicer, and it wants to jump of the stand (didnt do that b4) nearly took my foot out!
Moderator Airhead Posted October 16, 2010 Moderator Posted October 16, 2010 ok then perhaps I am wrong, let us know how it is then.
HoughMade Posted October 16, 2010 Posted October 16, 2010 Believe it or not an intake tract can be too smooth. Some bumps and lumps are needed to aid mixing of the air and fuel. It may flow more (to an extent) but it can also move whatever power gain up the rpm scale and cause harm to the low end and midrange. Also, it has been found that some texture to the walls allows the creation of a boundary layer of the moving fuel/air mix that actually aids flow, as well as mixing. If it is polished too smooth, the fuel/air mixture can actually adhere to the wall (like water clinging to the wall of a glass) rather than moving through. ...Good luck!
Paulwhite Posted October 17, 2010 Author Posted October 17, 2010 yeah i read about that but it said if its a mirror finish then it will stick and slow down flow and to be honest mine is far from mirror finish lol iv only done it so its smooth to the touch but i could always get some 160 gritt wet/dry on it to rough it back up again if i need to. im just tinkering and havin a play as ya do and id love to be able to tell you what speed gains/losses if any had come out of it but its not in the frame yet ..... still need to get some mounts made plus il be tinkering even more with it b4 it goes in, like sprocket size, arrow performance exhaust, k+n air filter, possibly a 150 big bore kit later on (if i can raise the funds) a little hot rod trick with the spark plug (face it towards the exhaust port). but it seems to rev that little faster and the exhaust note has changed (deeper) so initial thoughts are that its helped but wont know for sure till iv tested it on the road, its a honda cbr 125 (2004) engine with 5k miles on it and the average is about 80-85 mph standard (according to the speedo) so with the mods iv made it should hit at least 80mph considering the dragstar frame has more weight to it. the engines are almost the same spec wise but the cbr has more torque and is lighter which should help pull the drag frame better il have to weigh it when its done and do some calculations.
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