[david]

can it be done by yourself with a dremel and some polish or something?? i know you can do it like that on holly carbs and manifolds and such. i run a stock head, cylinder, carb, and just want a more power behind it, i hear that you can do this, and the valve size has to remain the same on the stock head (it cant get any bigger if ya look at it).

 

[BlackBall]

I would not advise trying to port your own head. Places that do it machine them out and have flow-benches. If you have some dremel skills, you can go in and clean up some rough edges etc, but I wouldnt try and full on port it yourself.

 

[flyin_frank]

actually you can get larger valves in there but anyway porting is a good idea butt not if you lack the skills to do it right i would say get a big bore kit first then port to match the bigger carb and manifold this stuff has really gotten cheap to pick up.do you have a pipe pr any mod yet?

 

[david]

yeah i have a pipe... fast50 pipe, and some other stuff... 40 tooth rear sprocket. choped and modded frame which has a old yam 125 trail bike shock on it, some other stuff. i only like racing the stock classes for now and i riiip around fairly well. i just want more out of the stock configuration. i only hear if you take out the choke and plug the hole you get a better airflow, not much but noticeable?

 

[xr50racer]

the stock head configuration is not going to yield you the room to go with bigger valves. you cant just plop them in.



As for porting most "performance" shops as they call themselves fdpnt even have flow benches to check their work. I hate when a shop is calling themselves performance and they just go in hog out the port and dont know what they are doing.



Id take it to someone knownw for doing port jobs on a 50 head. DONT POLISH YOUR PORTS

 

[XmutinymotorsportsX]

50racer is right. Most places these days dont own flow benches, and if they do they would charge ungodly amounts of $$$$$ to port your head. A real port job can take a few weeks if the person really knows what they are doing. (this mainly has to do with car heads but should cross over into the 50's) No one I know does polishing anymore as xr50racer stated. It can actually cause undesirable affects. The furthest I would go is to maybe clean up the intake and exhaust ports, port match them, but dont touch the combustion chamber. You can actually lower your compression and make the bike even slower. Reverse of what you were looking for. But honestly in my opinion, if you can afford to have someone else do this or buy an already ported head go that way. You might just save yourself the trouble .........

 

[BlackBall]

PRC ports the head as much as possible and uses flow benches to test. And I beleive it only costs $80 for an xr50 head.

 

[xr50racer]

is that just porting the stock head? does that include larger valves? which you will need. DOes that change your combustion chamber? alot of head jopbs change the combustion chamber utilizing a high dome piston to give way for clearence for valves that are larger. Im not thinking you will get that for 80 bucks.

 

[BlackBall]

Its for the stock head. I am not sure what they do exactly. I wouldnt think for $80 they put bigger valves in, I beleive they change the size and shape of the tunnels. I do not know much about porting I was just stating the price I had heard from someone.