missouritrailrider said:
anybody ever ported and polished their own head? i did mine with a light porting to clean up casting marks and polished the exhaust port, it seems like it should help out good, i also had a local shop perform a 5-Angle valve job on their serti machine
I do all port work on my bikes, I've had quite a bit of training and practice though, as well as a flow bench.
Technically speaking, cleaning up casting marks isnt porting... its "cleaning up casting marks"
It can help a little in general effeciency, but it usually wont even show up on the dyno because its well within the margin of error (run to run).
Theres a lot involved in porting properly, a flow bench is a must. Unless you have training, or know some one that can physically show you (to teach you), the simplest blends or extrusions can be disastrous for flow.
As for valve jobs, 5-angle vs. 3-angle, completely depends on the application. As far as sealing properties, there is absolutely zero difference, none, nada!
As far as flow, it depends entirely on the application. A lot of places will claim it always improves flow, and thats total BULL. In some engines, a 5-angle can produce a better flow characteristics, but theres a lot of variables involved (valve type, valve location, chamber shape, even the shape of the valve stem!). In many engines, it wont make a damn bit of difference.
I hate to say this, but its hard to rely on "data" from shops that offer both 3 and 5, and charge more for the 5. So theyre motivated to tell you 5 is better no matter the application.
A good engine builder, who
does not "sell" his own valve-cutting, usually is more reliable. They dont like to waste money if it does nothing, but have built enough of that engine to know what shows up on the dyno.
Generally, I wouldnt bother with a 5-angle on the Warrior/Raptor, theres no performance difference on the 350 engine compared to a 3-angle. If theres no difference in price at that shop, then just go for the 5 (some shops only offer 5-angle anyways), it wont hurt anything, and it'll still work fantastic.
