larger intake valve

One of my mechanical bike guru buddies...suggested I put a larger intake valve in while they heads are off getting ported and polished.
I understand the concept, the stock cam will stay be able to pull more of the air into the cylinders.Larger valves for very little bucks(from CD). can help. Any suggestions,input or things to consider. This will keep the enhancement to a minimum but should actually allow the stock to work easier and get a little more out of the setup without big boring or other setups. This is always so much easier for me when it is car related.( Pappa owns an automotive machine shop with all the latest toys....plus we drag race and build street cars for fun.)
The bike is not intimidating just not as familiar with all that has been done by others.I've done other things to bikes over the years but not really wanting to get into increasing the "performance" too much and lose reliability and gain wear on parts.Plus I am trying to leave it sleeper-like.( Actually thought about the NOS system) got a buddy out here that did the whole shib-bang this year, gears,boring,heads......because last year he could not get around me .
One pop of the button and woosh he'll wonder what got him again . First I gotta find a place to hide the system if I get it. But the heads are in process.
It'll still sound stock lobed but pull more(it should anyways)

Bad idea...Big valves with small lift cams will slow port velocity and you actually get less cylinder fill.

Here is a great rundown by a shop with proven results.

http://www.bigboyzcycles.com/harleyheadporting.htm

I agree with the hag. Bad idea. You will definately have a problem with cylinder filling and thus see a drastic reduction in torque on the lower end. At high RPM's you may see a little of the velosity come back due to the increase in piston speed but with stock cams it wont make much of a difference.

A note on head prorting. Be careful. If you open the intake port any more than about 85% of the curtain area on a Harley head you have problems. Harleys have short small diameter runners and thus benifit from a slighty smaller intake valves to make the package work.

One word:

Velocity...Performance heads are never all about CFM by itself. A good head will have a balance of CFM and velocity.

You hear about it all the time at the Hot Rod shops. Guy buys big valve, high flow heads and already has a small torque camshaft thinking it will work on the street. Won't listen to the guys behind the counter, buys what he wants and then blames the heads.

A head can have a ton of flow but, without velocity, it is just a lump of aluminum.

BTW, if you are not ready to pop for a set of reworked heads or have no intention of going with a Hi-Performance setup i.e. big cam, cubes etc, I would recommend do some minor polishing, unshroud the valves, clean up the bowls etc.

thank ya

I did ask the "guru about the velocity flow and did not here what I am hearing hear. gotta have that..sounds like the cam is perfect for the stock enigine..that is what I am doing mow..the polishing and all is getting done in the shop here....that'll help enough for me....the valve was one of the bike "guru's" reccomendation. I think he's a bit out of touch with the newer stuff. I did however double think about an Andrews...I love this stuff!!!
If it were a Chevrolet,Ford, etc I'd be right at home with what works good. Bikes engines performance are (same concept) just not my in my backround.
Glad to know there are those of you willing to share the insightfullness of their expertiese...thanks all!!!