Cylinder head port

[Darkkill57]

So I've been wanting to get into more engine work lately and get some more ponies out of the ole mule and I've been doing some look seein around when I saw talk of porting the cylinder heads, I've watched some videos and did some very light reading on the subject but I thought I'd come here and ask those that have done it or maybe had it done, how easy/hard is it to learn, will it be worth the effort and how much of a performance increase did you notice after doing so. I've already done the whole new exhaust intake and carb rejet so it looks like my next choices are on the engine side of things from what I can tell

[Lug Nut]

Dave J did his own porting on his heads with great results and then also sent them out for a full competitin race port by a VERY good head porter and gained a little more. If you know what you are doing it's worth it if your spending time and not $. But you can 100% easily screw up velocity, charge mix, size of port/runner and end up with a slower bike overall (even if it dyno's higher). I have a used set of 1600 heads (stock assembled) I was keeping for a future build to have ported but I now have new Speedstar CNC ported 1600 heads. I would sell my used heads pretty cheap if you wanted a set off the bike to mess around with? $150 shipped for the pair ..

[Darkkill57]

As much as I'd love to have a pair to dick around with and still have a ridable bike I don't have the funds to throw at spair heads sadly, did you have your heads ported and if so how's the before and after feal?

[Duke]

Head porting is a art, and takes a lot of time, tools and learning what works and what doesn't.
I started porting when my dad's friend introduced me to porting and gave me my first tungsten carbide cutting bit over 45 years ago. This was with my dirt bikes went I use to motorcross race and became a motor-head.
Since then I have done numerous engines, and when I use to race autos I built, ported, and tuned engines to pay for my racing, otherwise I wouldn't have been able to afford this expensive habit.
For a beginner, just remember that bigger and smoother isn't always better. One thing that has helped me, is to think of the port as "moving fluid". Some of my flow numbers have considerably increased by doing just a little in the pocket area behind the valve, smooth on the exhaust and ruff on the intake, transitioning to the port runner. A good 3 or 4 angle valve job is very helpful, but must be done with precision equipment.
Porting a stock engine will not give you a bunch of extra horse power until you do other mods, such as pistons and/or cams, but any gains is a positive in power. It all adds up.
Good luck with your endeavors.

[Darkkill57]

Thanks duke, any good articles or books that's gleam some more knowledge on the subject?

[Duke]

There is some HP books and literature that I have had on this subject. Most of my learning has been before the CNC machines. You will have to do some research finding what your wanting.

[davej]

I did a "cleanup" type port job and I had a noticeable improvement a better improvement than that of porting just the intake manifold. I knew that wasn't gonna be the end of my porting venture. I then sent my heads to Shortblock Charlie at Pro 1 Racing Heads in AZ. I had 2mm oversize valves installed when he did the hand porting job. Along with the Big Bore and other go fast mods that I installed the bike is a literal beast As Duke said, porting is an art and if you make a little mistake by not using a flow bench and other Equip you can end up with dead air spots that can actually decrease performance..

[Darkkill57]

Sorry for the lack of knowledge but what do you get outa bigger valves?

[Duke]

Bigger valves = more air flow. More air = more power.