Porting can be one of the best performance mods you do to your bike; especially if it’s a 2-stroke. It can also be the demise of it if not done correctly. You see, the bike factories build the engines to certain specs so that it has the best overall and usable power. So by changing the port timing and dimensions alone, you’re not going to see a huge gain in performance, and possibly a loss. If done right, you will merely be changing the power-curve or peak horsepower, depending on what you’re looking to achieve.
Easier Said Than Done
Porting itself is not a difficult task, but it takes a lot of knowledge and patience to port an engine and produce more power, which is why professionals can charge a few hundred bucks for a simple port-job. If you don’t have experience or training, I highly suggest you send it out to a professional engine builder. Most of them know what they’re doing, and all you have to do is tell them what you want more of (horsepower/torque) and where, what fuel you’re going to use, and they’ll take care of everything else.
Bigger Is Not Always Better…
Any skilled engine builder you ask will tell you that bigger ports alone aren’t going to produce more power. In fact, more often than not, it will reduce power. Like I mentioned before, there’s a reason why the factory made their engine a certain way; to produce the most power over the broadest RPM range. So if you grind off just 0.5mm (.020″) from any of the ports in the wrong direction or location, it will lose power somewhere and gain little to no power elsewhere. Porting is an art; not a job for a hacking grease-monkey.
Bring It To The Best
There are many good bike tuners across the States, so do a little research to find who’s close, in your price-range, or if they can get the job done the way you want it. Eric Gorr (Forward Motion), HPBikes, Pro Circuit, and Max Power are a few that come to mind if you want quality. Generally, the more you pay, the better job will be. But, make some calls to these guys and see what they say. Most of the really good builders are easy to talk to and will get it done right, and fast.
On the flip-side, those of you that are mechanical and willing to do some modifications to your engine (with a risk of ruining it), I will make another article in the future on how to get the most of it while keeping it stock. This is done by blueprinting…