HD Performance 101

We all love to get as much performance as possible out of our motorcycles and owning a Harley Davdidson makes you no exception to this fact. Once you pop you cant stop is the general incentive granted that there are some riders who are comfortable at the level of performance a standard Harley provides and this is totally ok. Having owned a couple of different Harleys throughout the years Ive always been one to look further down the rabbit hole and tried to extract the most that I could in terms of performance.

This would bring us to the a point where we would need to go and look into what we could find in terms of performance parts for our Harley here in South Africa and at the time we were fairly limited in choice. Dealers wanted huge sums of money and the waiting periods were excessive and to import directly from overseas seemed like a huge task at hand.

Fortunatly times have changed and our company Roxstar Performance is in fact an expert now in bringing or importing Harley Davidson Performance parts. Whats more is that we are able to advise you what we would recommend for your specific Harley model whether it be a Sportster, Softail, Dyna or Cruiser it doesnt matter we have developed a range of products that was carefully selected from our suppliers whom we chose with due consideration as we only wanted to supply the absolute best in terms of quality performance parts for your Harley Davidson motorcycle. I have decided to break this article down into 4 different so called sections which will basically outline a 4 step process one can choose to follow when upgrading the performance and looking for the correct parts to do so.



s&S cycle performance harley davidson parts

Step 1 – Performance Exhaust and air Cleaner

The first step is probably the most cost effective and their are some great options out there to satisfy this requirement. A new performance exhaust combined with an air cleaner to help your bike breathe better is gonna add some cool, crisp performance and also some seriously cool style and weight savings. This is definitely the most popular step in  the performance seeking game and alot of riders opt for this initial step as it really does uncork the bike and you get a better looking and sounding bike at the same time. For more on Aftermarket Harley Davidson Exhausts why not check out our article on Harley Davidson Exhausts. Stage 1 is therefore a more common phase that falls inline with what the average rider looking for extra hp on a bit of budget would do and we highly recommend all riders go for a stage 1 upgrade. Our brands that provide great packages for stage 1 upgrades include Vance and Hines, Bassani Exhausts, Cobra USA, Rhinehart Racing, Tab performance exhausts, S&S Cycle and Samson Exhausts. All these brands and their associated products can be purchased through Roxstar.


custom motorcycle design

Step 2 – Get even more horsepower!

Ok so having gotten past step 1 you may be totally satisfied but the next 3 steps are for the serious horsepwer seekers – Those who are really looking to blow the competition away in terms of sheer performance in both horsepower and torque.

For the purposes of this article I am gonna make mention of one of our suppliers – S&S Cycle from the USA make performance parts for Harley Davidson Motorcycles and we are a supplier for their products down here in South Africa – Quaity parts if perforformance is your thing then these guys have most definetly got the parts to get you there.  Alot of the brands mentioned above focus mainly on stage 1 parts supply and the reason for this is that most riders dont venture past the first stage. Really going beyond the first stage does kind of hurl you into a more niche market where you need to be carefull regarding what you are doing as ineffective parts due to poor quality or unsound advice can blow your engine in some kind of nasty way. For the following 3 stages we highly recommend S&S Cycle.

Once youve let your engine breathe a little bit and slapped on an aftermarket performance exhaust its time to go to the next step. Step 2 is gonna be to replace your stock camshaft with a bolt in performance cam. Dont let this scare you as S&S Cycle have got you covered here. Their bolt in cams make it easy to gain some serious hp and torque which is exactly what we are looking for. Fortunatly they offer a complete line of bolt in cams for most model Harley Davidson Motorcycles. Furthermore you can choose from stock chain drive style, or upgrade to S&S gear drive cams for the ultimate in valve control.

S&S highly recommends S&S Easy cams, which feature centrifugally operated compression releases that are not only convenient, automatic, and foolproof, but also have the added benefit of reducing wear and tear on your battery and starter.

Upgrading your cams requires pushrod removal. S&S recommends installing S&S Quickee pushrods. They are fully adjustable, and allow for quick removal for other future upgrades or tappet replacement – they pay for themselves by saving time on labor.

So there you have ot for stage 2 – You will really be feeling the difference after you come this far trust me 99 percent of the Harley wont be able to match your performance at this stage of the game. Keep reading for a look into what S&S offers for stage 3 and 4 simply mindblowing in terms of how far they are able to stretch the power increase capability of your Harley Davidson.


power-package-kit harley davidson performance parts

Step 3: S&S Big Bore Kits

Now we are onto stage 3 and things start to get a little more complex but luckily with S&S parts its all so easy and simple compared to scratching around some backyard supplier and trying to best determine what would work for you – This 4 stage process has been tried and trusted by the masters themselves and should serve as a good guide for anyone who is in the game of increasing horsepower to the absolute maximum.

Lets us at stage 3 introduce the big bore kit which is an easy way to achieve more displacement and if you can apparantly install it without rebalancing fkywheels or the crankcases, then its pretty easy apparantly. The idea is not to have to bore or even split the cases, just to do the cylinder and piston swap  – Thats the idea behind the S&S big bore kits for Milwaukee eight and Big Twins engines.

According to S&S the performance kits do provide excellent results with stock cyclynder heads, but a performance cam is recommended in order to get the maximum results and best performance. Further they recommend the easy start cams with built-in compression releases to make the engines easier to turn over at start up. S&S cylinder heads with increased head flow and resulting power increase are highly recommended for the absolute best in terms of performance.

So thats a wrap on stage 3 – At this point you are now probably the fastest on the road in terms of Harley Davidsons with some serious reliable hp and some neck braking pull away speeds from any traffic light enjoy – Enjoy the thrill and feeling its certainly well above where a standard Harley Davidson would be. Lets move onto our 4 and final recommended stage.

big bore kit 1
big bore kit 2

Step 4:  CNC ported cylinder heads and fuel filter upgrades

Right we are onto our 4th and final stage regarding attaining the absolute maximum in terms of performance for your V Twin Motorcycle using the S&S Cycles tried and trusted methodology.

At step 4 the claim is pretty mega and yes S&S claim that by step 4 you can excpect to gain some 40 hp over the stock setup. Thats simply an insane amount of extra hp your bike will be basically a rocketship and reliable at the same time! Step 4 is for the serious performance enthusiast and most riders will have been more than satisfied by the previous steps but then again you always get the 1 percenters or the guys who simply have to have the maximum and we understand totally thats exactly why step 4 exists – Its the step the will differentiate yourself to the absolute maxmimum degree and provide you with one of the fastest in class Halrey Davidsons in the world.

Upgrade Your Heads with CNC Porting

Send your stock heads to S&S and we’ll use our state of the art CNC machining centers to reshape both intake and exhaust ports, as well as the combustion chamber. The goal is to maximize air flow while maintaining port velocity.

System Upgrades

Don’t let your stock carb or EFI throttle body limit your horsepower! Give your CNC ported heads all the air they want with an S&S performance carburetor or throttle body. Carburetors depend on air velocity to deliver fuel, so while you want something bigger, too large a carb will hurt low rpm response. We generally recommend the 17/8″ S&S Super E Carb for 97″ engines. However, on the drag strip, the 21/16″ S&S Super G carb will deliver the best top end horsepower. Since electronic fuel injection systems use a high-pressure fuel pump and a computer to deliver fuel, velocity in the throttle body is not as critical. A larger throttle body will not degrade low rpm performance, so S&S recommends a 58mm throttle body for both 97″ and 106″ engines.

harley davidson performance parts cnc heads


Thanks for taking the time to read this far. We totally think that stage 1 is the best value for money and is a must for nearly all riders but the additional 3 stages are for the guys and girls looking for the extra bit of excitement from the performance of their bikes. Some may call it overkill and to others it would seem like a totally natural and prgressive upgrade package. We will let you be the judge of that but 40 additional hp is pretty insane if you ask me that like night and day. Please note Roxstar Performance is a registered dealer for all brands that have been listed in this article but please do check out the S&S Cycle official website for further information on the brand and all their exciting products that they offer. The above serves merely as a guide in directing you based on one of our premium suppliers advice its not necessarily the be all and end all and we are sure their are other methods that work just great to – The above is just a process we feel has a tried and trusted reputation and the parts come from an equally reputable international brand.

Also check out our post on what would be considered a stage 1 kit – Performance Harley Davidson exhausts and air cleaners