Best Engine Mods for the Sportster: Part 2
Daily Slideshow: We recently published part 1 of the best engine mods for the Sportster. If that batch of enhancements doesn't quite satisfy your needs, these more intricate, and more expensive mods should do the trick.
Introduction
Waking up a Sportster is easy initially, as you just have to overcome the neutered state the EPA requires them to leave the factory in. So pipes and an air cleaner will give you an effective boost. Once that thrill wears off, you can change the camshafts but after that it gets expensive as major engine modifications (often irreversible) will need to be done and reliability may suffer; although, it is your bike and your money, so read on and see where your budget and skill level can take you. So if you're up for it, here is the second wave of upgrades to make your Sportster go even faster.
Part 2 Begins
DIY Cost – $600-$2,500
Professional Cost – $1,200-$3,200
Skill Level – Moderate; you will need the manual and possibly some specialized tools, or the ability to make them.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Camshafts
Simply put, camshafts change how deeply the engine breathes. Big breaths mean more air is burnt and that gives you more power; they also change when the bike breathes. For this level of upgrade, you should stick to a "bolt-in" camshaft; that means it can be fitted with no other mechanical modifications to the engine internals, but will still give you a radical increase in power.
Fitting camshafts in a Sportster requires the cylinder heads to be removed in order to take the spring pressure that the valve gear exerts on the camshafts off the camshafts, so you can remove the stock ones and refit the new ones.
Paying attention to the timing marks and cylinder head torque procedures is vital here. If you don't know what that means, then don't attempt the job yourself or buy the manual and read it thoroughly before deciding to attempt the job.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Cylinder Heads
While the heads are off during this upgrade, you can send them off to have them modified to increase gas flow through the inlet and exhaust ports, or to have them skimmed to increase compression and "squish" (how hard the gasses are compressed prior to ignition). These sort of modifications will increase the gains that the camshafts will give you.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Clutch
At this stage in the proceedings, the clutch (especially true of EFI models) will need a heavy duty spring added. These can be obtained from Barnett or Screamin' Eagle ($28 DIY or $150 fitted) and will need a special tool made, bought or borrowed to do the job.
This level of upgrade may move the power band up the rev range, but you will still have more grunt in the low to mid-range and this is a general characteristic of bolt-in camshafts. They give a reasonably even spread of power and more of everything, mostly right where you want it.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Ignition Module
You can add an aftermarket module or aftermarket ignition system to give it a higher rev limit (not recommended), or a different ignition advance curve to keep the engine from pinging or running hot ($225 DIY or $400 fitted).
You will now be very happy with your Sportster's performance but a bit lighter in the wallet. what comes next is seriously expensive, so maybe leave this article now.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Going Ever Further
OK, so you're still here? This means you are committed to getting every last horsepower out of your Sportster. It isn't easy and it isn't cheap! It requires a lot more time, effort, and money. But sometimes, the wallet will have to pay for what the heart desires.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Expert-Level Mods
What we are looking at here is extreme everything. I'm talking about some seriously hot camshafts that are designed to give huge amounts of power and this means that your valve gear will have to be extensively modified so that the valves stay out of the way of the pistons when the engine is running.
It means that the compression ratio will be raised by altering the cylinder head. The inlet and exhaust ports will need modification and possibly even larger valves. The pushrods will need to be changed and you might even go to a 1250cc big bore kit and an upgraded crankshaft. The sky (or rather your budget) really is the limit!
You can add a larger carburetor or if it's an EFI model, a bigger throttle body, Nitrous Injection for short bursts of extreme boost and some altered gear ratios to keep the revs lower. You can radically alter the ignition maps and let it rev to 8,000rpm (stock is 6,200rpm).
These mods will give you up to 100 horsepower and leave you dollar-poor, but rich in adrenaline and bragging rights.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
Finding Your Happy Place
Understand your riding style and think about why you ride a Sportster. Don't just go for big numbers because while a 70 horsepower bike has usable power in the low to mid-range, a 100 horsepower bike will be quite challenging to ride in town or on anything other than dead straight and well-surfaced roads.
Lots of people make the mistake of "going for the big numbers" and then find the bike isn't fun to ride anymore. Start with Stage 1 and be honest with yourself about whether it does what you want it to do and suits your needs.
>>Join the conversation about the best mods for the Sportster right here in HDForums.
For help with your maintenance and repair projects, please visit our how-to section in the forum.
