So You Wanna Build A Custom Cruiser?

Basil Technical Articles Leave a Comment

Pick a frame, forks and wheels, slot in an engine, gearbox and primary, and then dress it with your preferred choice of tank, seat, mudguards and bars. Job done. Save yourself a fortune compared to the 25k-45k builds and get load of kudos into the bargain … but is it really that simple? We’ll be digging deeper into specific elements of a build over the issues, but let’s get a few basics out of the way first, before we get carried away.

IT LOOKS SO SIMPLE from the sidelines: don’t know why everyone doesn’t do it. In truth a few too many who shouldn’t try, do – hence the number of “unfinished projects” in the classified ads of custom mags – and a few of those who have the necessary skills are put off by the realisation of the complexity of what is entailed. Because it is complex, and don’t let anyone tell you otherwise, but it’s not insurmountable. As with most things, you need to go in with both eyes open. You need a clear plan of what you want to do and how you’re going to achieve it. You will also need a detailed budget and a sizeable contingency to cover for all the things you didn’t think about as well as those things that’ll change, because most projects will take on a life of their own as they grow. The best starting point is to work out who is going to do the work. The most obvious person is yourself, because you won’t charge yourself labour, but you have got to be realistic. If you struggle get a wheel out to change a tyre, or to switch your stock handlebars for a pair of apehangers with the attendant lengthening of the cables, hydraulics and wiring, you will be better of seeking professional help because you’ll be doing far more than that. Worse than that, you’ll also be doing it when it’s cold, when it’s damp and you’re tired. You’ll be doing it when everyone else is in the pub or on runs, and you’ll be doing it when the last thing you want to do is to lift a spanner.

If you can’t afford the time, haven’t got the expertise, or can’t give the commitment do yourself a favour and talk to someone who does it professionally because they will have all three. Yes, it will cost more because there will be a labour charge in there but there are two things you must consider: is your hourly rate of pay more or less than you’ll be paying someone else? And would it take you the same length of time to fit an engine into a frame as a professional builder, remembering that they’ll have a fully equipped workshop and special tools at their disposal? You’ll now be left with two scenarios: you’re going to do it, or you’re going to pay someone else to do it for you. If the former, you have full control and a lot of work to do and good on you. We’ve not done with you yet, but you can skip the next few paragraphs if you’re in a hurry. If the latter, you will still need to have a good idea as to what you want so that you can pick the right builder, and then you can decide, or negotiate, how much control you want to exercise, or else hand the whole project over. The choice of builder is important. If you want a traditional chopper find someone who has sympathy with that style of bike. If you want a radical show-winning state-ofthe-art custom, see who’s been winning trophies with your preferred style of bike. If you’re more interested in “go” than “show”, talk to the people who have been consistently winning drag events, and the top performance engineers. If you don’t know who they are, ask around, because personal recommendations are more useful than a list of names, and then go to see them because you have got to form a professional relationship with them. You’ve got to be able to talk to them in a language that you both understand, you’ve got to get on with them because you have ultimately got to trust them with a sizeable chunk of your hard-earned cash.

You’ll also be relying on their judgement and expertise because none of us has an unfailing sense of style or practicality. So, you’ve got your dream and your builder. What are you going to build and what from?

You haven’t got to build a ground-up custom, and it is often cheaper to start with a base bike, which takes care of lots of the main bits, but factory bikes are designed to be mass produced on an assembly line and don’t always lend themselves to easy modification. What you will start off with, though, is a full powertrain with an engine that you can test before you start, and one of everything that you need, which you can either reuse or sell to offset the cost of the new bits.

But you haven’t got to start with a whole bike at all: you can start with an engine and a frame and work up. Start with a blank canvas, draw it up and commission a frame that is perfect for your project.

You haven’t even go to start off with a whole engine, but let’s face facts: if you’re going to build an engine from scratch, either you’ll already know how to do it, or you’ll be braver than most of the rest of us. So we’ll take it as read that there’s an engine, because the rest of the decisions are common either way, and they are determined by the ultimate style of the bike so we’ll start there.

I was going to go into a round-up of the different styles here but anything that I put down would be open to my personal recollection and interpretation, and there is a strong probability that others will have different memories and the truth has been lost in the mists of time. In the absence of a potentially misleading breakdown of them, we’ll concentrate on a few basics – and boy are they basic because this isn’t so much a can of worms, as a skip’s worth.


Harley Davidson Head Stock drawing

Determine the overall shape and how it will behave. If you want a full-on Captain America chopper, you’ll have to consider how it will work. Long forks would be a pre-requisite of such a style, but would that be a high headstock, shallow rake, gooseneck or a combination of all three. Or maybe you want a bobber, or a lowrider. Perhaps a European-style streetfighter?

It’s unfair to lump them into three groups because there is so much diversity in each, but they can be so I’m going to. Hardtails are the most basic frame, but are also the purest form you can get and the easiest to build around – and to many are the only way to build a proper chopper. There are three basic types: stock original rigid frames, custom hardtails, and hardtails welded to a stock front frame loop from a production chassis.

Original rigid frames are what they are and will be covered in lugs for anything from mudguards to sidecars but will be made of the materials of their time – which means heavy. Stock frames are great for restorations and bobbers but less popular for cutting-edge customs because unmolested ones are thin on the ground and the prices are rising.

Custom hardtails can be surprisingly flexible and comfortable to ride. Modern materials and production techniques can leave you with a relatively light, clean, purpose-built frame that has enough flex to absorb the worst bumps, but still keep everything in line. Pick your rake and stretch from a catalogue, or call upon the expertise of a professional and tell them what you want of the finished product.

Modified production frames are responsible for most people’s poor experiences of hardtails. Relatively easy to do at home with a stick welder, some tube and a rudimentary knowledge of what you’re doing, they build onto a very solid front loop with little or no “give”, and often end up crucifyingly uncomfortable. A nice idea for a home-build but if you want to be any more adventurous, by the time you’ve raked and stretched your stock frame you may have well have commissioned or bought one.

Good: Great looking, simple in design and construction, and have a better chance of keeping the wheels in line as the rear wheel’s position is fixed.

Bad: Less comfortable on rougher roads, and can be twitchy on corners, stepping out on bumps with nothing more than a tyre to absorb it, and disconcerting until you’re familiar with them. All road shocks are transmitted to the entire frame and can take their toll.

Swing-arm frames are generally more comfortable, and when done right can be a lot more rideable than a hardtail. In the case of 4-speed Harleys, the clean lines of the earlier frame were interrupted by a swingarm and suspension, but the shocks can become a design feature in themselves.

If done badly, the swing-arm pivot can be a weak point, and if there is flex there, the rear wheel will not follow the front in a predictable way. Assuming you’ve got the wheels in line, you then need to make sure you’ve got the shocks right for springing and damping, and that is a story in itself. It’s worth noting here that Dyna frames don’t have swing-arm mounts on them: the swingarm pivots from the back of the gearbox, which ensures its drive-train is always in line.

Harley’s swing-arm frames are all eminently streetable in a custom context, and each has its fans with 4-speeds and Dynas making useful lowriders and street customs, and the FXR 5-speeds are a good platform for performance bikes. Good: Ideal platform for street customs, usually very rideable and not too compromised.

Bad: Often ruined for the sake of decent shocks or poor maintenance on the pivot bearing. Lacks the classic line and not the most popular route for a chop or bobber as a result. Heavier than the simpler hardtail and more complicated to make.

Harley Davidson Softail Frame

Softail™ frames provide the best and worst of both worlds. Best in that they retain the lines of the hardtail but give the comfort of the swing-arm. Worst in that they are heavier again than a swing-arm frame and the factory offerings don’t lend themselves to rubber-mounted engines, hence the 88B balanced motor. Underslung shocks are the way that Harley’s tackled their design, but the style started with hidden shocks in a more conventional position under the seat, and that is still an option.

Harley have made Softails since 1984, and every major frame manufacturer produces at least one version. There’s nothing to stop you fitting a conventional swing-arm onto the Softail’s pivot, leaving you the choice of fabricating upper shock mounts or retaining the underslung arrangement with a lever.

Good: Best of both worlds. Good looking and comfortable.

Bad: Worst of both worlds. Heavier and more complicated than a hardtail or a swing-arm, not that anyone cares.

Harley Davidson Frame Geometry

Don’t go getting the idea that all chops/ customs don’t handle. It’s a common mistake to make, and one that you might already have realised is overplayed if you’ve tried to keep up with a sorted example. That said some don’t. Some aren’t stable in a straight line never mind anywhere near a corner and this is a good area to take advice. We can all draw some lines on a piece of paper, but whether it’ll work is another matter entirely. All professional frame builders either know the engineering principles of frame design, or else have a gift, or a gut feeling as to what does and doesn’t work.

Regardless of the frame type, you can experiment with geometry to create that “look”, and a chunk of that is going to be determined by headstock height, fork rake and wheelbase. Bobbers retain much of the standard bike and just junk the excess baggage, tending to retain stock frames – predating the gas-axe frenzy that accompanied the sixties chopper boom: a that boom resulted in almost everything else. Long forks on stock frames kicked the whole front end up higher, and stretched back ends made that look less silly. Raked frames allowed the continued use of long forks but brought the engine back down to earth. Stretched or goosenecked headstocks allowed less radical rakes while keeping the same overall stance of a longer bike, but with better roadgoing characteristics.

Harley Frames Mods

The obvious best starting point is a groundup frame that will accommodate your wildest imaginations, combined with your builder’s practical experience, ensuring that you stay alive for at least long enough for his cheque to be cashed. The next best thing is an aftermarket frame that will be built to meet the current trends, and you’re likely to be able to find one easily if you’re following current trends. Then, there is always a chance that you want to use your stock frame, or that you’ve changed your mind part way through the build and decided that you want longer forks, different geometry or – more likely these days – a fatter back wheel. Don’t mock: the fattest Fat Boy a couple of years ago was based round a mere 200-section which is looking like a racing bicycle tyre compared to your mate’s 230. If you leap-frog hims for a 250, he gets a 280, you get a 300 and so it goes on.

If you want to play with forks and geometry at this late stage, or on your stock chassis, you might be better looking at trick yokes, which can create the impression of additional rake and allow the use of longer forks without cutting the metal. The resulting fork angle isn’t the same as additional rake because it doesn’t change the pivot angle, and actually has the effect of reducing the trail. This isn’t necessarily a bad thing as long as you don’t go too far. If you do go too far, you stand a chance of getting a negative trail, which isn’t clever. There are a couple of people offering a raked bearing cup set that fits into your headstock and creates a few degrees of real rake and those, combined with a modestly raked yokes, should cover most eventualities unless you’re planning on going radical. If you’re going that far, stop messing about with a stock frame and get one built.

Big wheel kits are another matter entirely. Everyone makes them, and everyone’s is better than everyone else’s. What you need to know, though, is that you can only go so far without major work, and that is about a 200-section: anything after that needs to be accounted for. A 200 is easy enough: offset the primary drive and gearbox by 25mm and stick a new swing-arm in with an odd extended nut and bolt here and there, and a longer wheel spindle. Go wider and it gets increasingly hairy with offset wheels, narrower belts or reverting to chains. Get to a 300-section on a conventional big-twin and you start to hang the primary out so far that you compromise your ability to go round left-hand bends, with the wheel kicked well out to the right … or rethink transmissions, but we’ll get to that.

Obviously V-Rods, Sportsters, Victorys have an outboard final drive pulley and different rules apply.


Whether long or short, you’ve got three basic types again: springers, girders or telescopics – which include upside-downies – and all three types can be extended, or made shorter if you want to go that route.

Longer springers came to us through the unlikely source of wartime production, designed to give a WL45 more ground clearance, and it didn’t take much imagination to realise it could be done by a competent welder. It was also apparent that it was as easy to start again as to try and extend them, and less agricultural-looking forks were the result. Straight leg springers are by far the easiest to make and are the staple of the accessories catalogues, and sit alongside reproduction forks as the main options. Hydraulically damped telescopic forks superseded them, but hydraulic damping is now an option on springers if the idea of steering with a a pogo stick bothers you. Springers typically have a shorter suspension travel than telescopics, so they lend themselves to short fork lowriders, and their leading link configuration gives them anti-dive properties. Good looking but heavy, and a bugger to clean.

Girders forks were more common on British bikes, and only really made the custom grade because they were easier to make than springers, and easier to make long versions of too. Girders lend themselves better to damping than springers, and were very popular through the eighties and nineties but they are increasingly difficult to find now in big numbers. High unsprung weight – the entire fork assembly moves with the wheel – but clean and simple.

After generations of custom builders spurning telescopics, they are now the dominant choice. Maybe Harley reintroducing springers in Softails gave a new generation of riders the chance to realise their shortcomings, but it is as likely that it’s because we’d gone beyond very long forks. It’s unfortunate in many ways, because they are the easiest to extend – just stick a longer fork stanchion into the stock slider and you’re about done – but if telescopics are too long, the angle is too shallow and the sliders don’t slide anymore. Upside-downies are nothing more than sliders mounted to the yokes and stanchions holding the wheel spindle, rather than the other way round. The advantage is that stanchions can be lighter than sliders, so you reduce the unsprung weight. Sadly, for no good reason whatsoever, normal forks are now starting to be called right-wayuppies to differentiate between them. Good, all-purpose and functional items, which also happen to be clean and good looking.

Wheels & Tyres

People are currently buying wheels on width as much as on style, and the unending search for the fattest rubber has consigned scores of Fat Boy wheels to swapmeet stalls. Just as Avon announce their 300-section, ex-Avon techie, Leo Smith’s company, Vee Rubber, announces a 360. Even the Avon on a seventeen or eighteen inch rim means you’ve got to jump through some significant hoops. Most notable changes are to your frame, but you’ve got to consider your transmission and primary, which we’ll come to later.

Wheel choice is very much a personal thing, but some combinations work well and others don’t. Laced wheels look good as a matched pair, but laced and cast spoke wheels tend to look odd. If you want the easy maintenance of a cast wheel at the back, and an elegant tall, skinny laced wheel up front, the easiest work-round is to re-use a discarded Fat Boy disk wheel, or the seventeen incher from a Deuce if you’re feeling adventurous and it’ll fit – and if you’re doing a pick and mix from swap meets, don’t forget to factor in the cost of cleaning up and finishing your bargains.

If you’re starting from scratch, the world is your oyster and you can pick for the broadest selection of wheels that we’ve yet seen. Only serious thing to consider is weight. If you’re building a boulevard cruiser, it doesn’t matter as much as if you were building a Eurofighter, but while it might not matter, you’ll certainly need to take account of it.

Wheels should always be considered alongside tyres. A low-profile tyre on the back of an FL-style bike matched to a traditional MT90 on the front looks odd, even if the tyre patterns match: it can look as if you’re still saving up for the front end. It’s less of a problem with tall skinny front wheels because you expect the contrast, but with things like the 120/70×21 on the books, there is an opportunity to maintain consistency there too. It doesn’t especially matter whether tread patterns match, but if they don’t, it is an opportunity to check that the tyre combination is good, with a safe (and legal) combination of crossply, belted and radial.

Whitewalls are a matter of personal taste, but there is some practicality to be accounted for too: pristine whitewalls and chain drives are strangers to each other, and there’s little point specifying whitewalls if they’re not available in both fitments.


It seems like a hell of a long way down the list, but in the context of American-V it’s the one that lends the least to the overall style so we’ve held it off for a while. Or were you thinking about throwing a VN800 motor or a GS1000 in? In all seriousness, you might want to chop up a cheap bike as a first attempt, but do so in the knowledge that the resulting creation will cost no less to complete, and be will worth a fraction of the price unless it is absolutely stunning.

If you’re starting from a base bike, you’ll already have your motor and no shortage of ways to tweak, tune and dress it, if you haven’t already. The potential within the stock motor is enormous, but bear in mind that while you can double the output relatively easily, that you may well over stretch the capabilities of modified bike. You can always tweak it later, once you know how it behaves on the road: few things actually change the shape of the motor itself.

If you haven’t got a motor, you can buy a brand-new knucklehead, panhead, generator shovel, alternator shovel, Evo or Twin Cam if you know where to look. If you want a sidevalve, you can still get an Indian Scout motor. Barring a new Motor Company-built Evo or Twin Cam, the rest are anything from full reproductions with modern engineering tolerances to cosmetic tributes to their ancestors, or full-on high power performance motors.

A quick round-up gives you Swedish built Knuckleheads from Flathead Power which use their own heads, Keith Black pistons and S&S generator cases and bottom end. Panheads come from Panzer, either as motors or complete bikes, and Revtech make the “Pandemonium”. Shovels from S&S can come in generator or alternator form at 93ci / 1522cc but no-one else much bothers as Shovels don’t yet have the cachet of the older motors or the perception of the Evo’s reliability. And then you get to the Evo, and who doesn’t make an Evo-style motor? You could almost be forgiven for thinking that nothing existed before it. From Zodiac’s in-house motor built from OEM and aftermarket parts, through S&S’s massive range of seven options – including a mild cammed TuV approved range – via Revtech’s own 88 and 100ci versions and up to exotica like the Patrick Racing hewn-from-solid 6061 Billet racing engine: you can slot any one into your stock frame. And in the interest of balance, there’s also offerings from STD, Zipper, Ultima, Hyperformance, DuX, and a small company that you may have heard of: Harley-Davidson – the only real Evos, and actually something of a bargain.

There are undoubtedly more, and one that will be known to a few of you: Merch Performance. A word of warning regarding Merch, however. The original company, Merch Performance doesn’t exist any more, although a new company, Merch Motorcycles Inc (trading as Merch Motorworkz) does exist and offers aftersales support for Merch performance customers. That’s not the warning though. The warning is that a company from Texas bought the scrap from the original company, including cases and barrels, from the public liquidation auction and these might get into the food chain. All cases have serial numbers and Merch Motorcycles have a list of them.

No-one’s really done much with the Twin Cam as yet, although S&S have dipped a toe in the water – actually two. One runs the older-style cases that can be used in any traditional application, while a second includes the mating surface for the gearbox for regular Twin Cam roles: neither are balanced and both are 124ci / 2025cc.

RevTech have further developed the 100- inch to create their own 110, heavily based on the Evo but with a range of their own modifications made.

With the notable exception of the OEM units, which stick to their original 80 and 88ci capacities respectively, the aftermarket motors offer a massive variety of options. S&S’s seven Evo-style motors range from 88 to 124ci – or 1450cc to 2025cc – and include a 79 and 100- inch version that will slot straight into a Shovelhead frame. And that’s just one manufacturer, albeit the most prolific.

Why a 79 and 100-inch for a Shovel framed Evo? Didn’t Harley stick a full 80- inch motor in theirs? Yes, but only getting away with it because they modified the frame. S&S haven’t gone as far as the 4.25- inch stroke with either motor, and even the 100-inch only runs to 4-inches, which it combines with a 4-inch bore to get to a square 1647cc motor that should be a revhappy little unit. If anyone’s got any experience of these things please let us know … okay, let me know.

How much power you want will determine which engine to choose, but be realistic. If you’re not going to go drag racing, don’t buy a drag spec motor, nor expect to win standing quarters on a mild-cam, low compression motor set up for loads of lazy touring torque. It’s not just that you’ll be wasting your money, but there’s a good chance that the engine will not suit your requirements, and it’s as well to look into it properly before shelling out. While you’re digging deep in that direction, take advice on the carb, ignition and pipes from the person responsible for putting it all together.

Sounds like a great cop-out, and to an extent it is. I hear different views every time I hear a fresh one and each is tested and proven by its sponsor, but they all have one thing in common: the choice of components was made by one person using their first-hand experience. Take a holistic view and you will have a set of components that was designed to run together, or at worst is known to be complementary. The last thing you want to find out is that your engine and carb and ignition are barely on speaking terms but it can, and does happen.

Cosmetics are a different matter: dressing up an Evo to resemble a panhead, or even a Knuckle is the domain of Xzotic, through CCI. Recreating the earlier motor using an Evo or even a Twin Cam as your base is possible, with a generator cam cover and revised rocker boxes, but be aware that the stock pipes won’t clear the generator cover so you’ll need the Xzotic header pipes too. These fit a Softail, but then you wouldn’t want to turn the clock back so far on a Dyna or a tourer would you? Okay, so you might, but I suspect that you’d be on your own.


There’s as much choice in boxes as there is in engines, but it’s closer competition. JIMS, RevTech, Zodiac, Baker and Screamin’ Eagle are all currently pitching for the state-of-the-art 6-speed honours and trading off their engineering reputations with a slight disagreement with regards what represents the ideal overdrive ratio. JIMS, Zodiac and Baker reckon .86:1, Screamin’ Eagle go for .89:1 and RevTech suggest .893:1 against the stock fifth gear of 1:1, providing between a drop of between 330 and 500rpm at 70mph. Be aware, however, that it is not anticipated that your motor will pull as strongly when in sixth unless you’ve got a very powerful motor or forced induction. Most 6-speeds can be supplied either as a complete box, or else internals that’ll slot straight into your stock case.

The usual suspects also offer five speed boxes for every occasion and application, and again you work on engineering reputation and recommendation for your decision. This raises something else that you need to be aware of: the actual form of the gearbox. Early FLTs, FXRs and Evo Softails are the simplest in that, although different to each other, they are a case with a gear cluster inside but with the Dyna, Harley bolted the swing-arm to the back of the ’box, and main engine sump to the bottom. They repeated the exercise with a bigger sump for the 1993-on FLHT but left the swing-arm spindle on the frame. And then with the Twin Cam motor, they bolted the engine and gearbox together directly, rather the relying on the primary chaincase as previously with rubber mount engines.

A good torquey motor doesn’t actually need more than four gears – some would say three – but that’s no reason why it shouldn’t have more. In the case of a 5-speed, it gives you more time in the meat of the power at the expense of an occasional soft-shoe shuffle on the gearshift. Five speed boxes for four-speed models are available from JIMS and RevTech, while S&S offer a modified 4- speed gear case that accepts a stock 5-speed gear cluster. And it worth saying again, in case anyone missed it last time round: the new 6-speeders are overdrive boxes, offering a top gear intended to keep engine revs down at highway speeds.

A new kid on the block is a consequence of the tyre wars, and is that thing I said we’d get back to. Right side drive transmissions are a direct consequence of the increase in tyre widths, and they are no longer rare exotica. Rather than offsetting the primary drive etc, it switches the drive to the same side as the Sportster and Victory. That frees you from the constraints of the stock outboard primary and clutch, at the cost of giving you a whole new set of engineering problems to solve and a limited range of existing hardware because few people account for taking the drive down the timing side. The primary won’t need offsetting, but you’ll need to measure up and verify that the frame and swing-arm can stay where it is, and it is a decision you really should make early.

Primary Drive / Clutch

A couple of decisions need to be made, and a couple of things accounted for. Harleys run a dry clutch, and the oil bath chaincase is only there for the benefit of the stock duplex primary chain. Lose the chain and you can lose the chaincase. Sounds simple? It isn’t.

Long before final drive belts were commonplace, the primary drive of choice was a broad, open belt. It was lighter, it was quieter and it was cleaner: they still are. Generally coming in 11mm and 3-inch widths, they come complete or as kits to upgrade your existing chain drive system comprising a pair of pulleys and a jockey-wheel tensioner, reusing everything else from the clutch hub to the plates themselves. Big fat three-inch open belts look great, uncluttered and simple, but they tend to get compromised early on. Belt guards and clutch covers are a good idea in practical use: if fingers, clothes or chunks of countryside get into a primary drive belt, it’s unlikely to stop it but will wreak terrible carnage on the intruder. And it’s a safe bet that you’ll only put an exposed leg next to a spinning clutch drum once.

And then there’s the starter drive gear, which really needs covering. I suspect I might know what you’re thinking. There’s something special about the sight of a rider suspended in mid-air, about to bring their weight – and knowledge of the ancient art of kick-starting motorcycles – to bear on the pedal that spins their motor through half a revolution or so. It is magical, mysterious and testosterone-laden. Watch the expression of shock on the faces of assembled blokes if a mere woman should dare to attempt it, and their horror – or sometimes embarrassment or shame – when they do. Kickers are wonderful things. They let you have a tiny battery or dispense with it altogether, and add to the simplicity of the bike, but it is a brave decision – especially on a big-inch motor. You need to be sure of yourself and your motor because while few things are more impressive than a single lazy, perfectly weighted and timed swing on a kicker bringing life to an engine, there are few things sadder than watching the rider disrobe, in their increasingly desperate search for cool air after the third of fourth kick of a reluctant lump of questionable parentage. It is less of an issue on stock bikes where the kicker meets significantly less resistance – my recently acquired FXS Low Rider requires less than my TR6P Triumph used to offer – but it’s always remembering that while lack of fuel or a spark will have you working yourself into a lather, a mistimed spark has the potential launch you over the bars, or have you hobbling around for a week in some distress.

As ever, if you’re going to ride it, be realistic. You’ve got to be able to start it so make sure you can. If it’s going to be a good looking bike, people will gather to watch and listen to the bike that has attracted their attention pull away. Can you feel your cheeks redden just thinking about it? By all means add a kicker as a back up, but we’re old and wise enough these days to accept the advantages of an electric foot.

If you’re wondering why you’d want a skinny 11mm belt rather than a whopping 3-incher, they are meant to go inside the chaincase. Harley tried that trick with the original Sturgis but dropped it after a couple of seasons, deciding it was too hostile an environment, but technology has moved on. If you do run a belt inside the primary chaincase, make sure all means of oil getting in there are correctly stopped, and if you’re concerned about heat buildup, you can pick and choose from a range of slotted and vented cases, or get creative yourself with a Dremel on a stock one.

Fuel, Exhaust, Ignition

You’re on your own here, or rather at the mercy of either the factory, your builder’s or your own experience and your confidence in the advice of your friends.

If you’re starting from a base bike, you’ll already have everything you need but probably a desire to bin a lot of it. Only do so when you have a plan as to what you’re going to replace it with.

If you’re starting from scratch, the first place to start is with the engine manufacturer’s recommendations and work from there.

Increasingly, you will come across a choice of carb or injection, and it’s worth being aware that the choice will become increasingly limited for new builds as the limits on emissions are tightened up, because they will inevitably have to comply with current standards at some point. We’re in the clear currently as far as the SVA goes, but don’t rely on such leniency for ever.

No matter how firmly you adhere to the principle that loud pipes save lives – and there’s no doubt that people notice you with straight-through pipes – noise regs are always going to be our nemesis, but as long as the police focus on sport bikes with loud cans, and go easy on bikes that look like they should make some noise, we can breath a collective sigh of relief … but there’s noisy and there’s noisy. Take the mickey and you’ll be asking for it, and will ultimately contribute to bringing forward the date when public opinion will force someone to take action.

Ignition is lumped into this group because while it doesn’t deal with the fuel, and while it makes no noise, the choice of unit is very dependent on what combination of fuel and exhaust system you’re playing with. You can get programmable units that will cover most eventualities, but it’s not a bad idea to match that module to the rest – and if pursuing the injection route, it can form part of the overall engine management system.


Good brakes save lives. Bad brakes don’t stop you riding quickly, just make you more aware of your own mortality.

One area where I’ve never heard dissent is in the technical improvement in braking over the generations. No-one in their right mind is going to finish off their retro Panhead lookalike with drum brakes, unless they’re proving a point on a full-on restoration.

Well, not if they’re going to ride it.

Drums are good in the wet because they keep their linings dry, but they are prone to overheating under duress and fade when they do. What would stress out a drum? Weight at speed. You’ll be more likely to find someone trying to fit disks to their original Pan than the other way round, and you’d be wise to follow their example.

Just as we’ve come to accept telescopic forks, so too have we learned to live with exposed disks, and learned to whinge about the arresting properties of older technologies. It’s good to see, because it wasn’t too many years ago that tall skinny trail bike front wheels, complete with their minimal drum brakes, were being pressed into use as anchors on 600lbs roadbikes. It actually isn’t as stupid as it sounds, because while the front brake does the vast majority of the work on a modern sport bike and the merest hint of pressure on the rear wheel will lock it up, the back wheel on a heavy American bike is unlikely to lock and plays an important part in bringing the bike to a stop. In fact, it wasn’t a legal requirement in the US for a long time – I would look it up, but it’s not that important – and a lot of competition bikes didn’t have them … mind you, they didn’t have back ones either.

We’ve got a full-on tech on Brakes scheduled for sometime soon which will go into much more detail, but the important thing is to be aware that cast brake calipers aren’t as accurate as a good billet ones, which also give greater feel.

If you wondered why four pots look like twin pots, it’s because there are pistons either side of the disks pushing the pads into contact with them, as opposed to a single piston in a single pot pushing one pad and levering the second into contact. The result is a better, flatter, more consistent contact between multiple pads – typically one per piston – and the disk, and an opportunity to put more pad friction surface in firmer contact with more of the disk. Ditto with six-pots.

Disk size doesn’t massively affect the amount of disk area the pads can contact, but does affect how easily it deals with heat. Bigger disks absorb heat better, and heat is still an issue on disk brakes, just nowhere near as critical as with drums.

Drilled brake disks look pretty, but they do nothing for the contact area. What they do do, is make the disks lighter and as a high grade carbon steel, they are a fairly heavy metal in an area where you’d prefer less weight – which is why race bikes used carbon disks. Drilling can be overdone, and drilled disks are typically harder on pads than smooth ones.

Two disks aren’t always better than one, but they work wonders for symmetry and people will swear blind that it’ll stop the bike in a straighter line. The downside is that if one disk is heavy, two disks are twice as heavy.

Dressing It Up

The frame and forks may dictate the shape and the wheels might allude to something but until you’ve stuck mudguards and a fuel tank on your bike, it could still go in one of many ways.

Arguably, having determined what you want it to look like, you should be barred from seeing it as an undressed rolling chassis because if you’ve never seen a bike in that state before you might have your head turned. Everything is tiny, and the more you add to it, the further from that pure form it moves. It’s the same when you see the dressed bike without the clutter of cables and wires, when it looks finished but you know it’s not, but we’ll get to that in a bit.

If you’ve got this far you’ll know whether you’re looking at a high-tunnel Sportster or oversized fat bobs, you’ll have already worked out how much of a valance you’ll have on your mudguards and you’ll know how high, wide or both your bars are going to be. It really doesn’t matter what my opinions are because it’s not my bike, but the hope is that it all hangs together as you hoped, with or without the input of your builder or friends.

The most important thing at this stage is to bolt everything together without any paint or special finishes. A drilling in the wrong place will come to light and can be accounted for here much more easily than later. A poor fit can be beaten into shape more easily without fear of damaging paint or brightwork. It doesn’t matter whether you’ve sourced a part that is designed to fit on exactly the right model and year of bike as your, because that’s still no guarantee that it will. This is the dry build and it is essential. If you’ve built the bike from scratch, or in any other way need to put it through SVA, this is the state that you’re best advised to get it checked in. If something falls foul, you can amend it without too much heartache, but remember that SVA needs to be done on a fully funning motorcycle. It doesn’t need paint or chrome, but it needs oil, fuel, sparks, lights and brake fluid.

Finishing Off

Having gone as far as the final bike in bare metal, you’ve got the joy of taking it all to pieces again to send to the painters, chromers, and polishers. If you’re doing something tricky with the paint, they might want to see the bike in its complete form for marking up so give them the chance, but otherwise strip it and make a careful note of what goes where, because it’ll be a few weeks before they go back. You don’t need telling not to use old fasteners do you? In some ways, this is an even more sensitive moment than seeing it before the bodywork is added, because as you conduct your slow metal striptease, the bike shrinks before your eyes and now isn’t the time to change your mind. Actually, that’s not true. It is the last chance you’ve got to change your mind before the final die is cast, but you’ve got to draw a line under it at some point.

This is when you’ll realise that it isn’t exactly what you want, because nothing ever will be. When you decided what this one should be, it was months ago and that was what you wanted months ago, but as it evolved, and as you’ve taken on other external influences, that will have changed.

That’s why people go on to build a second, and a third bike and one of the reasons why a lot of people trust the builder’s judgement, on the basis that the bike will be influenced by their instructions rather than built to a precise specification.

And why people buy new Harley custom models: Harley’s styling department act as the builder and you are still the customer. The only significant differences are that rather than building just the one, they are knocking them out by the thousand, and that they try to second-guess what you want based on what influences they are subjected to … their trick is to provide enough scope to let you take it to the next stage.

Words: Andy Hornsby of American-V Magazine – Originally 2004

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