BUYERS GUIDE TO PERFORMANCE PARTS

Buying Performance Parts For Your Bike

If you've ever looked through a parts catalog, then you know that there's literally thousands of brightly colored after-market parts, with snappy names, claiming to give your bike INCREDIBLE POWER INCREASES!  Now if you look at the price tags for these items you’ll understand why the saying goes “you can make your bike as fast as you want to spend.”  Its also important to note that the amount of increased power you can squeeze out of a bike is subject to the “law of diminishing return.”  That is, if it costs $300 to get your first 20% increase in horsepower out of your bike, it will likely cost around $10,000 to get the last 10%.

You’ve likely seen parts referred to as stage 1, 2, or 3.  This is because engines should be modified for performance in stages.  By working systematically through the stages, you’ll ensure that you’re getting the biggest boom for your dollar.

Categories of Performance Parts 

There are basically five systems that you are upgrading to increase your bikes performance.  They are Intake/Fuel, Exhaust, Ignition, valve train, and displacement.

Intake

 

Intake is pretty straightforward; if you get more air into the engine, it can make a bigger explosion.  Fuel is directly connected to this, as you must increase the amount of fuel in proper proportion to the increase in air.  (This is covered extensively in the previous post Carbs 101) (Oh and if your bike is EFI you are going to hell)

Higher performance is here begins with a high flow air filter, and ends with high flow heads.  Don’t get carried away with flash; my advice is to spend wisely and save your money for more performance.

Note* velocity stacks don’t filter the air and are truly meant for racing.  Don’t run velocity stacks unless you love cleaning your carburetor.

Exhaust

For many v-twin owners, the first modification is to swap out those stock exhaust pipes for some stylish drag pipes.  While this will make your bike heard for miles, it does little to nothing to help performance.  As far as performance goes, nothing can beat a good 2into1 exhaust. I know it seems counterintuitive to cram more exhaust into one pipe, but these systems allow the exhaust to work off of each other’s momentum and create a broader power band.  Typically high-end sport bikes will come stock with a great exhaust system, but that doesn’t mean that you can’t spend 2-3k for one or two more ponies.

Ignition

Simply put, a more complete combustion will create more power, and in order to get better combustion you’ll need more electricity at the spark plugs.  Upgrades begin with higher performance plugs and wires. The next step is different depending on the type of ignition your bike uses.  A high performance kit for a CDI unit, for example, will consist of high voltage coils and pickup coil.  Ignition kits are common and affordable.  Just make sure you buy a reputable brand.

Valve Train  

The valve train may use either a pushrod system, or overhead cams.  Either way the goal is the same.  In order to get more power, you need the valves to open wider and stay open longer.  This requires swapping out for high performance cams with more aggressively angled nodes.  Lighter push rods, rocker arms, and valves will help prevent you from floating valves when using these high performance cams.

Displacement

Upgrading an engines displacement seems like one of the most intuitive upgrades.  (If you want more power, get a bigger engine)  This, however, is not always all its cracked up to be.  First off this is one of the most expensive and labor-intensive upgrades you can make.  Second, while upgrading to a larger size engine will make more power, it may not change the power band in the areas you want.

   

So what should you do when?

Here’s a chart of performance stages that applies to most bikes on the road.

 Performance Stages

Hopefully this helps you wade through the sea of performance parts, and start spending your money more effectively.

THE ART OF THE OIL CHANGE

THE OIL CHANGE

involves more science than you knew

So you’re going to change the oil in your bike…. Great decision!  There is little maintenance as important as keeping fresh oil in that engine.  But which brightly colored can of oil should you be using?  It seems like everyone you talk to has a different opinion of what's best for your bike.  

Here we’ll cover the science that goes into motor oil, and help you make an informed choice when buying that sweet black gold. 

Grades vs. Groups

In order to make an informed purchase you should have a basic understanding of what’s actually in a quart of oil.  Basically, there are two primary classifications of motor oil that you should be aware of; grades, and groups.  The grade refers to the oils weight (viscosity), while the group is the chemical makeup of the oil.

Grade/ Weight (Viscosity ratings)

Oil is rated on its label by weight, (ex. 15w40) this is to let you know just how viscous the oil is.  (the higher the number, the thicker the oil)  There is allot more to this number, however, than most know.  For starters, the “w” stands for “winter” not “weight.”  This is because multi-grade oils (oils with two weights) are rated for two different temperatures.  The first number is the oil’s cold start weight, measured at 0 degrees celsius; while the second number is the oil’s weight at running temps, measured at 100 degrees celsius.

These multi-grade oils are created by adding magical molecules chains, called viscosity index improvers(VII’s).  The VII’s work their magic by curling up small when their cold, and stretching out when their hot.  This allows the oil to behave differently at varying temps.  The amount of VII’s that go into an oil then, control how large the spread is between the two numbers.  The amount of VII's is stated as the VII factor, which is simply the quotient of the two weights.  Example: a 10w40 oil has a VII factor of 4 (10/40=4). Make sense? 

The VII factor is important because these VII’s can break down under the pressure and churning that normally occurs in a motorcycle engine.  Because VII's act to thicken a naturally thin oil, VII break down lowers the high temp viscosity and inhibits the oils ability to lubricate a hot engine. Its been shown that under normal running conditions, a non-synthetic 10w40 can actually be reduced to a 10w25 in as little as 1,000 miles.  For this reason, non-synthetic oils with a VII factor of 4 or more should not be ran in motorcycles for more than 1,500 miles.

Single grade oil, on the other hand, is very straightforward stuff.  One weight, tested at 100 degrees celsius, and no VII’s.  This can be the right choice if your bike lives somewhere with very consistent temperatures, and is always given ample time to warm up before riding.  Without any VII’s, single grade oil offers a longer life and offers a more consistent high temp viscosity.  (use wisely)

Note* oil weights represent a small range of viscosity, so one 40 weight may be slightly heavier or lighter than another.

Oil Groups

Oils are further Grouped as type 1 through 5, based on the way they are refined and what they come from.  All non-synthetic motor oil comes from liquefied dinosaurs, which is sucked out of the dirt.  This crude oil is often lousy with paraffin wax, tar, and aromatics. (all bad things) 

• Type 1 oil is basically just dino juice strained through clay and solvents.  This leaves type 1 oil with a about 15% wax and tar content, and only about 85% good engine protecting oil.  This should only be put in your bike under apocalyptic circumstances.  Type 2 and 3 oils are further refined using a De-Waxing process that significantly increases the yield of pure oil.
• Type 2 oil uses a distilling method to remove nearly three times more wax and tar than the type 1 method.  The resulting type 2 oil has a only about 3% impurities and 97% good stuff.  This is still not good enough for your bike.
• Type 3 oil is far and away the purest of the dino juice categories, and was only developed in the late 90’s.  Type 3 oils use a chemical De-Waxing method to remove virtually all wax and tar, allowing them to be run for more miles and protect better.  Type 3 oils perform comparable to synthetic oils at running temps, and are even marketed as “Synthetic.” (if you're paying less than $12 a quart you're probably using a type 3 oil) 
• Oil producers have attempted to overcome the slight shortcomings of type 3 oils by blending with true synthetic oil.  However, even a blend cannot fully match a true synthetic.
• Type 4 and 5 oils are commonly referred to as synthetic oils.  Basically the difference in the two lies in where their base oil comes from.  While type 4 base oil starts with a chemical called olefin, type 5 starts with plant and animal based cooking oils.  It looks like in the near future we will also be seeing a type 6 created from liquid natural gas.  These base oils then go through an intensive process of mixing chemicals and bonding molecules, to create a man mad motor oil.  Group 4-6 oils all seem to perform the same, but differ in production cost of their base oil.  Synthetic oil has enormous advantages since it is chemically engineered for the specific task.  Synthetic oil has superior film strength, allowing for safer starts; better low temp performance without the need for high VII content; a higher flash point, protecting you at redline rpm's; as well as lower oxidation and acid buildup.

True Synthetic motorcycle oils I recommend: AMSOIL, SPECTRO, MOTUL, & REDLINE.

Lastly, Additive Packages

Its important to note that oil producers place a wide variety of additives in their oil such as solvents, buffers, detergents, and additional lubricants.  While these additives serve a purpose, it’s important to keep in mind that not every additive package is suitable for every engine.   For example, 0w-20, 5w-30, and 10w-30 non-synthetic oils are termed energy conserving, meant for small cars, and should not be used with a wet clutch.  EVER!

So we now have a pretty good list of non-synthetic oils you should NOT be running in your bike: 0w20, 5w20, 5w30, & 10w30 can cause clutch problems when ran in a wet clutch due to their additives; 5w20, 5w30, & 10w40 breaks down quickly due to a very high VII content; and all single grade oils should be used with caution.

So what’s left?

Well basically you’re left with 15w30, 15w40, 20w50, or a 25w60.  (Note* a true synthetic 10w30, or 10w40 is safe as well)

So What Grade Oil Should You Use?

It’s best to use the grade of oil recommended in your owners manual.  This can become difficult, however, when you're riding in conditions wildly outside of what the bike was designed for (ex. riding a 60s’ British bike in Arizona), when you don't have an owners manual, or when the bike manufacturer attempts to hide this information so you’ll use their brand of oil.

The grade of motor oil called for to be used in your bike is based on some specific engineering that went into your bike, as well as the temps it was expected to operate in.  There is some room for you to make changes, but it's important that you do it right.  Based on high temp shear viscosity tests, there are really only three choices for high temp oil weights:

High temp weight

1. 20
2. 30 - light 40 
3. heavy 40 - 60.  

Basically all the high temp weights within a particular line will behave about the same.  So you could switch from a 50 up to a 60 if your spring to summer weather fluctuates drastically.  However, you should NOT switch between weights in different lines. (cannot go from 30 to 50)

For the low temp weight, its really about film protection and protecting your bike during warm up.  For this reason you have a little more room to decide whats best for your bike, however remember what we talked about earlier regarding VII's.  For the low temp you want an oil thats liquid enough to pump around the bike when you hit the start button, without being so thin that you sacrifice film protection.  A 5w will be safe to start as low as -13 degrees fahrenheit, while a 20w is only safe down to about 30 degrees fahrenheit.

Be smart about this, and don't test out a new weight oil in your bike with a 2,000 mile trip. 

Here is has a great database to help you find the right oil for your bike provided by AMSOIL.

I have also created a couple tables to help out Harley owners:

*Don't forget the oil filter*

Here's a couple vids covering the process of changing your bikes oil:

• Harley motor oil change
• Harley primary oil change
•  Sport bike oil change
• Suzuki GZ250 oil change
• Yamaha V-Star 1100 oil change

Special plug for Fix My Hog.  I received their Harley Maintenance & Performance dvd free from Dennis Kirk, and was pleasantly surprised.  It’s a comprehensive guide filled with helpful tips.

Sources:

• All About Oil
• A Study of Motorcycle Oils
• Wikipedia - motor oil

Carburetor's 101

Carburetor's 101 - (why it works and what makes it better)

Theory:
Most people know how fuel injection works, but many people wonder how the fuel ends up in the engine without the assistance of a pump and fuel injectors.  The answer is MAGIC!!!  This magic can be demonstrated by blowing across the top of a straw that is sitting in a drink.  As you blow, the liquid is drawn up the straw and eventually sprays on the girl sitting next to you.  This is known as suction. (yes I know suction doesn't exist and its simply equalization of differentiating pressure zones)

So a carburetor basically consists of a float bowl, which is effectively the cup; jets, which are effectively little straws sticking up out of the cup; and the venturi, which is the tube that air flows through.  As air is sucked through the venturi of the carb, it rushes across the top of the jets, which in turn draws gas up the jets and sprays into the engine.  This process of combining fuel with air is known as atomizing the fuel.  Simple right?

So if the amount of atomized fuel being fed to the engine is in direct relation to the amount of airflow going through the carb, how is the airflow regulated?  Well the answer is what separates one carb from another.

There are basically two types of carburetors; the Butterfly Carb, and the Slide Carb. (& one more)

• The Butterfly Carb: (left pic) uses a pivoting throttle plate which turns sideways to increase airflow.  Butterfly carbs include the SU, S&S, Linkert, Zenith/ Bendix, and Keihins between 1976 & 1989.  Butterfly carbs are simple and easy to tune, however they can only handle being opened up so much before the low speed becomes mushy.  Over-carburetion is a common problem with people trying to get more power out of butterfly carbs.
• Pro's: they are very responsive at high RPM's, and the modern addition of secondary circuits and accelerator pumps has helped them to maintain smooth overall responsiveness.
• Con's: even wide open, the throttle acts as an obstacle for airflow, also butterfly carbs are highly sensitive to changes in altitude.

• The Slide Carb: (right pic) uses a slide to open or constrict the size of the venturi, in order to control airflow through the carb.  The slide carb also uses a needle to better control flow from the main jet, which extends straight down from the slide.  Slide carb's include the Mikuni, the Edelbrock/ Quicksilver, and most Keihin carbs.  The slide carb has potential to create significantly more power than the slide carb, and a smother transition from idle to full throttle.  This is due to the slide forcing airflow down and near the jets, as well as not having any obstacles for the airflow to traverse around at full throttle.
• Pro's: responsive throttle feel, high airflow, and less sensitivity to changes in altitude.
• Con's: because fuel can't react as quickly as air, low speed throttle response often requires a bewildering number of circuits with individual jets to control the airfuel mixture.  This can make tuning a slide carb one hell of a job, and if its not tuned right all the advantages go out the window.

Note* circuits & air fuel mixture: complete combustion is achieved in a gasoline engine at an air to fuel ratio of roughly 15:1 respectively.  Circuits are used to maintain this ratio as RPM's climb from idle to full throttle.

• The CV Carb: (above) the CV, or Constant Velocity carb, is essentially a hybrid carb which combines a throttle plate with a venturi slide.  Essentially the throttle plate is controlled by your wrist, while the slide is controlled by vacuum.  (I know its not really vacuum; the slide is driven by its need to equalize the pressure inside and outside the slide)  So the same phenomena that sucks fuel up through the jets also raises the slide, lifting the needle and opening up the main jet.  Because the main fuel jet in the CV carb is directly controlled by airflow, this carb is able to compensate for changes in elevation by only reacting to the amount of air available.  (if you climb in elevation you'll still loose power, but you wont be running overly rich)  
• Pros: this carb is the go-to for stock applications and 60's race cars because its partially self regulating, it forces airflow down and across the jets making for very respectable power, and its easy to tune.
• Cons: this carb has two obstacles for air to flow around giving it the slowest air velocity of the three, and because the slide is controlled by something other than your wrist it has less throttle response. 

Tuning and Jet Kits:
The primary way to tune your carb and boost performance, is to change those stock fuel jets.  Jet kits are available from many brands such as Yost Performance and of course Dynojet.  While some are meant to be used in combination with performance parts, others are simply meant to fix trouble spots in the stock application.  These trouble spots are not necessarily the result of negligence by the highly paid factory engineers, but are purposely placed there to make environmentalists happy.  (this is why most new bikes will experience an immediate power gain from installing a jet kit)
In order to maintain the 15:1 air to fuel ratio discussed above, any performance modifications that change the amount of air going into or out of the engine, will require you to change the size of your fuel jets in order to keep to this ratio.  Most kits will provide a table matching up your bikes modifications with the proper jet size, however a trip to your local dyno-testing center can give you a much more accurate picture of what size fuel jets your carb really needs.

Note*  jet kits for Slide and CV carbs include a needle that directly matches the shape of that brands main fuel jet.  Don't mix and match unless you know what you're doing.

If you are normal and you don't have the resources to get your bike dyno-tested.  The next best way to tune a carb is to find an open stretch of road and take notes on the bikes performance.  Heres a rundown of this process:

First, to check the high speed hold the throttle fully open, bringing the bike above 75% to redline, and then drop the throttle to 7/8 open.  If the bike accelerates slightly, the bike is too lean and you should switch to a larger main jet.  If the engine hesitates or misses slightly, the bike is too rich and you should switch to a smaller main jet.  Ideally, your bike should just slow a slight amount.
Second, to check the midrange hold the bike steady between 40% - 70% to redline.  If the bike is hunting or surging the main or intermediate jet is incorrect.  To find whether it is too lean (small) or too rich (large), snap on the throttle.  If the engine pops or cuts out, its too lean.  If the engine blubbers and farts, its too rich.
Last, check the low speed idle jet.  This is a different process, because the idle jet is fine-tuned using the mixture screw.  The process of setting the mixture screw is slightly different for each carb, but here is the basic process:

• Starting from scratch: turn the mixture screw in counterclockwise until it bottoms out with light pressure.  Turn the screw back out 1 3/4 turn.  Now warm the bike up to normal operating temp, and set the idle speed between 900-1000 RPM's.  Turn the mixture screw inward (clockwise) in slow 1/8 turn increments (wait a few seconds in between turns) until the engine begins to falter.  Next turn the mixture screw outward (counterclockwise) in the same manor as before, and stop when the engine again begins to falter.  Give the screw 1/8 turn inward and you should be done.  
• If from the 1 3/4 starting point you had to go more than 1 full turn inward before the engine began to falter, the idle jet is likely too small.
• If from the 1 3/4 starting point you actually had to go outward more than 1/2 turn to find the first falter point, your main jet is likely too large.
• Additionally, if after the bike feels sluggish off the line, try turning the mixture screw inward 1/8 turn.

Chang of Altitude:
Lastly its worth wild to discuss the effect of altitude.  Weirdly enough, it seems that those of us who live near the ocean are always taking rides up into the mountains.  While the people who live in the mountains always want to take rides out to the ocean.  Because we're never content at our present elevation, our air fuel mixture is constantly being stressed.  This due to the fact that air pressure drops roughly 1 psi for every 1000 feet climb in elevation.  With a starting point of 15 psi at sea level, this means that at the end of a trip from LA to Tahoe your bike will have 20% less air available for it to breath.  Your bike now has 20% less power and, if your not using a CV carb, you're likely running too rich.  If this is a quick day ride you have nothing to worry about, other than potentially getting passed by Honda's, but if you're going to be riding at that elevation for long you should re-jet to avoid engine damage.

So thats it..... hopefully this was helpful to demystify carburetors, and build up your d.i.y. confidence.  Please comment or send me an email if you have any question.

Sources & Links:

• Sportster/ Buell Engine Hop-Up Guide - Kip Woodring
• CV Performance
• Catalog - Sudco
• Video - CV Carb Demo

METAL ENGRAVING BIKE PARTS

Metal Engraving

some basic tips and general knowledge

This piece is the clutch cover for a 97 HD Sportster.  Aluminum is a non-ferrous (fairly soft) metal, making it easy to work with. I started by reading every book I could find at the library (which wasn't much) and watching every video I could find.

The process I used was a basic hammer and chisel, mostly due to cost.  Other options range from push engraving (works for softer metals), pneumatic engravers (an air tool that basically does the hammering for you), and using a dremel (I opted away from this because the spinning seems to take away control). I bought two chisels from a jewelry supply company.  One FLAT HIGH SPEED STEEL #39 (1 mm), & one ROUND HIGH SPEED STEEL #54 (1.2 mm).

First things first; gotta get a design on the piece that you'll be carving.  I used a technique called pouncing (printing onto paper, poking lots of little holes into the paper along the outlines, and then drawing on the paper with something that will go through the holes transferring a dotted pattern on your piece)  Note* its important to get your design perfect before you start engraving, because its hard to freehand engrave a design if you're a beginner.  I chose a quote from Fear and Loathing in Las Vegas, surrounding the Gonzo Journalism logo.

Its also very important to have a good surface to work on.  What worked the best for me, was a cement picnic table in a local park.  I put down some rubber shelf and drawer liner to keep the piece from skating around while I was chiseling.  Simple but effective.

Basically the process that I developed went like this:  Im right handed, so I held the hammer in my right hand and the chisel with my left.  I started using the flat chisel since it seamed better at removing large chunks of metal.  Holding the chisel at a steep angle, I made one or two strikes to get it to plunge and then quickly flattened out to prevent it from boring straight down into the metal. The hammering has to change depending on what the chisel is doing.  For example, to make a straight line I was able to hammer harder and slower, however to make tight curves I would hammer much faster and lighter.  (Note* always be hammering)  To keep from breaking the tip off your chisel's, always be hammering if the chisel is moving.

After getting the design looking good and all the depth fairly consistent, I went back over all the lines with the slightly larger round chisel to give the valley of the engraved lines a smoother look.  I did the majority of this work by simply pushing the chisel through the material, (push engraving) because I didn't want to risk boring any deeper.  This is the time to clean up all your lines and curves.  Alternate from pushing flat through the already established lines, and cutting out additional material from the side of the lines by pushing the chisel down at a steep angle.  Finally I went over all the lines with a scotch bright pad, to knock down the sharp edges, and finished with some MOTHERS ALUMINUM & MAG POLISH.  For a little extra effect, I also rubbed some lacquer paint into the relieved lines.

It may not be factory perfect, but its a hand made part that I can show off on my bike.

Links:

• Video - Hand hammer engraving copper
• Forum - Good additional hand engraving info

CONVERTING BIKE TO SOLO-SEAT

Slimline Solo Seat Install

(not done to showbike standards)

81 Yamaha xJ650 Maxim.  This was a 4 year project that included re-painting, 15" ape hanger handle bars, forward controls, and making the switch to a slimline solo seat.  This bike was a great time.

Switching to a solo slimline seat was an intimidating job, made harder by the fact that I was doing it in an apartment parking lot.

After taking off all the old seat garb, I cut the frame with a cheap angle grinder.  (you don't need a $200 grinder to do a job this size)  Then I cut up some 1 1/2 flat steel stock to make the mounting hardware for the new seat.  I made two pieces out of the flat stock to fit with the triangle bolt pattern under the new seat.  One bar ran from the mounting bolt on the gas tank to the front of the seat. (see center picture)  The second bar ran horizontally between the two frame rails for the back of the seat to sit on.  (I did this for 10% the cost of buying pre-made mounting hardware)  Then its just a matter of painting the new hardware, and bolting the hardware to the bike and the seat to the hardware.

my seat mount without springs

seat mount with springs

Some mounting kits come with weld-on hardware, however the mounts shown above can be simply bolted on.

Not show bike quality, no welding, but who cares cause it worked.

Not really that big of a job, but it gives the bike a severely customized look.

Links:

• How to install weld on mounts -  from the guys at Lowbrow Customs