V STAR 1100 HIGH COMPRESSION PISTONS
The basic principle of the combustion motor is drawing fresh air into the cylinder while mixing it with fuel, next compressing it, then igniting it, and lastly expelling the waste (or exhaust) and then starting again. In general the tighter you compress the fuel and air mixture, the more efficient and powerful the combustion. Stock pistons in the V-Star 1100 deliver an 8.3 to 1 compression ratio. This is generally considered a low compression engine. It is able to use low octane gas, and actually a stock engine will run better using low octane gas. Also lower compression engines are generally easier to tune for mass produce from the factory.
Installing our 10.6 to 1 or 10.25 to 1 compression pistons are the essential building blocks to begin building a performance engine. We have spent many hours testing and retesting many compression ratios of pistons. Both higher and lower. We have found that with the V-Star 1100 engine 10.6 is the ideal compression for performance, reliability and longevity. 10.25 to 1 is ideal for customers that are looking for increased performance, but do a lot of traveling (i.e. higher and lower altitudes). A bit less compression will allow more variance in tuning as oxygen levels change with altitude levels, etc.
Many people ask, well if 10.6 to 1 compression is good, then why not go higher? Why not 11 to 1 or even 12 to 1? The main problem with going higher is pre detonation, or what is commonly called pinging. This is caused because the tighter you compress the fuel/air mixture the more volatile (or explosive) it becomes. Add to that, the fact that higher compression also develops more heat and you chance of pre detonating are greatly increased.
Detonation of the air fuel mixture is started by the spark plug just before the piston reaches Top Dead Center (or TDC). The reason the fuel is ignited just before TDC is because all of the fuel in the cylinder does not ignite instantaneously. The explosion actually starts as a small ball of flame created by the spark plug and then rapidly expands to fill the entire chamber forcing the piston back down, creating the power that ultimately pushes your bike forward. The amount of time it takes for all the fuel to ignite, should be the time it takes for the piston to fully reach the top of it's stroke and begin its travel back down the cylinder. So going with a too high of a compression piston creates 2 compounding problems: 1) Increased heat, and 2) The increased volatility of the air/fuel mixture because of the higher compression. When these two conditions combine, the probability of spontaneous igniting of the air and fuel without the actual ignition being caused by the spark plug is greatly increased. This happens before the piston has a chance to fully reach to position necessary. This is called pre-detonation. Pre-detonations causes a pressure wave, which reverberates throughout the cylinder, causing adverse effects to the combustion cycle, and high amounts stresses on the engine. If it happens too soon before the piston reaches TDC, it also pushes down hard AGAINST the piston on its compression stroke. This causes a sudden loss of power and bucking of the pistons, rings, pins and rods, not to mention very high stresses on the bottom of the engine including the crank. Even if pre-ignition does not cause audible knocking, it causes higher temperatures and pressures in the cylinder that can cause rings to fail and even cause aluminum-alloy pistons to melt. Not pretty. Keep in mind at just 4000 rpms the piston is firing at and amazing 33 times per second!
Don't be fooled by competitors that promise more power by higher compression. It simply isn't true, or it isn't safe. Do a bit of research before you purchase from us or anyone. You will notice that even the most renown cruiser engine builders very rarely ever use compression ratios over 10.25 to 1 for v-twin motorcycles. This is why we have done many, many hours of testing and retesting to be sure that we are producing a product that is going to provide plenty of enjoyment. Oh, so you caught that.... So you ask... If these engine builders rarely use higher than 10.25 to 1 compression pistons, why do you recommend 10.6 to 1? Great question. The simple answer is this, remember the comments about the creation of heat causing an increase in pre-detonation? Well most cruiser ( V-twin) engines have cylinders which are quite close together (45 degrees or even less), so they require a long y type intake manifold for the side mounted carburetor, meaning the air/fuel mixture must travel nearly 6 inches or more before entering the hot combustion chamber. The V-Star 1100 (with a 75 degree motor) on the other hand has two carburetors situated between the cylinders. Each of them has about 1 inch of intake manifold, and the carbs are situated in position that fuel is able to be almost direct sprayed into the cylinder. When the cool air/gas hits the top of the cylinder and piston it creates additional cooling which helps delay combustion which allows the 1100 motor to safely use 10.6 compression. Hopefully this helps, if you have any more questions feel free to call us!
V STAR 1100 HIGH LIFT CAMS
Since the V-Star 1100's engine is a Single Over Head Cam (or SOHC), changing the cam is a very simple process when compared to doing other internal engine work. Changing the cam does not require pulling the engine or highly advanced tooling. Basically, if you are mechanically minded, and know how to gap your own valves you can change your cams.
Here's how the cams work (the V-Star motor has 2 cams, 1 for each cylinder). Each of the cams have 2 lobes on them. These lobes press against the rocker arm which in turn presses against the intake and exhaust valves. There are 4 main working positions of the valves,
1) Intake valve open as the piston moves down, which draws in the air/fuel mixture from the carburetor.
2) Both valves (intake and exhaust) closed to create compression as the piston rises to the top of its stroke.
3) Both valves closed as the piston returns back down under the power created by the combustion of the air/fuel mixture.
4) Exhaust valve opens as the piston returns to the top driving the burnt air and fuel out of the cylinder and into the exhaust pipe.
Those are also the 4 strokes of a 4 stroke engine. As you can deduct, the farther you open the valve the more air is allowed to rush in. Therefore creating more available combustible mixture, and thus generating more power. This is what a high lift cam does better than a stock cam.
So you may ask, why not use a very high lift cam? Wouldn't opening the valve all the way possible be the best? In short, not necessarily. First, too high of a lift creates more potential of piston to valve interference. It also creates more potential of floating a valve at higher RPM. Floating is when the motor is turning fast enough that the valve springs do not have enough force to keep the cam against the rocker arm, in turn not closing the valve quick enough. Stock valve springs are capable of safely handling a 450 lift cam. All of our X series cams achieve a 438 lift and are designed to work with stock valve springs.
Our Triple Z cam provides nearly a 500 lift! This camshaft must be used with our dual valve spring package to provide the force needed to close the valve safely with the added lift. This camshaft is arguably the most advanced cam for the V Star 1100 on the market today with much less valve overlap than the competitions ultra high lift cam. Less overlap means less decompression, which means more bottom end torque. Unlike the X series cams, the Triple Z cam will require pulling the motor in order to install the dual valve spring setup in your heads.
All of our cams utilize a hardface nickel based welded lobe containing complex microscopic bi- and tri-metallics. This is by far the most dependable and longest lasting way to build a cam. This process requires the return of a stock cam set (called a core) from each sale. These cores are then sent off to WEB CAM and prepped, hardwelded and then grinded to our specifications and then delivered to the next customer. Aside from hardweld cams, another type of cam is a Billet Heat Treated cam, we do not use this process. This type of cam is relatively inexpensive to produce, and does not require a core (because you are purchasing a cam out right). Billet heat treated cams wear down much quicker (we have seen complete breakdown of a Heat treated billet cams in under 5000 miles!) and are not nearly as durable as hardweld cams. Because of that we only offer highest quality hardweld cams. Since we choose to only offer hardweld cams, during some seasons when many people are doing engine modifications, you may experience longer delays in receiving your order as we wait for cam core to be returned. But we figure that is better than waiting for a replacement for a failed cam or prematurely worn cam. Please call us regarding any further questions you may have.
V STAR 1100 FLAT SLIDE CARBURETORS
For years Keihin has be known as one of the top carburetor builders in the industry. And the Flat Slide style carb is one of the most responsive style of carburetor made by any company. These carbs are so advanced, when our competition first purchased them from us (yes you read that right) to put on their V-Star 1100, they complained these things are junk, sold them, and put the stock carburetors back on. Well interestingly enough they now only sell the EXACT same carburetors they purchased from us that he initially called "junk". Well, obviously the carbs didn't change, maybe he just learned (oh yeah, and bought a second set!).
Keihin carbs are used by race bike manufacturers all over the world, and we spent allot of time designing them to fit on the 1100 engine. The stock V-Star 1100 comes with CV (or constant velocity) carburetors. These carbs have no direct connection with your hand to the slide. The slide in the stock carburetor is pulled up using vacuum created by the engine. CV carbs were basically designed to be very easy to tune on a mass production scale. As you can figure, this style of carburetor generates very sluggish acceleration. For example, when you give the throttle a full twist, the slides do not come up, until the engine creates enough force to pull them up. Only then after that delay do you finally begin to get response.
On the contrary, with the Keihin FCR carbs, the slide is directly connected to the throttle cable, which means when you give the throttle a twist, you get instantaneous throttle response, anywhere from partial to full "hold on to the grips" throttle. In addition the carbs we offer are 39 mm as opposed to the 37 mm stock setup. This allow the engine to obviously pull more air and fuel in when requested. The main benefit from these carbs is advancing and increasing the performance power band in the normal driving range. Although overall hp will increase 7 hp +/- over the stock carbs, actual power of the engine in normal driving rpm ranges will be even more significantly increased. Another benefit is increased gas mileage when touring. People that install the carbs notice that gas mileage goes up, unless of course your throttle happy, and then all bets are off!! Furthermore when packaged together with the rest of our performance products, hang on!!! These carbs have almost limitless adjustability, with a large range of available adjustable needles and jets for the ability to fine tune your engine to perfection. Please call us regarding any further questions you may have.
V STAR 1100 DYNA 3000 IGNITION
In 2004 Yamaha changed their V-Star 1100 ignition setup in some models. Mostly the California models. But some of the changed models appeared randomly elsewhere across the country. In 2005 the remainder of the states changed to the new version. The change was from a 2 plug setup to a 1 plug setup (the actual function of the box basically remain virtually unchanged). To verify which Dyna 3000 ignition will work for you, simply remove your drivers seat. The ignition module is right underneath it. If your stock module has 2 separate sets of wires that plug into the module with 2 plugs (as the picture shows) you will need the Dyna 3000. If it has only one wire plug set, you will need the Dyna 3000 Single Plug (V2).
Modern motorcycle cylinders are Nickel Ceramic plated. This precision process allows much better heat dissipation and much tighter bore tolerances (from less heat expansion and contraction) than the older method of steel sleeving a cylinder. In addition, Nickel Ceramic plating is much harder than a steel sleeve (its common to cylinders with 70,000 or more miles that still show the original hone "cross hatching" in them!). When over boring or repairing a compromised cylinder, re boring or repairing involved "sleeving" a cylinder with steel, and then boring the steel sleeve to the proper spec. This often led to over heating problems as a result since the steel sleeve now created a barrier between the piston and the cooling fins of the engine. Over time this robs your engine's performance and worse, compromises it's longevity.
Our process of Re-plating your cylinders ensures your engine is performing with maximum precision, reliability and longevity with all the benefits of a Nickel Ceramic cylinder.
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