Installing a Carburetor Jet Kit / Cleaning Carburetors / Synchronizing Carburetors
Installing new Steering Stem bearings
Installing new Spark Plugs / Fogging Cylinders
Mounting new Tires
Cleaning Brake Caliper Pistons
Repairing Damaged Crankcase
Assembling an Engine and Transmission
Installing a new Stator Coil
Changing Chain and Sprockets
Nitrous Oxide Injection Project
Installing a Carburetor Jet Kit
Carburetors facing up (like they do while sitting on the engine)
Carburetors turned over, showing side that faces intake ports
Float bowls (still attached to carburetors)
Drilling out the aluminum plug that covers the idle mixture screw (be careful not to hit the mixture screw underneath!)
Screw to remove the plug after it is drilled. I had to file off the tip of the screw, because it would hit the mixture screw before the threads would bite the plug.
The plug removed, showing the top of the idle mixture screw. I recommend doing this before you install the rest of the jet kit, because aluminum shavings get everywhere. You'll be disassembling the carbs anyway to clean them and install the jet kit, so doing this first makes sense.
The little plugs. Just throw them out, as you won't need them anymore. They do not function as a seal (the idle mixture screw has its own o-ring) - they are there because of EPA regulations. The idle mixture screws are pre-set at the factory to comply with emissions. The plug is there to prevent people from tampering with the idle-mixture screws. In countries other than the U.S., this plug is often not present. The factory setting is usually a very lean one, meant to reduce emissions. Changing the setting to slightly richer will not affect emissions a whole lot, but can make the engine more responsive off idle.
All four idle mixture screws removed. The little o-rings and washers often stick inside the carb, you need a tiny piece of wire to gently pull them out (so as to avoid losing them).
Idle screw with spring, washer, and o-ring. The spring keeps the o-ring sealed against the carb orifice, and also puts tension on the screw to prevent it from turning.
The vacuum-operated diaphragms are the black rubberish circular pieces. The green plastic piece holds the needles down inside them (not visible). The diaphragm covers and springs have been removed and are laying on the table above the carburetors.
The diaphragms, with their attached slides which hold the jet needle, have been removed.
Carburetors turned upside-down, showing float bowls. The hose in front (with the ziptie around it) is the gas line that feeds each carburetor. The hose in the rear, with 180 degree bend at the end, is a radiator coolant line. (Most carbs don't have the latter)
Float bowl has been removed; float and jets visible.
Jets and floats laid out on table.
Jets. The pilot jet is physically bigger than the main jet, but it's internal orifice is much smaller. The main jet, it's holder, and the holder mount, all thread together and thread into the carburetor. The main jet holder is deceiving. On many motorcycles with sidedraft CV carburetors this is basically a tube with holes in the side to aerate the gasoline as it gets sucked up into the bore of the carburetor. In such cases, the jet needle (operated by the diaphragms) slides up and down inside the needle jet (not shown) and the main jet holder. However, in downdraft carburetors (such as found on later-model sportbikes before fuel-injection became popular), the jet needle operates at a different angle from the jets. (see CVcarb.jpg) Hence, the main jet and it's holder mount into a passage which connects indirectly to the needle jet passage. The jet needle cap, shown in carb13float.jpg, caps off the orifice at the end of the needles' travel.
Diagram of how the two different kinds of emulsion tubes work. Diagram 1 is a main jet holder/emulsion tube from a sidedraft CV carburetor. Notice how the jet needle extends through the length of the tube. The small orifices in the side help mix air with the fuel; the air comes through the main air jet from the airbox side of the carburetor. Diagram 2 is a main jet holder/emulsion tube from a downdraft CV carburetor (which the R6 uses). Because the jet needle operates at a different angle from the emulsion tube (as mentioned previously), this emulsion tube is slightly different. It has two sets of lower orifices, with a deliberate blockage through the main passageway. This effectively forces the fuel to exit and re-enter the tube through the small orifices, atomizing it more effectively. The main air jet also helps with air/fuel mixture at the upper portion of the tube. While cleaning carburetors, make sure these orifices are clog-free. Also, a diagram of a pilot jet. Note how the orifice that meters the fuel through the pilot jet is in the middle of the brass body of the jet. This protects it from accidental blockage due to damage. (Imagine if that tiny orifice, which is fractions of a millimeter in diameter, were placed at the tip of the jet, merely dropping the jet may be enough force to smash the soft brass hole closed.) Also, notice the holes towards the end of the pilot jet. These have a similar function to those of the emulsion tubes. They help atomize the fuel and mix it with air.
Carburetors with jets removed
Velocity stacks removed from the intake side of the carburetors (which are upside-down).
Using compressed air to clean internal carburetor passages. Spray aerosol carburetor cleaner into each passage first, then watch to see if it shoots out all connected orifices when you blow compressed air through it. A rubber tip air gun is the best to get a good seal.
Blowing air through the idle mixture screw hole.
OEM Yamaha (Keihin) on right, Dynojet on left. Note clip spaces on top of Dynojet needle for adjustment. Also notice different taper. Most of Dynojet's research focuses on the development of these needles - as they affect the engine throughout most of the rev range.
Carburetors installed on motorcycle.
Vacuum / synchronization lines. Cylinders 1 and 3 are plugged together, and cylinders 2 and 4 are plugged together. These are what you would attach to your vacuum gauge / manometer / mercury gauge to synchronize the carburetors. The larger hose with clamps on it in the forefront is the fuel line to the carburetors.
Vacuum line plugs removed.
Motion Pro brand mercury vacuum gauges temporarily secured to bike.
Vacuum gauge lines connected to intake port vacuum lines. It is important to have a good connection seal, as an air leak would render vacuum readings meaningless. I used a few short pieces of vinyl tubing which fit tightly into the vacuum lines.
Auxiliary/temporary fuel bottle connected. You need this, as the fuel tank obviously has to be removed to have access to the carburetors. I used an old copy machine toner bottle and J-B Welded a plastic tube fitting to the bottom. (Hey, it was free..)
An inline fuel filter installed between the temporary fuel tank line and the supply line to the fuel pump. It's a good idea to use one - you don't want any little particulate matter getting into your fuel system.
The mercury vacuum gauges shown while the bike is running. Try to get them as close together as possible. You adjust the carburetor synchronization by turning the small spring-loaded screws on the shaft that opens all the throttle butterfly valves. On modern japanese inline four-cylinder motorcycle engine carburetors, there are three sync screws: (numbering left-to-right, viewed as if sitting on motorcycle) the middle screw (between carb 2 and 3) balances the left two carbs to the right two carbs. The left screw (between carbs 1 and 2) balances carb 1 to carb 2. The right screw (between carbs 3 and 4) balances carb 4 to carb 3. 1/16 of a turn is often all it takes - sometimes more, sometimes less. Adjust the screws to get the vacuum readings as close together as possible (the readings in the picture are as close as I could get them at idle - plus, the picture is deceiving: the mercury jumps up and down at idle, because the vacuum pulse only occurs when the cylinder is taking in air/fuel). When you open and close the throttle (slowly, lest you suck mercury through the gauge lines from high intake tract vacuum) the gauges should all rise and fall while remaining close together. If they are close together at idle, they will usually remain close together when you open the throttle. A carburetor synchronization should always be performed after installing a jet kit or cleaning carburetors. The engine will start easier, run smoother, have more power, and get better gas mileage once a synchronization is performed (versus an un-synched engine).
Installing new Steering Stem bearings
R6 shown with forks removed
Upper steering stem bearings. Original equipment ball bearings.
Lower steering stem bearings. OEM ball bearings.
Stem shown with All Balls brand tapered roller bearings pressed on.
Bearing after being lubed with grease. Don't just coat the bearing with grease - you need to work it into the bearing, continuously pushing it in. A bearing packer tool can help, but in this case I didn't use one.
New upper bearing race installed for tapered bearing. The old ball-bearing type races, once tapped out, make a great tool to tap in the new races, as they are exactly the right diameter.
Lower tapered bearing race installed.
Fogging Cylinders (for storage, and prior to seasonal startup)
Spraying fogging oil into the cylinders. I used a small 1/8" I.D. tube, and made sure it could feel it scrape past the spark plug hole threads and hit the top of the piston, ensuring that I was actually dispersing oil into the cylinder, not just the spark plug well. I did this every month during storage. Sure, the motorcycle smoked a whole bunch once I started it up in spring, but I'd rather have that versus rusted/corroded cylinder walls/rings. It only takes one good warm up cycle to rid the engine of the fogging oil anyway.
Installing new Spark Plugs
NKG CR10EK spark plugs. Old on top, new on bottom.
Old NGK CR10EK spark plugs with about 17,000 miles on them.
Using the plug wrench from the tool kit. It is narrow in diameter, and has a rubber fitting inside it to hold the spark plug while you're lowing into down into the well. If you do not have such a tool, and plan on using a deep-well socket to tighten the plug, first use a needle-nosed pliers or a hemostat to gently lower the spark plug down into the hole. Merely dropping it in may be enough force to bend the electrode, possibly shorting it completely.
The spark plug holding tool lowered into the spark plug well.
Using a 17 mm socket, a universal joint adapter, and a 12" extension to tighten the plug.
The stick-type ignition coils installed over the spark plugs.
Airbox installed. The loose wire is a battery maintainer. And yes, the crankcase breather is not connected yet - it blocks access to the synchronization tubes.
My custom license plate bracket. I simply used the OEM turn signals, and some pieces of 1/8" x 1" strap aluminum bent to shape, drilled, and mounted. Looks pretty tidy when the plate is on.
My custom made rearstand with swingarm spools/buttons (or whatever you want to call them). For about $15 worth of 3/4" square steel tubing, about 2 hours welding/grinding time, and a can of black epoxy spray paint, voila! The spools are 2" sections of 3/4" conduit with washers welded on the ends, ground all nice and smooth, and also spray-painted. The 3/4" square tubing is adequate to support the weight of the R6, which is a fairly light motorcycle. For anything bigger, I would recommend 1" square tubing or circular tubing. (And yes, those are snow shovels in the background.)
Mounting new Tires
Ok, so this isn't my R6. A bigger brother, the R1.
Rear wheel removed.
Coats RC-100 Pneumatic Rim clamp (with Electric Rotation) / Pneumatic Bead Breaker / Tire Changing Machine. Very handy, to say the least...
Using the pneumatic tire bead breaker. Careful not to scratch the wheel.
Using the No-Mar tire changing bar to bring the first bead of the tire over the rim of the wheel...
Using the No-Mar tire changing bar to bring the second bead of the tire over the rim of the wheel. Insert the bar, rotate the tip 90 degrees, then rotate the bar around the circumference of the wheel to remove the tire, using a separate bar through the axle hole as a pivot point.
Using the No-Mar tire changing bar to install a new tire onto the wheel. First, you insert the double-tipped end under the rim of the wheel, then...
... Rotate the bar around the circumference of the wheel, again using the separate bar through the axle hole as a pivot point. Note that the bead of the tire is pushed into the recessed portion of the wheel - the bead isn't seated, allowing you to install the tire.
The tire mounted on the wheel. Now what remains to be done: use compressed air to seat the beads and then inflate to proper pressure, balance the tire, then reinstall on the motorcycle. No-Mar products deliver as promised. If you use the vegetable-based lubricant they supply, removal/installation is slick. The HDPE (High Density PolyEthylene) tips do not scratch the wheels at all. They are relatively soft, though, and may have to be replaced fairly often. As an added bonus, when you buy one of their products, you get an instructional DVD video.
Cleaning Brake Caliper Pistons
Use an allen wrench to remove the bolts on the rear brake caliper. Note: the rear caliper on this R6 is a sliding-caliper type, meaning that pistons only push on one brake pad, and the whole caliper slides on these bolts to equalize the pressure on both brake pads. (The motorcycle is fairly dirty in these pictures - it had been ridden in the rain.)
As mentioned above, these are the bolts which the caliper slides on. A little dab of grease on each one before reinstallation is a good idea.
The rear caliper removed. Note how dirty everything is.
Rear caliper, brake pedal, and rear brake master cylinder and reservoir.
The rear brake pads will stay in place when you remove the rear caliper. Note that different models/makes of motorcycles have different kinds of calipers; the info here is specific to the 2001 R6.
The rear caliper pistons. To effectively clean them, they'll have to be extended.
To extend the pistons outward, pump the rear brake pedal slowly. Keep an eye on the fluid reservoir - do not let the fluid in the reservoir get so low you cannot see it. If one piston wants to come out, but the other sticks, use a c-clamp to hold the free one to force the other to come out.
Pistons extended, showing approximately 1/4" of clean metal. Don't extend the pistons too far - or they'll pop out of their seals, necessitating reinstallation and brake fluid bleeding.
A strip of emery cloth used to 'floss' the pistons. It looks like sandpaper, but DO NOT use sandpaper rougher than 1000 grit. 1000 grit is very fine; enough to remove gunk but smooth enough to polish metal without scratching it. Also, this length proved to be a bit short - cut a longer one.
Using the emery cloth to 'floss' the pistons. Make sure to clean around the entire circumference of each piston. Compressed air would also be handy to blow off the fine grit created by flossing.
The cleaned, 'flossed' pistons. Push both of them back in together, remount the caliper, and remember to pump up the brake pedal.
Removing the mounting bolts on the front caliper.
The brake pads, retaining pin and anti-chatter spring. Again, note that different models/makes of motorcycles have different kinds of calipers; the info here is specific to the 2001 R6.
Front caliper removed from fork tube and with pads removed.
Caliper turned upside down.
A piece of aluminum (in this case an aluminum tire lever) inserted between the pistons. Pump the front brake lever to move the pistons out. Again, do not let the fluid in the reservoir drop out of sight.
'Flossing' the pistons on the front brake caliper. Remember to blow off the resultant grit with compressed air.
Cleaned pistons, ready to be retracted and reinstalled. After the pads are reinstalled and the caliper is remounted - remember to pump-up the brake lever until it feels firm.
Repairing Damaged Crankcase
To make a long story short, the nut came off the end of the counter-shaft, wedged itself between the chain and the sprocket, which subsequently broke off a mounting tab on the crankcase, which exposed the transmission mainshaft, thus releasing a good bit of oil.
The broken crankcase, showing an exposed transmission bearing.
The sprocket retaining nut, which came off and wedged itself between the chain and sprocket.
The plastic sprocket cover/guard. A little mangled, but still usable.
The mounting tab which broke off the crankcase.
A zoomed-out view of the broken case.
The internal side of the broken tab.
The engine after being removed from the frame.
The separated crankcase.
I had a local blacksmith/welding shop weld the tab back onto the hole. (I cut the protruding mounting portion off to keep this from ever happening again.)
The weld, as viewed from inside the crankcase.
The weld after being ground down so the bearing can fit back in.
Assembling an Engine and Transmission
Engine with crankcase split apart, showing upper half of crankcase (upside-down) with crankshaft still in place. You can see the cam chain and the ignition timing rotor on the end of the crankshaft, and the output gear on the crankshaft, which meshes with the outer clutch hub (not installed when this picture was taken).
Using a torque wrench to tighten the bolts that hold the transmission main shaft bearing (clutch side) in place.
Close up of the transmission main shaft and the shift drum and one shift fork beneath and to the right. Note the oil pressure passages that feed oil to both mainshaft bearings.
Countershaft laid in place.
Close up of counter-shaft and the two other shift forks. Also, the neutral position indicator switch is visible protruding from the rear of the crankcase. A detent on the shift drum actuates the switch while in neutral.
Both crankcase halves laid out.
Crankcase halves viewed from the side. Note the seal on the countershaft. The countershaft sprocket installs on the end of that shaft. Care should be taken not to damage the seal while installing the crankcase halves.
Close of up upper crankcase half before assembly. Connecting rods and main bearings clearly visible from this view. Note the black RTV sealant applied to the crankcase mating surfaces prior to reassembly. Also, be sure to apply engine oil to the crankshaft journals and bearing inserts before reassembly.
Using a torque wrench to properly attach the lower crankcase half to the upper one.
Crank case halves assembled. (Engine upside-down) The large circular fitting on the front of the engine is where the oil-to-coolant heat exchanger is installed. The circular opening on the side of the engine is where the water pump shaft is mounted to be driven by the internal oil pump shaft (which in turn is driven by a chain running on a sprocket from behind the outer clutch hub).
Outer and inner clutch hub installed. Oil pan also installed.
Clutch plates installed. Note the metal band laying on the plastic bag, and the pressure plate and pull rod.
Metal band installed on outer clutch hub. I assume the purpose of the band is to prevent the centrifugal effect from stressing the aluminum tabs on the outer clutch hub.
Installing the pressure plate. Line up the dots on the pressure plate and the inner clutch hub. (Some mechanics and do-it-yourselfers have forgotten to do this step, with no ill effects. It would seem that perhaps the pressure plate and the inner clutch hub were balanced together, but since they are both cylindrically symmetrical, the importance of matching up the dots is in question. It's easy enough to do, though, so it's a good practice).
Pressure plate in place. Note pull rod with teeth. The clutch cable attaches to a shaft on the clutch cover which rotates a rod with teeth on it that pull on this shaft to disengage the clutch.
Clutch cover installed.
Valve cover removed, showing camshafts and sprockets (camshafts hidden underneath bearing cap).
Installing a new Stator Coil
Installing a new stator. New Electrosport brand stator on left, old one on right still installed in stator cover.
Obvious burned area on old stator. This caused a short on one of the phases of the stator, which dropped the net output voltage to the regulator. Subsequently, the battery kept discharging. I tested the regulator with a multimeter, and it tested OK. The short on the stator shirt showed up on the multimeter with a simple continuity test.
Stator cover and flywheel. Also note starter pinion and intermediate gear.
Old stator and new stator next to stator cover.
New stator installed in cover.
Stator cover installed on engine.
Changing Chain and Sprockets
Use a chisel or screwdriver to pry open the stake washer on the counter-shaft sprocket.
Use a metal rod wrapped in rags (or old towel) to prevent the wheel from spinning. The rod rests against the swingarm.
Remove the old nut using a breaker bar and socket.
Nut and old washer.
Sprocket with nut and washer removed.
If you loosen the rear axle adjusters enough, the chain will have enough slack to allow you to pull the chain up off the sprocket and remove the sprocket.
Old sprocket. Drive direction is counter-clockwise. Notice the hooking/wearing.
New RK 530 XSO Z1 chain, JT steel front and rear sprockets, and clip-type connecting link.
Instructions on back of RK chain box.
Note proper direction to install spring clip.
New chain (nice and shiny and greasy).
Grind off two rivets of old chain.
Rivets ground off, side plate ready to be pryed off. Also notice the "48" mark on the sprocket. It's always a good idea to not only look in the service manual for your sprocket size spec, but also positively identify the sprocket size on your motorcycle before ordering a new one.
Pry off the side plate with a flat blade screwdriver.
Pull the link out laterally.
New sprocket on wheel - note threadlocker on sprocket studs.
Wheel with new sprocket mounted on swingarm.
Old and new front sprocket. Compared with the new one, the old sprocket seems to be VERY worn, but the roller size is different on the old sprocket.
Installing new link. Be sure to put the o-rings on the pins before and after inserting the link through the bushings.
Using the RK mini chain press tool to press on the side plate of the connecting link.
Install the new countershaft sprocket using same method to prevent the rear wheel from turning, except with rod below swingarm this time.
Re-stake the splined stake washer. This (usually) prevents the nut from turning loose.
I double-staked the washer for good measure.
New chain and sprockets installed and tension adjusted.
Motorcycle completely reassembled!
Nitrous Oxide Injection Project
5 pound CO2 bottle with diptube (siphon) and brass valve.
Diptube bent to aim toward corner of bottle. (Allows extraction of all fluid when bottle is laying on an angle)
Valve installed on bottle. This is a CGA-320 type fitting (normal for CO2 use). The valve also incorporates a burst disc fitting, which is a small disc (not visible) of metal that covers a port in the valve. A hex type fitting is threaded over the disc, which crushes it into place, creating a seal. The thickness of the disc is calibrated to burst if the pressure in the bottle reaches a threshold value (3000 psi).
90-deg brass tube nitrous oxide injectors. (O.D. = 1/8 inch.)
Brass injectors fitted to intake port and secured with two-part epoxy.
Close up of injectors. The top one is for nitrous oxide, the second is for fuel, and the third is extra, possibly for water injection use.
Using a piece of 1/4" thick aluminum plate, I fashioned my own 90 degree fittings for 1/8" tube. Small size was important, thus I made my own.
18 little blanks of aluminum.
The fittings with 1/8" holes drilled half-way through, perpendicular to each other. Brass tee fittings shown in background.
The 1-into-4 distribution manifolds I constructed to split the nitrous oxide, fuel, and water lines to the four cylinders. I ended up only needing six of the 90-degree fittings, because I changed the design.
Injection tubes (1/8" O.D. nylon) leading to each cylinder intake port.
Manifold connected to injection tubes.
Zoom out. The whole injection system and solenoids hides underneath the carburetors (not installed).
Preliminary wiring circuit. More complex than normal, because I wired an arming switch to turn my horn button into a pulse button when the switch is on. Also, I wired in some LEDs to illuminate when the system is armed. The stainless steel braided nitrous oxide hose is visible in this picture as well.