Friday, December 25, 2020
Sunday, August 16, 2020
Corner Exit 3:57
3:42 Corner Exit (GS800)
4:07 Corner Exit (GS800)
3:48 Corner Exit (Cruiser)
2:59 Corner Exit (Cruiser)
3:57 Corner Exit (R1)
5:26 Corner Exit (R1)
Sunday, January 1, 2012
Saturday, May 14, 2011
How your suspension works! - ThumperTalk
How your suspension works! - ThumperTalk
Here is an awesome write-up from a Showa engineer on how mx suspension works, enjoy its pretty good stuff!
As the damper or shock is compressed a rod is pushed into the damper body. At the end of this rod is a piston that gets forced through oil that is contained within the damper. The oil is then forced through ports in the piston. When the shock is compressed the oil flows through the compression ports. When the shock returns to the extended position oil flows in the opposite direction through the rebound ports. The direction that the oil flows through these ports is determined by the bending valve shims that are located on either side of the piston. They create a check valve on either side of the piston and keep the oil from flowing in both directions in the ports. When the shock is compressed the oil forces the rebound shims against the surface of the piston and blocks off the rebound ports. At the same time the oil bends back the compression shims from the surface of the piston and flows through the compression ports. This process is reversed as the shock returns to its extended length. The damping force that the shock produces at different piston velocities in either direction is determined by oil viscosity and the diameter, thickness & number of these valve shims.
A certain amount of oil is also allowed to bypass the piston during compression & rebound as well. There is a small port at the end of the rod that leads to just below the compression valve stack. The size of this port, and how much oil can flow through it, is controlled by a tapered needle that runs through the center of the rod. A screw near the bottom of the rod controls the position of the needle. This screw is known as the rebound adjuster. In this system this screw will affect compression and rebound oil flow. However it is still called a rebound adjuster screw because it has a much larger effect on the rebound than on the compression. Some systems have a check valve in this circuit as well and only allow oil to flow during rebound. However the check valve design has a slow response to small repetitive bumps (like the wash board effect that can develop on fire roads) and is not usually used. The rebound adjust is used to control how quickly the shock returns to its extended length. Turning the screw in makes it return slower and turning it out quicker. The rebound screw should be adjusted out enough so that the rear wheel can follow the contours of the terrain. However not so far out that the rear wheel feels like it is springing back and wanting to throw the rider over the bars after a bump or jump.
As the rod enters the damper body its volume displaces the oil in the shock. This displaced oil must go somewhere so it flows into the shock reservoir. The shock reservoir contains a sliding piston or a bladder. The piston or bladder separates a high pressure gas, usually nitrogen, from the oil. As the oil flows into the reservoir it compresses this gas even more. The gas is separated from the oil to keep it from mixing with the oil and causing the oil to foam. If the oil were to foam the damping would decrease and be difficult to control. The shock is kept under high pressure to keep the oil from reaching its vapor pressure and cavitating as it flows from one side of the piston to the other. Cavitation is when the oil begins to vaporize or boil. This happens when its pressure becomes too low. If the oil was to cavitate this once again would severely affect damping. Before the oil enters the reservoir it must flow through an orifice that separates the reservoir from the shock body. Once again the size of this hole is controlled by a tapered needle connected to a screw. This screw is called the low speed compression adjuster. Turning the screw in and out controls the cross-sectional area of the orifice. Turning the screw out increases the area that the oil can flow through. This allows more oil to flow quicker into the reservoir and keeps the pressure lower in the shock. Lower internal shock pressure means that there is less damping force acting against the rod as it tries to enter the shock body. By adjusting the low speed compression adjuster the way the shock reacts to small bumps and lower speed events (Such as G-outs) can be manipulated.
Some higher end shocks also have a high speed compression adjustment as well. This adjustment allows the user to adjust the way the shock reacts during a high speed event. A good example of this type of event would be hitting a square curb while riding fast. The high speed compression system works by allowing oil displaced by the rod to bypass the slow speed compression adjuster. Turning the high speed adjuster in and out controls the amount of preload that is placed on a heavy spring inside of the adjuster. The spring forces a valve closed and oil is not able to travel through the high speed circuit. All of the oil displaced by the rod must travel through the slow speed compression circuit. However the quicker the shock is compressed the higher the internal pressure gets. When the pressure gets high enough to overcome this spring the valve cracks opens and oil can go through. By properly manipulating the high speed compression adjuster how stiff the shock feels during a high speed event can be controlled.
Another important adjustment that is often over looked is the main spring preload. The way the bike handles and turns is greatly affected by this adjustment. Correctly adjusting preload is quick and easy as well.
The shock spring preload is adjusted by rotating the spring preload adjuster at the top of the spring. For a proper setup the bike should sag approximately 33% of the rear wheel’s total travel when the rider is seated on it. So if the bike has 6 inches of travel at the rear wheel it should sag approximately 2 inches with the rider seated on it. If the bike is sagging more than this then the preload adjuster should be turned clock wise to add more preload to the spring. Be careful that the spring preload adjuster is not turned down so far that the spring reaches solid height before the shock travels through its entire stroke. If proper sag can’t be achieved without this happening then the spring rate is too soft and you need to go to a higher one. On the other hand if the bike is not sagging enough, even with the preload adjuster almost completely loose, then the spring rate is too high. To properly measure the sag it is usually easiest to get two friends to help. While you are seated on the bike have one person hold you upright while the other takes the measurement. The measurement should be taken from the rear axle to some point vertically above the axle. The fork should also sag 33% of their travel with the rider aboard. However many forks do not have a preload adjuster. You can get around this buy adding washers with the same OD as the fork springs between the spring and the fork cap. You need to be careful that you do not add too many shims and cause the springs to reach solid height before the fork can go through its entire travel. Once again if you can not achieve the proper sag with your current springs you will need to go up or down with the spring rate. When measuring the sag in the front use the same procedure as the rear only this time measure along the axis of the fork.
Here is an awesome write-up from a Showa engineer on how mx suspension works, enjoy its pretty good stuff!
As the damper or shock is compressed a rod is pushed into the damper body. At the end of this rod is a piston that gets forced through oil that is contained within the damper. The oil is then forced through ports in the piston. When the shock is compressed the oil flows through the compression ports. When the shock returns to the extended position oil flows in the opposite direction through the rebound ports. The direction that the oil flows through these ports is determined by the bending valve shims that are located on either side of the piston. They create a check valve on either side of the piston and keep the oil from flowing in both directions in the ports. When the shock is compressed the oil forces the rebound shims against the surface of the piston and blocks off the rebound ports. At the same time the oil bends back the compression shims from the surface of the piston and flows through the compression ports. This process is reversed as the shock returns to its extended length. The damping force that the shock produces at different piston velocities in either direction is determined by oil viscosity and the diameter, thickness & number of these valve shims.
A certain amount of oil is also allowed to bypass the piston during compression & rebound as well. There is a small port at the end of the rod that leads to just below the compression valve stack. The size of this port, and how much oil can flow through it, is controlled by a tapered needle that runs through the center of the rod. A screw near the bottom of the rod controls the position of the needle. This screw is known as the rebound adjuster. In this system this screw will affect compression and rebound oil flow. However it is still called a rebound adjuster screw because it has a much larger effect on the rebound than on the compression. Some systems have a check valve in this circuit as well and only allow oil to flow during rebound. However the check valve design has a slow response to small repetitive bumps (like the wash board effect that can develop on fire roads) and is not usually used. The rebound adjust is used to control how quickly the shock returns to its extended length. Turning the screw in makes it return slower and turning it out quicker. The rebound screw should be adjusted out enough so that the rear wheel can follow the contours of the terrain. However not so far out that the rear wheel feels like it is springing back and wanting to throw the rider over the bars after a bump or jump.
As the rod enters the damper body its volume displaces the oil in the shock. This displaced oil must go somewhere so it flows into the shock reservoir. The shock reservoir contains a sliding piston or a bladder. The piston or bladder separates a high pressure gas, usually nitrogen, from the oil. As the oil flows into the reservoir it compresses this gas even more. The gas is separated from the oil to keep it from mixing with the oil and causing the oil to foam. If the oil were to foam the damping would decrease and be difficult to control. The shock is kept under high pressure to keep the oil from reaching its vapor pressure and cavitating as it flows from one side of the piston to the other. Cavitation is when the oil begins to vaporize or boil. This happens when its pressure becomes too low. If the oil was to cavitate this once again would severely affect damping. Before the oil enters the reservoir it must flow through an orifice that separates the reservoir from the shock body. Once again the size of this hole is controlled by a tapered needle connected to a screw. This screw is called the low speed compression adjuster. Turning the screw in and out controls the cross-sectional area of the orifice. Turning the screw out increases the area that the oil can flow through. This allows more oil to flow quicker into the reservoir and keeps the pressure lower in the shock. Lower internal shock pressure means that there is less damping force acting against the rod as it tries to enter the shock body. By adjusting the low speed compression adjuster the way the shock reacts to small bumps and lower speed events (Such as G-outs) can be manipulated.
Some higher end shocks also have a high speed compression adjustment as well. This adjustment allows the user to adjust the way the shock reacts during a high speed event. A good example of this type of event would be hitting a square curb while riding fast. The high speed compression system works by allowing oil displaced by the rod to bypass the slow speed compression adjuster. Turning the high speed adjuster in and out controls the amount of preload that is placed on a heavy spring inside of the adjuster. The spring forces a valve closed and oil is not able to travel through the high speed circuit. All of the oil displaced by the rod must travel through the slow speed compression circuit. However the quicker the shock is compressed the higher the internal pressure gets. When the pressure gets high enough to overcome this spring the valve cracks opens and oil can go through. By properly manipulating the high speed compression adjuster how stiff the shock feels during a high speed event can be controlled.
Another important adjustment that is often over looked is the main spring preload. The way the bike handles and turns is greatly affected by this adjustment. Correctly adjusting preload is quick and easy as well.
The shock spring preload is adjusted by rotating the spring preload adjuster at the top of the spring. For a proper setup the bike should sag approximately 33% of the rear wheel’s total travel when the rider is seated on it. So if the bike has 6 inches of travel at the rear wheel it should sag approximately 2 inches with the rider seated on it. If the bike is sagging more than this then the preload adjuster should be turned clock wise to add more preload to the spring. Be careful that the spring preload adjuster is not turned down so far that the spring reaches solid height before the shock travels through its entire stroke. If proper sag can’t be achieved without this happening then the spring rate is too soft and you need to go to a higher one. On the other hand if the bike is not sagging enough, even with the preload adjuster almost completely loose, then the spring rate is too high. To properly measure the sag it is usually easiest to get two friends to help. While you are seated on the bike have one person hold you upright while the other takes the measurement. The measurement should be taken from the rear axle to some point vertically above the axle. The fork should also sag 33% of their travel with the rider aboard. However many forks do not have a preload adjuster. You can get around this buy adding washers with the same OD as the fork springs between the spring and the fork cap. You need to be careful that you do not add too many shims and cause the springs to reach solid height before the fork can go through its entire travel. Once again if you can not achieve the proper sag with your current springs you will need to go up or down with the spring rate. When measuring the sag in the front use the same procedure as the rear only this time measure along the axis of the fork.
Wednesday, April 6, 2011
Wednesday, March 30, 2011
J's roll-center adjuster - Page 4 - Honda-Tech
thoughts on j's roll-center adjuster - Page 4 - Honda-Tech
Roll center adjusters from J's, they should be plenty strong. The load on the ball joint will decrease, while the load on the steering knuckle, where the ball joint is pressed in will increase. The knuckles generally have enough strength so that this is not a problem.
Roll center adjusters from J's, they should be plenty strong. The load on the ball joint will decrease, while the load on the steering knuckle, where the ball joint is pressed in will increase. The knuckles generally have enough strength so that this is not a problem.
Wednesday, March 2, 2011
AE: Honda's race-bred connecting rod bearing
AE: Honda's race-bred connecting rod bearing
Stroking of the 1.6-L engine by 19% to obtain 1.8-L would have been accompanied by a 20% increase in load of such vital components as the crankshaft. Our data on the 1.6-L's crankshaft indicated that it would not stand up to that kind of load. Nor would the connecting-rod bearing metal." Widening the bearing metal would have made it withstand the load, but that would have further reduced the crankshaft's strength, which had to accommodate the wider bearings within a set length. Attainable and allowable piston speed is really determined by the fine balance between the crankshaft and connecting-rod bearing performances
In the B18C, it enabled the engine designers to reduce the connecting-rod bearing width from the B16A's 19.5 to 17.5 mm. Two millimeters shaved off each connecting rod journal is added to the crankshaft webs flanking it, giving the crankshaft the extra strength it needed
Stroking of the 1.6-L engine by 19% to obtain 1.8-L would have been accompanied by a 20% increase in load of such vital components as the crankshaft. Our data on the 1.6-L's crankshaft indicated that it would not stand up to that kind of load. Nor would the connecting-rod bearing metal." Widening the bearing metal would have made it withstand the load, but that would have further reduced the crankshaft's strength, which had to accommodate the wider bearings within a set length. Attainable and allowable piston speed is really determined by the fine balance between the crankshaft and connecting-rod bearing performances
In the B18C, it enabled the engine designers to reduce the connecting-rod bearing width from the B16A's 19.5 to 17.5 mm. Two millimeters shaved off each connecting rod journal is added to the crankshaft webs flanking it, giving the crankshaft the extra strength it needed
Tuesday, March 1, 2011
Balance shaft - Secondary Balance
Balance shaft
Balance shafts are most common in inline four cylinder engines which, due to the asymmetry of their design, have an inherent second order vibration (vibrating at twice the engine RPM) which, contrary to popular belief, cannot be eliminated no matter how well the internal components are balanced. This vibration is generated because the movement of the connecting rods in an inline engine is not symmetrical throughout the crankshaft rotation; thus during a given period of crankshaft rotation, the descending and ascending pistons are not always completely opposed in their acceleration, giving rise to a net vertical inertial force twice in each revolution whose intensity increases quadratically with RPM, no matter how closely the components are matched for weight.[2]
The problem increases with larger engine displacement, since the only ways to achieve larger displacement are with a longer piston stroke, increasing the difference in acceleration, or by a larger bore, increasing the mass of the pistons; either way, the magnitude of the inertial vibration increases. For many years, two litres was viewed as the 'unofficial' displacement limit for a production inline four-cylinder engine with acceptable NVH characteristics.
The basic concept behind balance shafts has existed since 1904, when it was invented and patented by British engineer Frederick Lanchester. Two balance shafts rotate in opposite directions at twice engine speed. Equally sized eccentric weights on these shafts are sized and phased so that the inertial reaction to their counter-rotation cancels out in the horizontal plane, but adds in the vertical plane, giving a net force equal to but 180 degrees out of phase with the undesired second-order vibration of the basic engine, thereby cancelling it. The actual implementation of the concept, however, is concrete enough to be patented. The basic problem presented by the concept is adequately supporting and lubricating a part rotating at twice engine speed at the higher RPMs where the second order vibration becomes unacceptable.
There is some debate as to how much power the twin balance shafts cost the engine. The basic figure given is usually around 15 hp (11 kW), but this may be excessive for pure friction losses. It is possible that this is a miscalculation derived from the common use of an inertial dynamometer, which calculates power from angular acceleration rather than actual measurement of steady state torque. The 15 hp (11 kW), then, includes both the actual frictional loss as well as the increase in angular inertia of the rapidly rotating shafts, which would not be a factor at steady speed. Nevertheless, some owners modify their engines by removing the balance shafts, both to reclaim some of this power and to reduce complexity and potential areas of breakage for high performance and racing use, as it is commonly (but falsely) believed that the smoothness provided by the balance shafts can be attained after their removal by careful balancing of the reciprocating components of the engine.[citation needed]
Balance shafts are most common in inline four cylinder engines which, due to the asymmetry of their design, have an inherent second order vibration (vibrating at twice the engine RPM) which, contrary to popular belief, cannot be eliminated no matter how well the internal components are balanced. This vibration is generated because the movement of the connecting rods in an inline engine is not symmetrical throughout the crankshaft rotation; thus during a given period of crankshaft rotation, the descending and ascending pistons are not always completely opposed in their acceleration, giving rise to a net vertical inertial force twice in each revolution whose intensity increases quadratically with RPM, no matter how closely the components are matched for weight.[2]
The problem increases with larger engine displacement, since the only ways to achieve larger displacement are with a longer piston stroke, increasing the difference in acceleration, or by a larger bore, increasing the mass of the pistons; either way, the magnitude of the inertial vibration increases. For many years, two litres was viewed as the 'unofficial' displacement limit for a production inline four-cylinder engine with acceptable NVH characteristics.
The basic concept behind balance shafts has existed since 1904, when it was invented and patented by British engineer Frederick Lanchester. Two balance shafts rotate in opposite directions at twice engine speed. Equally sized eccentric weights on these shafts are sized and phased so that the inertial reaction to their counter-rotation cancels out in the horizontal plane, but adds in the vertical plane, giving a net force equal to but 180 degrees out of phase with the undesired second-order vibration of the basic engine, thereby cancelling it. The actual implementation of the concept, however, is concrete enough to be patented. The basic problem presented by the concept is adequately supporting and lubricating a part rotating at twice engine speed at the higher RPMs where the second order vibration becomes unacceptable.
There is some debate as to how much power the twin balance shafts cost the engine. The basic figure given is usually around 15 hp (11 kW), but this may be excessive for pure friction losses. It is possible that this is a miscalculation derived from the common use of an inertial dynamometer, which calculates power from angular acceleration rather than actual measurement of steady state torque. The 15 hp (11 kW), then, includes both the actual frictional loss as well as the increase in angular inertia of the rapidly rotating shafts, which would not be a factor at steady speed. Nevertheless, some owners modify their engines by removing the balance shafts, both to reclaim some of this power and to reduce complexity and potential areas of breakage for high performance and racing use, as it is commonly (but falsely) believed that the smoothness provided by the balance shafts can be attained after their removal by careful balancing of the reciprocating components of the engine.[citation needed]
Sunday, February 27, 2011
Saturday, February 26, 2011
Thursday, February 24, 2011
Top 5 Reasons an MBA is a Bad Investment | BNET
Top 5 Reasons an MBA is a Bad Investment | BNET
For years, an MBA degree has been seen as a first-class ticket to the management fast track. People spend $100,000 (or more!) to earn the degree, confident that it will propel their career into overdrive.
Even so, the once-golden MBA is quickly losing its luster. Let’s face it: the degree has been WAY over-hyped, MBA curricula are out of touch with real-world demands, and many programs have a culture that fosters some awful management habits.
With that in mind, here are the top five reasons your MBA may not be worth the money you’ll pay for it.
For years, an MBA degree has been seen as a first-class ticket to the management fast track. People spend $100,000 (or more!) to earn the degree, confident that it will propel their career into overdrive.
Even so, the once-golden MBA is quickly losing its luster. Let’s face it: the degree has been WAY over-hyped, MBA curricula are out of touch with real-world demands, and many programs have a culture that fosters some awful management habits.
With that in mind, here are the top five reasons your MBA may not be worth the money you’ll pay for it.
Wednesday, February 23, 2011
Main Oil Gallery
In the picture above, we've enlarged and polished the oil feed passage (A) by .250" from the front of the block all the way to the oil filter housing. The main oil galley (B) has also been polished internally, and the water pump housing (C) has been thoroughly deburred
Monday, December 27, 2010
Thursday, December 23, 2010
Exhaust Gas Analysis
CO2 - Carbon dioxide: This is the relative efficiency of the burn from complete combustion of the fuel. At all engine speeds, the best power will generally be found within less than a 0.3% change.
O2 - Oxygen: If the percentage is high, it indicates that more ignition advance can likely be used, or that the different cylinder offsets/staggers need correction due to a lean condition in one cylinder.
CO - Carbon monoxide: Mixture strength from partially burned fuel. If a given throttle position makes best power at a given percentage. All other throttle positions will be very close to this reading at best power.
HC - Total hydrocarbons in parts per million: Unburned fuel - Shows general state of engine health with lower readings for good large bore engines, and higher readings for good small bore engines.
NOx - Nitrogen Oxides in parts per million: High readings indicate high combustion temperatures and can be a precursor to detonation. Among many things, this hydrocarbon count indicates compression and squish/quench conditions, as well as spark strength and combustion dynamics
O2 - Oxygen: If the percentage is high, it indicates that more ignition advance can likely be used, or that the different cylinder offsets/staggers need correction due to a lean condition in one cylinder.
CO - Carbon monoxide: Mixture strength from partially burned fuel. If a given throttle position makes best power at a given percentage. All other throttle positions will be very close to this reading at best power.
HC - Total hydrocarbons in parts per million: Unburned fuel - Shows general state of engine health with lower readings for good large bore engines, and higher readings for good small bore engines.
NOx - Nitrogen Oxides in parts per million: High readings indicate high combustion temperatures and can be a precursor to detonation. Among many things, this hydrocarbon count indicates compression and squish/quench conditions, as well as spark strength and combustion dynamics
Exhaust Gas Analysis - Ignition Timing
I see this more often than I want. Mosty when a customer comes in with the latest and greates cams that are poorly matched to their engine combination. More is not better. More cam duration requires more static compression, or dynamic compression drops. A less efficient and lazy engine is the result. Even if peak power increases, the engine takes longer to rev to the same engine speed, resulting in a slower combination.
Choose to keep the cam(s) and increase compression, or change cam(s). Higher octane fuel doesn't help. You might try running a fuel with faster burn characteristics and working with cam timing as a band-aid fix to poor cam selection. But it is not the best answer.
O2 and CO2 levels will tell you a good bit about ignition advance - especially when more is needed or the fuel is way off. No specific numbers, as each engine combination and mapping alter combustion efficiency. But the ratio of both gases can indicate a lot until you get a good grasp on a particular engine combination.
THC goes up with poor combustion, as does carbon particulates (soot).
Fuels with too slow burn rate for needs, as well as poor vaporization, atomization and homoginization, will all require richer fuel mixtures - increasing CO% required for best output. But you can go too far with all of these as well. Great BSFC and response, but limited output due to fuel vapor displacing air.
NOx will provide a lot of info on ignition advance limitations and knock limits prior to the onset of detonation in knock-limited combinations.
I have putting together more information on gas analysis over the past few months, but it will take a few months to get back to it. We are in the middle of moving into a new facility. I will post up when it is complete.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss
Choose to keep the cam(s) and increase compression, or change cam(s). Higher octane fuel doesn't help. You might try running a fuel with faster burn characteristics and working with cam timing as a band-aid fix to poor cam selection. But it is not the best answer.
O2 and CO2 levels will tell you a good bit about ignition advance - especially when more is needed or the fuel is way off. No specific numbers, as each engine combination and mapping alter combustion efficiency. But the ratio of both gases can indicate a lot until you get a good grasp on a particular engine combination.
THC goes up with poor combustion, as does carbon particulates (soot).
Fuels with too slow burn rate for needs, as well as poor vaporization, atomization and homoginization, will all require richer fuel mixtures - increasing CO% required for best output. But you can go too far with all of these as well. Great BSFC and response, but limited output due to fuel vapor displacing air.
NOx will provide a lot of info on ignition advance limitations and knock limits prior to the onset of detonation in knock-limited combinations.
I have putting together more information on gas analysis over the past few months, but it will take a few months to get back to it. We are in the middle of moving into a new facility. I will post up when it is complete.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss
Subscribe to:
Posts (Atom)