best spinning bike for under 500 image
Jordan Wal
i want a bmx bike that wont take too much of a beating because i dont plan on using it on bike jumps but want something just to mess around on that will be easy to 180 on flatground and do huge bunny hops and bar spins. i am hoping someone can reccomend me a bike 20 pounds or lower and around 500. thanks alot
Answer
A light bike won't help you learn tricks, it will only make it easier to do tricks you already know how to do. A light bike won't compensate for poor technique.
That said, 20 lbs is way too light. ANY complete found that weighs 20 lbs will be very weak, and it would cost $1,800+ to get a custom bike to weigh under 20 lbs.
Here are the two best bikes you can get for around $500.
http://www.danscomp.com/products-BIKES-VERDE/102043/Verde_2012_Spectrum_Bike.html
http://www.danscomp.com/products-BIKES-WETHEPEOPLE/101996/We_The_People_2011_Trust_Bike.html
A light bike won't help you learn tricks, it will only make it easier to do tricks you already know how to do. A light bike won't compensate for poor technique.
That said, 20 lbs is way too light. ANY complete found that weighs 20 lbs will be very weak, and it would cost $1,800+ to get a custom bike to weigh under 20 lbs.
Here are the two best bikes you can get for around $500.
http://www.danscomp.com/products-BIKES-VERDE/102043/Verde_2012_Spectrum_Bike.html
http://www.danscomp.com/products-BIKES-WETHEPEOPLE/101996/We_The_People_2011_Trust_Bike.html
is ti possible to turbocharge a 03 zx-7r and if so what all is involved??????
bikerboy
what will I need to get and where??
Answer
Turbocharging is great when done correctly and a nightmare when not. There's several things to consider.
Turbo lag: that's the lag time between when you open the throttle and when the turbo gets to spinning enough that the engine starts making additional horsepower. With a turbo system that has a lot of lag, you whack open the throttle and then wait, wait and wait some more and then (usually) power comes on like flipping on a light switch, leaving you fighting to keep the bike under control.
Lag time is related to several things. A long distance between the exhaust port and the turbine contributes to long lag time as does a large turbo with heavy impellers. Because of inertia, heavy impellers take a long time to get spinning and a long time to slow down.
Turbine size: a turbo that's too big for your engine displacement gets in the way of air flow at low or no boost situations and will actually cut hp comapred to a naturally aspirated version of the same engine. A too-big turbo will build adequate boost only at high engine rpms.
A turbo that's too small will build boost quickly and at low rpms but without an exhaust wastegate, will quickly destroy itself because of excessive speed when you rev the engine up.
What you want is a turbo that's moderately sized for your engine displacement so it will have low lag, rev quickly, build boost at lower engine rpms but only use the wastegate at higher engine rpms. I thing the 1980's Kawasaki 750 turbo had an impeller about the size of a penny.
Putting more air into the engine increased the chance of detonation, hence the reason most turbo engines have a reduced comrpession ratio. For every half atmosphere (approx 7 psi), you need to lower the c.r. by 1 point. At low engine rpms with no boost, this decreases power, making turbo engines doggy at low speeds. To prevent detonation from destroying your engine under high boost, you need an automatic method of retarding the ignition.
Fuel can either be carb or fuel injection. With a carb ahead of the turbo, starting can be problematic and at low velocities, fuel can drop out of the airstream. With a carb after the turbo, you need a air tight box or enclosure the carb sets in, solid or foam floats to keep air pressure from crushing them, air tight linkage into the box and extra room for the box. You also must have a fuel pump that will produce more pressure than the turbo will produce. If not high enough, you get lean running and detonation or fuel starvation. If you have fuel injection, that simplifies things, but you'll need a boost sensor that will tell the ECU to provide more fuel.
You'll need extensive plumbing to get the exhaust to the turbo and back out as well as getting the pressurized air into the engine. You're also likely to have heat problems produced at the turbo and you may need to use head conserving measures for the exhaust between the engine and turbo. As the exhaust loses heat, it also loses velocity which decreases turbo efficiency.
You'll also need to get pressurized engine oil to the turbo and will surely need a good oil cooler. Lots of oil is needed to keep the turbo bearings cool and is why some are water cooled around the bearings. Some even use a separate oil reserviour to provide oil as a heat sink after shut down. Heat build up after shut down will carbonize the oil setting around the bearings and will damage them upon start up.
As you can see, it's not as simple as just bolting on a turbo and then going really fast. If you really want a turbo bike, look around for an '80s Honda (500-650 V twin) or 750 Kawasaki turbo. Of the two, the Kawasaki was the most civilized and fastest. The Yamaha and Suzuki turbo bikes were ok but are something better left for viewing instead of riding.
Turbocharging is great when done correctly and a nightmare when not. There's several things to consider.
Turbo lag: that's the lag time between when you open the throttle and when the turbo gets to spinning enough that the engine starts making additional horsepower. With a turbo system that has a lot of lag, you whack open the throttle and then wait, wait and wait some more and then (usually) power comes on like flipping on a light switch, leaving you fighting to keep the bike under control.
Lag time is related to several things. A long distance between the exhaust port and the turbine contributes to long lag time as does a large turbo with heavy impellers. Because of inertia, heavy impellers take a long time to get spinning and a long time to slow down.
Turbine size: a turbo that's too big for your engine displacement gets in the way of air flow at low or no boost situations and will actually cut hp comapred to a naturally aspirated version of the same engine. A too-big turbo will build adequate boost only at high engine rpms.
A turbo that's too small will build boost quickly and at low rpms but without an exhaust wastegate, will quickly destroy itself because of excessive speed when you rev the engine up.
What you want is a turbo that's moderately sized for your engine displacement so it will have low lag, rev quickly, build boost at lower engine rpms but only use the wastegate at higher engine rpms. I thing the 1980's Kawasaki 750 turbo had an impeller about the size of a penny.
Putting more air into the engine increased the chance of detonation, hence the reason most turbo engines have a reduced comrpession ratio. For every half atmosphere (approx 7 psi), you need to lower the c.r. by 1 point. At low engine rpms with no boost, this decreases power, making turbo engines doggy at low speeds. To prevent detonation from destroying your engine under high boost, you need an automatic method of retarding the ignition.
Fuel can either be carb or fuel injection. With a carb ahead of the turbo, starting can be problematic and at low velocities, fuel can drop out of the airstream. With a carb after the turbo, you need a air tight box or enclosure the carb sets in, solid or foam floats to keep air pressure from crushing them, air tight linkage into the box and extra room for the box. You also must have a fuel pump that will produce more pressure than the turbo will produce. If not high enough, you get lean running and detonation or fuel starvation. If you have fuel injection, that simplifies things, but you'll need a boost sensor that will tell the ECU to provide more fuel.
You'll need extensive plumbing to get the exhaust to the turbo and back out as well as getting the pressurized air into the engine. You're also likely to have heat problems produced at the turbo and you may need to use head conserving measures for the exhaust between the engine and turbo. As the exhaust loses heat, it also loses velocity which decreases turbo efficiency.
You'll also need to get pressurized engine oil to the turbo and will surely need a good oil cooler. Lots of oil is needed to keep the turbo bearings cool and is why some are water cooled around the bearings. Some even use a separate oil reserviour to provide oil as a heat sink after shut down. Heat build up after shut down will carbonize the oil setting around the bearings and will damage them upon start up.
As you can see, it's not as simple as just bolting on a turbo and then going really fast. If you really want a turbo bike, look around for an '80s Honda (500-650 V twin) or 750 Kawasaki turbo. Of the two, the Kawasaki was the most civilized and fastest. The Yamaha and Suzuki turbo bikes were ok but are something better left for viewing instead of riding.
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