What is meant by “Top-End” and “Bottom-End”?



Asked by: Joe Anot

Bottom end means the engine block, pistons, rings, connecting rods, crankshaft, etc. The top end is the cylinder head,valves, etc !

What is a bottom end?





Definition of ‘bottom end’
2. the bearing surface between the larger end of a connecting rod and the crankpin of the crankshaft.

What is considered top end?

Essentially the top-end is comprised of the cylinder head, or heads, with the valve train and the camshaft/s. We will break down the internal components of the cylinder head assembly, as well as explain two different cylinder head designs; the overhead valve and the overhead cam.

What is mean by top end in car?

of or relating to the best or most expensive products of their kind. a range of top-end vehicles.

What is bottom end of a motor?

engine block





The engine block – also known as a cylinder block – contains all of the major components that make up the bottom end of a motor. This is where the crankshaft spins, and the pistons move up and down in the cylinder bores, fired by the fuel combusting. On some engine designs, it also holds the camshaft.

What is top end in bike?

What is the Top End? The Top End is where the chemical energy of the fuel (gasoline) is converted into the kinetic energy that drives the motorcycle. The Top End contains two main parts, the engine head and the barrel.

What is top end bearing?

Top end bearing = Cross Head / Gudgeon Pin bearing. Bottom End Bearing / Crank pin bearing. Thrust Pad bearing. Pedestal bearing (generator alternator side insulated bearing)

What is bottom end performance?

1 Answers: Low end engine punch is a term frequently used to define a condition when the car performs a bit harder than it is usually meant to drive. It is a condition often faced in the case of low torque cars when the engine is unable to deliver the desired power at the top gear of the vehicle.

What is built bottom end?

This is the bottom half of an engine which has been strengthened. That is, the internal parts situated below the heads. Sometimes the engine block and internals are strengthened to better achieve top-level performance.



What is a bottom end bearing?

Bearings can be found in a number of locations across the engine: Cylinder Block/Bottom End. Main Bearing – Located on the Crankshaft Main journals. Big End Bearing – Located at the ‘Big End’ of the Connecting Rod, where it connects to the Crankshaft.

What is top end speed in bike?

If you think you’re ready, then read on to discover the world’s fastest bike.

  • 2017 MTT 420RR: 273 mph. …
  • 2000 MTT Y2K Superbike: 250 mph. …
  • 2021 Kawasaki Ninja H2R: 249 mph. …
  • 2020 Lightning LS-218: 218 mph.
  • 2021 Kawasaki Ninja H2: 209 mph. …
  • 2020 Ducati Panigale V4 R: 199 mph. …
  • 2020 Aprilia RSV4 1100 Factory: 199 mph.

How many hours is 450 top end?

Always having a clean air filter and fresh oil. What did the manual, service manual say? The 16 KX450 manual says 15 hours for a top end and the same for oil changes.



When should you replace top end on 4 stroke?

If you’re a regular racer, and especially if you’re riding a 250 four-stroke, then you’ll want to rebuild your new top-end between the 25-30 hour mark. If you’re riding a 450, or riding the bike under an easy load majority of the time, then you’ll want to rebuild the top-end between 30-40 hours.

How do I know if I need a top end rebuild?

When you see dirt in the intake, you’ll need to tear down the top end to check for damage. A damaged cylinder may need reconditioning or replating. The same goes for when you find your intake boot and airbox was not sealed properly. Anytime you find leaks, you’ll want to tear down and inspect for damage.

How do you know when you need a bottom end rebuild?

The bottom end of a dirt bike engine needs to be rebuilt when the rider has reached 80 hours of riding use or when they can’t get to the level of power they were before. Inspecting the spacing between the connecting rod, the crank shells, and crank webs will let the rider know when it’s time to replace those parts.

What does a top end rebuild consist of?

Top end rebuild means redoing just the heads. That means valve guides, check/replace valves and valve springs. Piston, cylinders, rings, crank bearings, etc.



Is it cheaper to rebuild or buy a new engine?

Rebuilding to repair is usually cheaper than buying a new engine, too. You may save up to half of the cost of a new engine by rebuilding. However, sometimes rebuilding is not a good option. In cases where rebuilding will cost as much as a new engine, your mechanic should be upfront about those costs.

How often should you do a top end rebuild?

It’s also important to keep in mind that if you’re running your two-stroke on the lean side, it may need more frequent rebuild intervals. When rebuilding the top end the general time frame is every 25 hours however like we said earlier every bike is unique and rebuild times also vary with engine sizes.