Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to build a kart racing engine [title] Have a clean, dry area to disassemble your engine. [title] Remove the stock exhaust from your engine. [step] You can get rid of it because you won't be needing it.

Ending1: In the middle of the engine where there are usually chunks of body, there will be an compartment which contains a rat wheel which has been removed. [substeps] For this method, take all the gears out of the engine, and place them in the compartment. Ending2: [title] Remove the carburetor from your engine. [step] You will not be able to use this either unless it is the flip-choke type with a screw-on air filter. Ending3: It is nice and clean because it has not been damaged or in need of cutting. [title] Remove the old fuel tank from your vehicle. Ending4: [title] Clean the inner compartment of your engine. [step] Find the tc2 (isopropyl) discharge chamber.

Answer format: ending1/ending2/ending3/ending4