munivmotoblog – Ada yang pernah mendengar model engine DOHC overbore.. ini sudah lazim dan banyak digunakan untuk motor – motor high speed. Namun apa jadinya jika istilah DOHC nearly Square atau dalam bahasa sederhananya panjang bore x stroke sampir sama (hanya selisih 0,0000 sekian). Ada pasti sudah sangat hafal bahwa All new Honda CB150SF ini memiliki engine yang sangat berbeda dari gen sebelumnya. Berbeda memungkinkan output power dan karakterisitikpun berbeda. Namun apa daya jika perbedaan tersebut digunakan gimmick marketing guna menaikan pamor

DOHC lebih powerfull dari SOHC

Square Engine

An engine is described as a square engine when it has equal bore and stroke dimensions, giving a bore/stroke value of exactly 1:1.
An engine is described as over-square or short-stroke if its cylinders have a greater bore diameter than its stroke length – giving a ratio value of greater than 1:1. This configuration decreases the torque but allows the engines to run at higher speeds and in fact develop greater peak power. 
An engine is described as under square or long-stroke if its cylinders have a smaller bore (width, diameter) than its stroke (length of piston travel) – giving a ratio value of less than 1:1. This configuration increases the displacement and therefore the torque of the engine, but may reduce the peak speed at which it is safe to run.

Square, Over square and Under square are terms that describe the ratio of  it’s bore and stroke. Bore is the cylinder’s diameter, and Stroke is the piston’s travel from the very top, to the very bottom: square engine has the exact bore and stroke dimensions, undersquare is when the stroke length is longer than the bore, oversquare is when the bore is larger than the stroke length.

Bahasa mudahnya menggunakan logika matematika dasar, Jika X =….Maka Y= …. biar lebih jelas sob

Jika Ratio bore = stroke nya = Maka ini disebut square engine

Jika Ratio bore > stroke nya = Malka ini disebut overbore engine

Jika Ratio bore < stroke nya = Maka ini disebut overstroke engine

Spesifikasi Engine All New Honda Cb150R yang mempunyai bore x stroke 57.3 x 57.8 mm jika melihat konsep diatas adalah enginya square… bukan nearly square. Perumpamaan matematika apakah 57,3 x 57,8 adalah sama. Tentunya tidak !!! maka 57,8 lebih tinggi daripada 57,3 (walaupun dalam taraf perbedaan sangat kecil). Jadi engine all new ini DOCH yang gimana? sampean bisa compare dengan beberapa ukuran bore x stroke engine DOHC dibawah ini

Satria FU

Bore 62 mm, Stroke 48,8 mm.

Bore > stroke DOHC Overbore

Honda CBR150R Thailand

Bore 63.5 mm,  Stroke 47.2 mm

Bore > Stroke DOHC Overbore

All New Honda Honda CB150SF 2015

Bore 57.3 mm x Stroke 57.8 mm

Bore < Stroke DOHC Over square

Bagaimana karakternya? pasti effisiensi di bahan bakar namun jika anda berharap performa lebih maka sampean kudu oprek dulu. Karena karakternya bukan untuk ngebut sob.. Diameter x langkahnya SAMA. bukan masuk kategori genus DOHC Overbore like Satria FU, CBR150R Thailand dan Old CB150SF.

Monggo dikomentari lads….