[HONDA DAX 125] What is an engine bore-up? Easily increase maximum power output with a commercially available kit! Special Parts Takegawa proposes engine tuning techniques from the stock 123cc to 145cc | STEP 2 (Intermediate Level) - Motopeek - Latest Motorcycle News, Reviews & Updates

For engine tuning with a genuine 123cc displacement, see above for STEP:1 (Beginner’s Edition)!

“Bore-up” is the process of increasing the bore diameter of the piston and cylinder. This is a tuning technique that increases the intake volume of the air-fuel mixture and increases power.

Left: Normal. Middle: Bore-up, which increases displacement by enlarging the bore diameter of the piston and cylinder. Right: Bore and stroke-up, which increases displacement by enlarging the bore diameter of the piston and cylinder and lengthening the stroke length of the crankshaft.

“Bore-up” (illustration above), a standard method of tuning a motorcycle engine, involves increasing the outer diameter of the piston and the inner diameter of the cylinder, in other words, the bore diameter, to increase displacement.

This increases the amount of air-fuel mixture that can be taken in, resulting in increased power. The crankshaft that moves the piston up and down typically uses a standard type, or a type with the same size as the standard stroke.

In addition to increasing the bore diameter of the piston and cylinder, there is also a tuning technique called “bore and stroke up,” which involves replacing the crankshaft with an aftermarket part, lengthening the stroke length, and increasing the displacement.

Hyper S Stage Bore Up Kit 145cc… 179,300 yen (tax included) Part number: 01-05-5467

Compatible models: Dax 125 (JB04/JB06-1000001~)

The engine displacement has been increased from the stock 123cc to 145cc. By incorporating the parts listed below, you can achieve a significant power increase that surpasses not only the stock version but also the entry-level “Hyper Tuning Set (with big throttle body)”!

S Stage Bore Up Kit 145cc

By changing to a Φ54mm cylinder and Φ54mm piston (the stock is Φ50mm), the displacement has been increased from the stock 123cc to 145cc. By installing the FICON TYPE-X (injection controller) at the same time, it achieves torqueful output characteristics different from the stock.

The cylinder is made of aluminum with an iron sleeve. The bore diameter is 54mm, the stroke length is 63.1mm (standard), and the compression ratio is 11.2:1 (standard is 10.0:1).

The cylinder can be fitted with a special Takegawa M5 temperature sensor, so you can measure the cylinder temperature by purchasing a separately sold thermometer (compact LED thermometer with M5 temperature sensor).

※同キットは排気量が125cc以上になるため、原付二種登録では一般公道を走行することは不可
※競技専用品

Sports camshaft (N-10)

The “Sports Camshaft (N-20)” with different engine characteristics and ride feel is also available separately. Price: 21,780 yen (tax included), product number: 01-08-0191.

The optimal profile maximizes the performance of the stock cylinder head, improving output performance. By installing it on a stock engine, output at high rpm is also increased. By removing the decompression parts from the stock camshaft and installing it on a sports camshaft, it becomes an auto-decompression specification.

Big throttle body kit Φ34 (for stock cylinder head)

A unique big throttle body kit developed for Special Parts Takegawa engine parts. By adopting a Φ34mm big throttle body, the performance of Special Parts Takegawa engine parts is maximized, resulting in increased power output.

It can be compactly stored around the engine, and can be installed without ruining the silhouette of the vehicle. No modification of the cowl or wiring is required, and it can be installed with a bolt-on. An air filter with excellent intake efficiency is also included. *Cannot be used with a stock engine.

FI CON TYPE-X (injection controller)

This injection controller can be attached to the stock ECU via coupler-on. It comes with preset MAP settings to suit each engine specification. Simply select the MAP that matches the specifications of the bore-up kit or throttle body you are using on your smartphone or computer to complete basic operations and get ready to ride.

It is designed to be fully usable by even advanced users, allowing you to customize settings based on existing maps or create new maps. Connecting to a PC or smartphone while the engine is running allows for a convenient tachometer screen for easy settings. It also displays a throttle opening graph. Engine temperature monitoring is also possible. It also has a rev limit function. It can be installed simultaneously with the Honda genuine immobilizer alarm.

FIコン TYPE-Xをご使用の際には条件に適合したパソコンもしくはスマートフォンが必要になります。条件をご用意頂けない場合はご使用になれません。又、ソフトやアプリのダウンロードが必要になる為、インターネットに接続されている必要があります。
アプリの場合、有料となります。予めご了承下さい。

FIコン TYPE-X機能の詳細、条件は下記リンクボタンをクリックしてご確認下さい。
FIコン TYPE-X詳細ページはこちら

Large-capacity injector (G-1)

When equipped with an S-Stage Bore Up Kit 145cc, sports camshaft, FI-Con TYPE-X (injection controller), and big throttle body kit. The stock fuel injectors do not inject enough fuel to handle the increased intake air volume, so they are replaced with these large-capacity fuel injectors.