Recommendations When Put a large valve

Keteng side widened large piston to be installed. Go to the big valve fixer. Surely the average demand there is almost the same mechanics. In addition to the valve plug is big, there are some points that should be emphasized. The easiest example let us examine the output Kawahara cylinder head for Yamaha Mio The new head bobbed on request regular mechanic racing in Race Matic.

Recommended mechanical points are as follows:
1 Optimal Valve
Mechanical preferred because, already carrying the big valve. Namely the suction valve 28 mm and 23 mm exhaust. The optimum valve for down in 130 and 150cc classes.
Or can be paired with a block that is already filled piston 58,5mm. Because of the wide squish already setup 58,8mm. For the smaller piston receipts or greater re papas live in turner and set the width of squish.
2 Space Flexible Fuel
Another preferred feature of the mechanics of shape space fuel. Flexible contrived. This means that the volume of the combustion chamber can be reset. In accordance with a desired compression ratio.
If you want lower compression, please baker eroded space. To be so bloated volume. Let receipts precision measuring burette when the head is installed. More clearly about the compression ratio please read the article on the right RPM.

Setting precision valve. No need sekir

3 Sides keteng widened
Consider the side surface facing the cam chain. Created width too so flexible. That is when it got a touch Bore up piston amount, quite haphazard use big, no need then patched argon welding.
Because if you use a standard head factory, if you use 63.5 mm pistons at the top of argon welding aluminum to be patched. If it is not patched, compression often leak into space cam.
4 Spark Plug Screw Length
Threaded plugs are also often a problem when we do a big bore up. That's because we widen and enlarge the combustion chamber. As a result of the combustion chamber ektsrem breathing, threaded plugs so the victim. Screw so live a little. Risky aka Selek easy. As a result of compression to leak or even a loose spark plug. So often weld mechanical dead spark plug hole with a thicker aluminum. Then punched again and was given a long hole and threaded.

Long threaded hole plugs. In order not to leak

Well, a good head screw holes already made ​​long. To spark plugs could receipts of Honda Karisma, Jupiter MX or Suzuki Satria F-150.
5. Cut Valve
Cutting action of the valve is often done when we put the valve width. Adjusted with the final result turner workmanship. In determining the size of the cut stem with a spring adjustable valve used.
If you still use a valve spring can be setup 30-31mm Mio length of the bottom surface of the valve boss. If the valve spring Japanese for short AHRS can 28-29mm. Do not forget the former cutting the valve stem must hardener.
6 Matches Hole IN / EX
After making big valve head we usually match the suction and exhaust holes. Large holes can suck 80-95% of the diameter of the valve. While 65-75% of the waste hole diameter suction hole. As a reference such as the original head. 24.5 mm and a hole in the exhaust 22,5mm.
7 Without Sekir
Sekir workmanship is simple but makes bete valve. If using advanced machining process, usually do not leak. As head of this artificial Kawahara BRT and immediately use. If the gas entered from the side of the valve is not leaking.