2-stroke 34 (61%)
4-stroke 18 (32%)
both, the more the merrier 2 (3%)
none, i don’t like engines 1 (1%)
Votes received: 55

It seems that many chose 2-stroke as their favourite engine. This maybe due to 2-stroke have simpler design, lighter weight and more power.

Some also chose 4-stroke engine. Honda EX5, Yamaha Lagenda and Yamaha LC135 belong to this group of engine. 4-stroke produce less pollution and gives less noisy exhaust sound. One of my friend who owns LC135 tells me that he really loves the bike because he can cruise up to 140 km/h furiosly but still be almost silent.

There are two person who chose both engine as their favourite and only one person didn’t like engines. Hmm, I wonder why he/she visit this site then…

1. Use low-smoke 2T oil, like this one from Petronas; Petronas Sprinta 5000 2T 2-Stroke Full Synthetic.

2. Never mix different brand of 2T oil. For example, if you use Petronas Sprinta 5000, stick for it for the rest of the life of the bike. It is also okay if you stick with cheap 2T oil, as long as you don’t mix them up, you will get less smoke.

3. Adjust the 2T pump on your bike throttle cable. This will reduce the amount of the 2T that gets into the combustion, so you will get less smoke. Here you need to remember that when you reduce the amount of 2T oil that gets into your engine, you also minimise the lubricality of the engine. So, if you want to use your bike for heavy use (eg: racing), adjust the setting so that more 2T oil can be pumped to your engine.

4. Check, service and adjust your carburetor for maximum fuel and air mixture for combustion, as this one will make your combustion chamber cleaner and therefore produce less smoke.

5. Use your bike at optimum RPM. Your exhaust will form a resonance inside the exhaust chamber to produce back pressure and back pressure can give more fuel, air and 2T oil to be combusted back into the engine.

Any more idea? Share with us in the comments section.

Why do you need to use racing chamber exhaust?

The basic idea behind an expansion chamber is to use the momentum and pressure of the exhaust gases to create a pump that squeezes more air and fuel into the cylinder during the intake stroke. It does the same sort of thing that a turbocharger does, but it does it without moving parts.

If you have read How Two-stroke Engines Work, then you know that the exhaust and intake parts of the cycle overlap. As the piston moves down, it uncovers the exhaust port first to let most of the exhaust out. Then it opens the intake port to let fuel/oil/air in. With a correctly-tuned expansion chamber in place, two things happen to help the intake process:

• As the exhaust gases expand into the expansion chamber, they create a vacuum at the exhaust port. This vacuum pulls fuel/oil/air into the cylinder.
• As the shock wave of the exhaust pulse hits the end of the expansion chamber, it echoes back, pushing any fuel/oil/air that got pulled through the exhaust port back into the cylinder. This page has a nice graphic that describes the process.

By pulling extra fuel/oil/air through the cylinder and then pushing it back in, the expansion port has the effect of stuffing more fuel/oil/air into the cylinder on each stroke. This gives the engine extra power in the same way that a turbocharger does.

Here are some interesting links:

• How Two-stroke Engines Work
• How Turbochargers Work
• Building your own racing Expansion Chambers
• Exhaust Pipe “Theory”
• Tuned Pipes

The new Yamaha RX-Z Malaysia Group has been setup in Google Groups for all us to share anything about Yamaha RX-Z 135 bike.

Posting in English and Malay are accepted.

Don’t just read, REGISTER NOW at http://groups.google.com.my/group/yamaha-rx-z-malaysia?hl=en

Yamaha RX-Z carburetor

Total votes: 117

The poll have shown that Malaysian prefers Yamaha RX-Z more than 125Z, but LC135 is now the second choice after RX-Z. The least bike preferred is FZ-150i, this may due to the design of the bike that is not compelling and futuristic enough like the rest.

Keep voting for the new poll! Look for it at the right sidebar.

The Doctor’s bike that gives us the mean 125ZR 46 Limited Edition:

Hit the links here:
http://www.yamaha-motor.co.jp/global/race/2006motogp_review/history/index.html