Four stroke technology in smaller engine capacity motorcycles continues to improve by leaps and bounds. This improvement is thanks in part to participation by the Japanese manufacturers like Honda, Suzuki and Yamaha in the annual MotoGP Championship series where 1,000cc prototypes are entered for competition.

What has MotoGP got to do with the R&D on the performance of such kapchai bikes?

Plenty. Chief among the improvements is the ability to make 4-stroke technology to be as agile and faster than the discarded 2-stroke version over the years after 4-stroke MotoGP prototype bikes were introduced in 2002 to take over the mantle from those 2-stroke-based, 500cc machines in the Championship.

Of course, those MotoGP prototype bikes are 1,000cc beasts, which are doubled the capacity of the 2-stroke 500cc. But that’s needed in order for a 4-stroke version to outperform a 2-stroke bike. However, conventional 4-stroke kapchais are mostly in the 100cc to 125cc range, almost the same for their 2-stroke counterparts.

So how does this translate into better and faster performance over their 2-stroke cousins?

The answer is both Yes and No.

Yes, in the sense the modern 4-stroke version is much faster and agile than those 2-stroke bikes produced during the 90s, and throughout first decade of the 21st Century as not much new development has gone into the latter as the world has more or less embraced the cleaner engine combustion, thanks in part to the compulsory emission control via Euro4 now enforced in Europe, as well as the United States where all kinds of 2-stroke bikes are simply non-legal on public roads.

No, in terms of – if R&D on 2-stroke technology is still ongoing strongly between the Japanese manufacturers, then the modern 4-stroke bikes would have a harder time in beating those speedy and lighter 2-strokers.

For the nearest comparison, it is safe to say all the latest 4-stroke kapchai would be able to outperform any outdated 2-stroke bikes that are still roadworthy in the present day.

Case-in-point would be my ageing Honda NSR150RR – a 2-stroke sportsbike against the latest Honda Cub/kapchai in the market – the Honda RS150R, a 150cc 4-stroke with a 6-speed transmission and bigger tyre profiles for front/rear than a conventional Cub. Oh, that 6-speed transmission is not automatic as a manual clutch lever is needed to operate the RS150R.

Where standard acceleration is concerned, the Honda RS150R is as fast as my NSR150RR. In fact, I came across a rider on the RS150R prior to doing this review, challenging me while I was on the NSR150RR. Of course, tried as much as he could, there was no way he could overtake my NSR150RR on the highway leading to Purtrajaya from Bandar Salak Tinggi located in southeastern area of Selangor. Nevertheless, that RS150R rider was very close behind. The higher top speed of my NSR150RR also prevented him from overtaking me as the RS150R’s top speed maxes out at 145km/hr (on speedometer) while my bike could hit 165km/hr (measured). Yes, it was the NSR’s top speed that prevented the RS150R from being ahead.

Had I came across that rider while negotiating S-curves on twisty old roads, there’s no doubt the RS150R would have outperformed the NSR150RR easily as old 2-strokers are somewhat slower in getting up to speed in such a condition as opposed to riding on wide-open highways.

Honda normally designated its 4-stroke street bikes with the R-code to denotes its racing heritage, such in the case used for its 1988 VFR750R aka the RC30, the RVF750R aka RC45, both of which are WorldSBK-championship winners during their era. The latest R-series street bike with racing heritage is the RC213V-S, a limited edition 1,000cc racer-replica of HRC’s Championship-winning RC213V MotoGP prototype which took Spaniard rider Marc Marquez to the titles in 2013, 2014 and 2016.

So with the 150cc kapchai being given an R-designation in the form of the Honda RS150R, you can rest assured of its intended racing heritage when the standard parts are replaced with race kits. Yes, the RS150R is designed to win the annual Cub Prix Championship in the 150cc category so where performance is concerned, it is definitely not a slouch.

What exactly the RS acronym stands for, I have absolutely no idea but my hunch is it could be for “Racing Standard 150 Racer” or “Racing Series 150 Racer”.

Also, HRC used to have the RS-designation on its line-up of production racer bikes of 125cc, 250cc and 500cc during the 90s era of the 2-stroke championship, each designated as RS125, RS250 and RS500 respectively.

The list of features is extensive, to say the least. Starting with the LCD panel aka as the Advanced Digital RPM meter displays info such as RPM, speed, gear engaged, fuel gauge, odometer and tripmeter in a clear and precise manner that is clearly visible for the rider. Its headlight is LED-based, which gives a brighter illumination at night as compared to tungsten bulbs used by many kapchais in the market. Even the taillight is LED and designed to be stylish while still providing a bright backlight that gives better visibility to other motorists during daytime and night.

Engine-wise, the RS150R is equipped with a 6-speed DOHC 150cc single cylinder engine equipped with a liquid cooled system. The exhaust pipe is made from the same material that is used for the company’s recently-introduced CBR250RR sportsbike built in Indonesia but is yet to be marketed elsewhere other than domestic Japan.

I managed to achieve a top speed above 140km/hr based on the LCD panel readout with the RS150R. And unlike its siblings of kapchai in Honda’s line-up, the RS150R comes with tubeless, high performance tyres, with the rear featuring a 120/70 of 17-inch size, which is the same specification as the front type used in most bikes with engine capacity of 600cc and above.

Despite loaded with mouth-watering features, the RS150R has one limitation. Given the actual engine capacity of 149.16cc, the bike only has a fuel tank load of 4.5-litre, which is less than the MSX 125cc that holds up to 5.7-litre, and enough to last a mileage of more than 200km as opposed to the RS150R, which gets you to nearly 180km mileage per full tank, given its higher capacity and power.

The 20km+ difference will be felt more when you realize the nearest petrol station is 15km away but your bike only has enough to last another 10km or less. This doesn’t make the RS50R a petrol-guzzling beast, it is just the tank capacity is a little on the smaller size given it’s a vast list of features and performance to complement them. To be fair, as long as you are riding the RS150R within the city or from a small town to the next, it shouldn’t be an issue. However, if you are planning a long haul trip, you will face more stops for refueling at those towns along the routes particularly when riding at speeds above 120km/hr.

Overall impression of the RS150R is – it’s the best motorcycle available right now especially if you are looking for a compact, lightweight and easy-to-ride model below 200cc, with power and acceleration factors that are more agile and better than the dozens of kapchais out there.

Posted by Philip Chong

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