The technology behind clutchless motorbikes

If you were looking to buy a motorbike or a scooter in early 2000s, you had an unique offering in the market. They were the then Hero Honda Street 100 and TVS Jive, India’s only geared motorbikes without clutch levers. They were breakthrough products but aren’t on sale anymore.

Why were they unique?

These clutch-less motorbikes were different because they reportedly had three technologies incorporated for transforming a normal geared motorcycle with a clutch lever into a semi-automatic model. The technologies includes rotary gear system, centrifugal clutch and integration of clutch cable with gear lever. The three tech work in tandem to help a rider to completely avoid using a clutch lever which has turned out to be the prime cause of tension and unintentional halts while riding a usual manual transmission motorcycle.

Rotary gear system

The rotary gear system in motorcycles without clutch levers help in seamless slotting. For example, in a normal geared motorcycle, we can go from neutral to the top gear but have to return back to neutral. But, in a rotary gear system, we can literally circle around with the gears. That is we can go from neutral to the top gear and vice versa any number of times in the same direction. In a normal motorcycle, if we are stuck in traffic in fourth gear and want to come to first, we have to engage gears backwards one by one. But, in a rotary gear system, we can just press the lever two times in the front and go from fourth to first via the neutral.

Centrifugal clutch

The centrifugal clutches in these motorcycles prevent them from stalling in heavy traffic. In a normal motorcycle, if the engine rpm and wheel rpm with all gear ratios in place don’t match, then the engine knocks and stalls if we don’t press the clutch lever on time. But, if a centrifugal clutch is in place, it automatically disengages in the engine from the gearbox if the engine rpm goes below a threshold limit, say 1,000 rpm. So, a motorcycle with a centrifugal clutch never halts in traffic.

Integration of clutch cable

In a normal geared motorcycle, the gear and clutch lever are separate and need to be operated individually. But, in motorcycles without clutch levers, the clutch cable is attached with the gear lever itself. So, while changing gears, all we need to do is go ahead and slot them. When we press the gear lever, the clutch automatically actuates, disengages the engine for seamless shifting. When we remove our foot from the lever, the clutch again engages the engine and gearbox.

So, in the end, with these three technologies, we can ride a geared motorcycle like an automatic scooter but without losing the essence of a motorcycle; its high performance and fuel efficiency. Street was launched in 2000s when petrol was cheap. Also when TVS launched the Jive in the 2010s, it was a sales success for many months but later the brand failed to update the product to keep it fresh. Nevertheless, even today there are thousands of Streets and Jives on our roads.

S Ben Raja