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Old 21st April 2009, 07:50   #1
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Lightbulb How come new 4 Stroke bikes can be started in gear ?

In the good ol' days of 4 Strokes like CD 100/4S Champions the bikes needed to be in Neutral to kick started. But the new bikes like Pulsar can be kick-started "in-gear" without the need for shifting it into Neutral.

So, what is the technical difference between the oldies & newbies ?
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Old 21st April 2009, 12:04   #2
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Quote:
Originally Posted by mithun View Post
In the good ol' days of 4 Strokes like CD 100/4S Champions the bikes needed to be in Neutral to kick started.
Been a long time, but I don't remember such a restriction when kickstarting my friends bikes just as I did my RX100 (in gear)?
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Old 21st April 2009, 12:09   #3
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GTO: Perhaps too long. Starting with bike in gear would result in bike lurching forward unless you also pressed the clutch. In the latter case mostly the kick would become free.

Interesting...would love to get an explanation.
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Old 21st April 2009, 12:10   #4
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Nothing to do with 4 stroke & 2 stroke. I am not sure of the technicalities but the then new 4 strokes didnt have the facility to kick start in any gear while the 2 strokes allowed it. Now-a-day all bikes can.

@Sudev- pressing clutch is obvious. The question is about being able to start the bike in gear by pressing clutch which the modern 4 strokers & 2 earlier strokers could

Last edited by Technocrat : 21st April 2009 at 13:37.
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Old 21st April 2009, 13:27   #5
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Default Primary & secondary

Here comes the technical explanation:

Since the "good ol" days, manual transmissions on motorcycles have used 2 types of starting mechanisms. The first (Secondary start) used a method where the main axle was turned by the kick gear (or the starter motor) via the transmission gear. Therefore it was necessary to kick without the clutch, necessitating that the transmission is set to the neutral position before starting. It was a simpler, cost-effective gearbox construction. The Hero Honda CD 100 and 4S Champion used this method.

The second method was the primary start, where the motorcycle is equipped with a mechanism in which the primary driven gear (a large speed-reducing gear) is turned by means of a kick idling gear and kick pinion. This enables the engine to start regardless of the position of the transmission gear once the clutch is released. Most modern bikes and all cars use this starting method.

Yamaha introduced the primary start mechanism in its first motorcycle, the 125YA1 (sometime in the 1950s). In India too, Yamaha was the first to introduce this tech on the RX100.
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Old 21st April 2009, 13:43   #6
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In India, KB-100's also allowed start-in-any-gear right from the beginning.
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Old 21st April 2009, 13:45   #7
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Yes Condor, infact it was only the CD 100 & 4S & some similar bikes which didnt allow else almost everyone did (not sure of Yezdi & the Suzuki AX100 though)
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Old 21st April 2009, 13:52   #8
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Quote:
Originally Posted by predatorwheelz View Post
The second method was the primary start, where the motorcycle is equipped with a mechanism in which the primary driven gear (a large speed-reducing gear) is turned by means of a kick idling gear and kick pinion. This enables the engine to start regardless of the position of the transmission gear once the clutch is released. Most modern bikes and all cars use this starting method.
In this case, what happens when we push start the car/bike?
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Old 21st April 2009, 14:08   #9
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Originally Posted by ms001 View Post
In this case, what happens when we push start the car/bike?
Push starting has nothing to do with the primary/secondary start mechanisms. In any vehicle, the transmission mechanism is connected to the engine. When you push start the vehicle, you are keeping the clutch pressed to disengage the transmission initially. The main axle rotates and creates momentum. When sufficient momentum is created, you release the clutch. Instantly, the main axle makes the transmission rotate, which in turn causes the engine to rotate and fire up.

In simple words, lets demonstrate the flow of energy this way:

Primary Start

Kick start/starter motor rotation > Primary Driven Gear > Engine (Transmision comes into play only after start)

Secondary Start

Kick start/starter motor rotation > Transmission gear > Engine (Protection mechanism to ensure no in-gear starts, as otherwise the main axle would also move forward)

Push Start

Main axle > Transmission Gear > Engine

Hope this makes your query clear.
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Old 21st April 2009, 14:53   #10
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^^
Thanks predatorwheelz, that is a very clear explanation.
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Old 21st April 2009, 15:27   #11
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my old KB100 (dec 95) could be started in gear by pressing the clutch. so could my brothers old 86 KB100. ditto my 2000 shaolin and dec 2k6 P180. the pulsar though won't even crank with the self starter while in gear unless the clutch is pressed and that i believe was implemented electronically - no big deal.
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Old 21st April 2009, 15:31   #12
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Quote:
Originally Posted by silver_shadow View Post
the pulsar though won't even crank with the self starter while in gear unless the clutch is pressed and that i believe was implemented electronically - no big deal.
No modern bike with a self starter will crank in gear, unless the clutch is pressed. Its an electronic cut-off designed to avoid damage to the gearbox and engine.
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Old 21st April 2009, 16:13   #13
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Something that was always in my mind! Good question!


Quote:
Originally Posted by GTO View Post
Been a long time, but I don't remember such a restriction when kickstarting my friends bikes just as I did my RX100 (in gear)?
Been a very long time, isn't it. The "good old" bikes that allowed were the 2-stroke ones, that is Yamaha, KB100, Suzuki.

Quote:
Originally Posted by condor View Post
In India, KB-100's also allowed start-in-any-gear right from the beginning.
Yup! One of the companions to Yamaha.

Quote:
Originally Posted by Technocrat View Post
Yes Condor, infact it was only the CD 100 & 4S & some similar bikes which didnt allow else almost everyone did (not sure of Yezdi & the Suzuki AX100 though)
Suzuki allowed this. And I believe Yezdi required you to come to neutral, since the gear rod was the kicker.


Quote:
Originally Posted by predatorwheelz View Post
Here comes the technical explanation:
...

Yamaha introduced the primary start mechanism in its first motorcycle, the 125YA1 (sometime in the 1950s). In India too, Yamaha was the first to introduce this tech on the RX100.
Thanks for the clear explanation, Predator.
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Old 21st April 2009, 19:27   #14
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my suzuki samurai starts in-gear if apply cluth. the reason i brought samurai because of that only in 2000. only rx-100 and kb had that technology.
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Old 22nd April 2009, 01:14   #15
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Quote:
Originally Posted by HappyWheels View Post
Suzuki allowed this. And I believe Yezdi required you to come to neutral, since the gear rod was the kicker.
Nope you can start the yezdi/jawa in any gear.
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