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Old 8th October 2006, 21:54   #1
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Default A very interesting question??

Read this question in today's TOI's mindsport.....

"You have an unbranded scooter. You are allowed to attempt starting it once. What would be the easiest method of telling whether it is a two stroke or four stroke engine? You have to answer BEFORE the scooter starts.
Submitted by Saurabha, IIM Lucknow "

I feel this question to be slight incomplete. It is not mentioned whether the scooter is supposed to be kickstarted or electrically started coz I feel the answer lies in the sound of the starter.

By the way, I guess that the phrase "BEFORE the scooter starts" means before the engine starts firing.

Keep those answers coming..................
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Old 8th October 2006, 22:02   #2
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No fuel pump present in 2 strokes where as a fuel pump is present in the four strokes.Just bend down and observe
Also looking at the head u can make out wheather its a two stroke or 4 stroke.
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Old 8th October 2006, 22:10   #3
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Perhaps the author meant that we can CRANK the engine once, but we cannot actually fire the engine, or allow it to start.

Kick or electric, there's only one way to tell; the exhaust note/starting note. While cranking, the depth of the notes can probably be identified by experienced ears. Unlike motorcycles, the weight of the kick lever cannot be used to ascertain the nature of the engine of a scooter.

There's another slightly effective way- wind the throttle to halfway and crank/kick. If it makes a "hollow" sound, it's a 2 stroke. Very subtle, though.

The final way is- if the engine is visible, the placement of the spark plug and general view can tell if it's a four stroke or a two stroke...without even touching it..

And finally, if none of these click...toss a coin to find out....

@humyum: A fuel pump in a carb four stroke scooter?? Which one has this contraption? Or do you mean the force-feed choke? Even some MPFI scooters do not have a pump because fuel delivery is gravity-assisted.

Last edited by veyron1 : 8th October 2006 at 22:13.
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Old 8th October 2006, 22:48   #4
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Yeah four stroke scooters do have fuel pumps.My dio had one and so do mostly all the four stroke scooters and by scooters i mean moped as the topic says scooters(not bikes).
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Old 8th October 2006, 22:59   #5
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would the scooter be new? or old? ie, used or not?

oily exhaust: 2 stroke?
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Old 8th October 2006, 23:12   #6
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i think the easiest way would be to check the manual. thats not disallowed now, is it ?
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Old 9th October 2006, 01:07   #7
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Hm. Four-stroke FI bikes (SBKs, and more recently, Glamour FI) DO have pumps, but I wasn't aware of carb'd scooters...seems like the local Honda workshop's gonna have a visitor soon.

Now- we can identify the scooter engine's cycle (2/4 stroke) by looking at the engine. Or looking at the manual. Or by physical verification.

What if we can't see the engine, and are allowed to CRANK it just once before identification?
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Old 9th October 2006, 08:10   #8
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Quote:
Originally Posted by salilpawar1
Read this question in today's TOI's mindsport.....

"You have an unbranded scooter. You are allowed to attempt starting it once. What would be the easiest method of telling whether it is a two stroke or four stroke engine? You have to answer BEFORE the scooter starts.
Submitted by Saurabha, IIM Lucknow "

I feel this question to be slight incomplete. It is not mentioned whether the scooter is supposed to be kickstarted or electrically started coz I feel the answer lies in the sound of the starter.

By the way, I guess that the phrase "BEFORE the scooter starts" means before the engine starts firing.

Keep those answers coming..................
no, as per the question nobody is allowed to read the manual....
Since the question is from Mindsport, it will definitely have a sensible answer and it should be answer only while cranking the engine although there is liberty to give other simpler solutions.......
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Old 9th October 2006, 09:23   #9
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How about trying to kick the scooter to life with the clutch pressed?

I'd say this isn't possible on the four stroke scoots.
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Old 9th October 2006, 11:17   #10
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Yes, airfoil, I was thinking the same too. Been off 2 wheelers for a while now, but this was how it used to be for the old hero hondas. Wouldn't start in anything but neutral ('cause you couldn't start with clutch depressed). But the 2 strokers would start in any gear, with the clutch depressed.
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Old 9th October 2006, 11:19   #11
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Since, 2T oil needs to be added only for 2 stroker, I would lift the seat to see if there is a 2T oil tank or check to see if there is some indication that suggests that 2T oil needs to be added directly to the fuel tank?

This can sometime also be found out by the tightness of the accelerator. If it is tight, it means the throttle cable has two components in it, one for the carbeurrator and the other for the oil-pump.
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Old 10th October 2006, 04:57   #12
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really simple man..just take a look at the exhaust. The 4-stroke exhaust and 2-stroke set-ups are really easy to make out. Also a half kick will reveal the story.
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Old 10th October 2006, 05:01   #13
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Quote:
Originally Posted by S@~+#0$#
This can sometime also be found out by the tightness of the accelerator. If it is tight, it means the throttle cable has two components in it, one for the carbeurrator and the other for the oil-pump.
not really...some makers use the throttle cable split to use an ignition advance switch..like on the scooty pep. so its hard to comment that way.
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Old 11th October 2006, 08:42   #14
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Quote:
Originally Posted by fieroid
not really...some makers use the throttle cable split to use an ignition advance switch..like on the scooty pep. so its hard to comment that way.
You are right fieroid, I did not think of that.

Quote:
Originally Posted by fieroid
Also a half kick will reveal the story.
Also, I have a feeling that this might be the right answer. Let us wait and see.

salilpawar1 Bro, do you have the answer yet? We are all waiting.
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Old 25th November 2006, 19:30   #15
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Default basic difference

two strokes doesnt have valves, instead they have ports, where as four strokes has valves, may be you can check out the cylinder(if it is easily visible) and then make it out whether its a 2s or 4s.
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