Why do ppl open throttle b4 turning e engine off?

[Blahhh]

I was at JB the whole day at a workshop. Saw alot of bikes come and go. I noticed dat some have a habit of opening the throttle, before shutting the engine off when they are parking their bike. I asked one of them and he told me because that helps to clear excess carbon. How true is that?

[pyro13]

so that to start the engine its easier.. ter is oil flowing in the carb...

[bluelabel]

i think it will hurt ur pistons more , by doing that ........ ram ur engine den straight away off ur bike , ur piston will suddenly stop (so i guess its bad for ur piston)

 

and alot of ppl i ask why they do that , will always tell me de same ans , clear excess carbon ..... but for wat i think is , when u throttle , petrol will enter den u straight away off ur engine , ur petrol dont get to burn , and it sits in somewhere in ur carb and acts as a lub , so de carbs dont rust

and usually ur carb gets flooded when u do dis .... and makes it harded to start ur engine de next time round.

 

 

cheers

.... i dont really know whether its true wat i said or not ...

but its just my 1 cent worth

[pyro13]

well, it makes sense..

[Raptor]

It is an ego thing. Its a show off thing.

Rev the bike to announce your arrival.

Does not have any effect on the carb nor does it clear carbon.

 

A lot of times people do things that are activity driven without any purpose. They do it because others do it... that's all.

 

When you understand the principles of carburettion and how carbon is built up in an exhaust system.. you will realise that revving the engine first then instantly cutting off actually has a very negative effect on the engine.

 

Or not I think you will see the Motogp bikes do the same thing. They don't. They pull in the pits or winner circles and shut off the engine whilst the engine is at idle.

 

Anyway I personally feel that this having to rev the engine before shutting down is a very Ah Bengkish behaviour that has been passed down from generation to generation. Just my 2 cents.

 

Sorry if I have offended any Ah Bengs here.

[redbeacon]

I do that to (get some biting point) to shift my gear to neutral in preparation for parking

 

Hehee...

[stsoh]

i thought read it somewhere in sbf......found it in Engine etiquette last paragraph.

 

extract it 4 all to read;

======================

One last thing

Everyone does it, and no-one knows why: that last blip of the throttle before you turn the engine off. If you have a Scott Squirrel two-stroke it might help clear the plugs, but for the rest of us it has the unhappy consequence of dumping a large shot neat fuel down the bores, washing the oil away. That means extra wear when your start up or corrosion if you leave it standing for too long. So don't do it.

======================

[dinie]

stsoh is so right... if u throttle right before u turn off ur engine, the petrol washes the lube away from ur piston.. so there'll be much more damage when u do a cold start the next time...

[Guest NPNT]

and also to waste petrol?

[dinie]

Originally posted by newbie@Dec 24 2006, 01:10 AM

and also to waste petrol?

haha not really lar.. u dun really use much petrol at idle.. cos there's no load.. don't believe? try switching the fuel c*** to 'off' and blip ur throttle once or leave it to idle.. on my TA150 it takes at least 4mins for the engine to die off..

[dinie]

crap apparently the word C-O-C-K is a vulgarity and becomes automatically censored in ur posts.. but tts wad its called right? a fuel C-O-C-K? its definitely not a fuel gauge cos a gauge is used to measure sth..

[natgw]

ppl do that to flood their carbs so that they will have problems starting their bike after that.

[Guest NPNT]

Originally posted by dinie@Dec 24 2006, 04:02 AM

haha not really lar.. u dun really use much petrol at idle.. cos there's no load.. don't believe? try switching the fuel c*** to 'off' and blip ur throttle once or leave it to idle.. on my TA150 it takes at least 4mins for the engine to die off..

i understand what u mean. by idling and throttling different mah. idling can be from 800-1200rpm... but once u pull, can go up to 3000rpm mah.. so fuel being consumed during the throttling part is higher than idling.

 

so leaving it idling for 4mins is possible, but not when pulling throttle for 4mins at neutral.

 

dats what i mean by waste petrol.. hope u understand my point.

[Guest NPNT]

Originally posted by no.license@Dec 24 2006, 05:42 AM

ppl do that to flood their carbs so that they will have problems starting their bike after that.

haha so they love problems hah?

[compfused]

Sometimes they do that coz very difficult to go in neutral..I personally don't do that unless very difficult to go in neutral..

[Raptor]

Originally posted by compfused@Dec 24 2006, 09:52 AM

Sometimes they do that coz very difficult to go in neutral..I personally don't do that unless very difficult to go in neutral..

There is no link between engine rpm and the clutch and finding the neutral gear.

 

The clutch only transmits the engine drive to the rear wheel through the force of the clutch springs acting on the clutch plates. When you pull in the clutch.. you work against the clutch springs and forcing the clutch plates to be disengaged from the engine drive. When you kick the gear shifter, you are only moving the gear train from one gear to another... sometimes this gear train gets caught in a mid-zone and does not want to drop into neutral or first gear.

 

That is why when you turn on the ignition but dont start the bike.. it is sometimes very difficult to put the bike into first gear... then you start rocking the bike while stepping down on the gear and it drops in.

 

You are better off slipping the clutch slightly and kicking the gear into neutral when the bike is moving forward slightly, a motion equivalent to rocking the bike forward and backwards.

[compfused]

Originally posted by Raptor@Dec 24 2006, 10:29 AM

There is no link between engine rpm and the clutch and finding the neutral gear.

 

The clutch only transmits the engine drive to the rear wheel through the force of the clutch springs acting on the clutch plates. When you pull in the clutch.. you work against the clutch springs and forcing the clutch plates to be disengaged from the engine drive. When you kick the gear shifter, you are only moving the gear train from one gear to another... sometimes this gear train gets caught in a mid-zone and does not want to drop into neutral or first gear.

 

That is why when you turn on the ignition but dont start the bike.. it is sometimes very difficult to put the bike into first gear... then you start rocking the bike while stepping down on the gear and it drops in.

 

You are better off slipping the clutch slightly and kicking the gear into neutral when the bike is moving forward slightly, a motion equivalent to rocking the bike forward and backwards.

Thanks for the enlightenment..

[wait4me]

i tot normally onli class 2 bikes do it

 

didint know 2b bikes also doing it now

[wait4me]

i tot normally onli class 2 bikes do it

 

didint know 2b bikes also doing it now

[rhema83]

Originally posted by wait4me@Dec 24 2006, 06:56 PM

i tot normally onli class 2 bikes do it

 

didint know 2b bikes also doing it now

If you look at experienced riders who are knowledgable about engines, even if they blip the throttle to "annouce their arrival" (which I am sometimes guilty of), they will let the engine fall back to idle for half a second before turning off the ignition. A modern sportsbike's response is fast enough that the engine would be back in idle by the time the rider takes his hand off the throttle and grabs the key.

[voodoodoll]

Originally posted by redbeacon@Dec 23 2006, 11:35 PM

I do that to (get some biting point) to shift my gear to neutral in preparation for parking

 

Hehee...

u can just off the engine and kick to neutral.

[200sx]

other then those, do we off the red RUN button and turn the fuel switch to off so that we can start it easier the next day?

[william_liu]

The red kill switch won't help your bike to start easier the next day... and unless your carb is faulty, there is no real need to switch your fuel switch to 'OFF'.

[yanuk]

switching the fuelcocK to off is another myth passed down. The theory goes that the fuel will keep dripping into the carb and flood the carb making starting the next morning very hard. The theory (from what I was taught) was that when the carb overflow, it will flow into your chambers and if you left it long enough, your chambers will flood as well and you can prepare for a overhual. *LOL*

 

I've never took up that practice and my friend was a bit pissed with me for that saying "I don't look after my bike"

 

Even during my BMT days where I left my 2B bike at home the entire week, and ride it only on weekends, No problem starting it the first time.. LRI sure pass ah!

[moccajava]

very true. monkey see monkey do. it IS bad practice.