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Choke..

Discussion in 'New Riders and Riding Tips' at netrider.net.au started by mr_messy, Dec 24, 2006.

  1. I was just wondering, during my long trip from Sydney, can you use the choke as a form of cruise control?
    I mean, when you pull the choke out enough it will rev to a certain rpm.



    I can't explain the reason why I didn't, I was thinking it might be too lean or something and melt the engine. I don't know how I came to that conclusion.
    My mechanical knowledge is very basic.
     
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  2. No.
    The purpose of the choke is to enrich the fuel-air mixture to enable a cold engine to start nd run. Some do it by restricting the air supply (hence the name) and some by providing extra fuel. Operating the choke usually also advances the throttle a bit.

    Using the choke when the engineis hot could have a number of effects, depending on the way a particular motor works.

    On my bike, it would make the engine stall. If you could keep the motor running it might just make it run rough. There wouldbe loss of power and increased fuel consumption. I don't *think* it would cause overheating, but you might get a nasty carbon build up in the cylinders.
    Generally not a good idea.

    A sore wrist can be a sign that it's time for a break (said the actress to the bishop).
     
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  3. I think I am right in that in petrol engines, more fuel means cooler running temp.
     
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  4. Fouled spark plugs as well :!:

    You can buy a few different cruise control accessories
     
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  5. Have you tried one of those throttle rockers? Cheap, quick and easy. :grin:
     
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  6. +1 - go the throttle rocker and have regular rest stops. Don't use the choke, it's not there for the use you mention.
     
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  7. I'm not fond of the throttle rocker. I have one, and used it on some of the long stretches across the Nullabor, but I don't like the way it gets in way in ordinary riding. On a closed throttle, it makes it harder to operate the front brake. It could be dangerous.

    Unless you have very heavy throttle return springs, your wrist should not be strained in normal use. Many people grip the throttle too tightly, and this can cause pain on longer rides. I find that shifting my hand position from time to time helps, as does maintaining a light grip. Actually, maintaining a light touch on the 'bars can improve your riding as well as reducing discomfort.
     
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  8. I've found under relatively constant throttle settings, like freeway cruising, that if I put a lot of my hand on teh bar end, and use my thumb and index finger to modulate throttle, it's lots better.
    What happens is you now have something fixed to move your throttle against, so you can rest a whole lot of muscles in your forearms/hands.
    I've also found it allows much finer throttle movements.

    Regards, Andrew.
     
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  9. Previous posts are right, cruising with the choke on will result in increased fuel consumption, reduced power and fouled spark plugs. Definitely don't recommend doing it.
     
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  10. Slightly off topic, I find my choke doesn't do much. When I start the bike I try putting it on a bit, but doesn't really do anything, and as I slowly increase it still doesn't do anything until finally it stalls when I put it on all the way. Any ideas?
     
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  11. Easy

    Kill the bike :rofl: :rofl: :rofl:
     
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  12. Lol jeff, per your advice I gave it a good kick. But avast, to no avail! (yarr!)

    :cool:

    I read something about adjusting the need to adjust the choke or something, but it didn't explain how..
     
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  13. Nah....................ya just got to go it with a big stick until it learns its lesson or dies.
    At least thats what I did with my kids :rofl: :rofl:
     
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  14. To use the choke you put it all the way on, then gradually decrease it as the bike warms up. So, turn the ignition to on, pull the choke all the way to 'on' (generally this means pulling the lever down all the way), press the starter button then once the bike is idling you reduce the choke gradually until you hear the revs stabilise for the position the choke is in then you back it off a little more and repeat until it's fully closed.

    How long you need to use the choke for depends on the temperature of the engine, you will find that you will decrease it at a slower rate in winter than in summer. Of course if you have been riding the bike for a while then nip into the shops you probably wont need to use the choke again to start it up.
     
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  15. Thanks Haggismaen I'll have a punt when the world stops shaking :(
     
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  16. It's possible your bike is already running rich at low RPM, and that's why it doesn't need or doesn't like the choke. Maybe a tune-up could be in order?
     
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  17. Using your choke to increase revs above an idle so you can lazily coast will not hurt your engine. Using your choke will increase fuel consumption while riding in this fashion compared to using the throttle to travel at the same speed. I use my choke whilst in top gear to coast at 80 kmh going down the tunnel. This is what happens when the choke is applied.

    An internal combustion engine creates a lower pressure as the piston travels downward when it begins its fuelling/compression cycle. Because of atmospheric pressure outside the engine is now greater than in the cylinder at that point air is forced into the combustion chamber via the carby.
    When you activate the choke on your carbied bike, a butterfly in the throat of the carby rotates minimising this airflow which is caused from the lower pressure in the engine during the fuelling cycle via the carburettor acting as an obstruction slightly starving the engine of air. The engine is still trying to inhale the same volume of air but because of this obstruction caused by the butterfly minimising air flow it now tries to obtain that same volume through fuel filled jets/galleries inhaling fuel at an increased fuel to air ratio. This is what causes the engine to not run smoothly when the choke is applied. This will not harm the engine because fuel is part of the lubrication/cooling process in an engine. Though minimising fuel to air ratio can harm the engine but this doesnt occur using the choke.

    I probably got carried away here a bit but now you know whats happening when using a choke.
     
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