Choke and Starting

[Taman]

Not sure if I'm being thick, but I thought the choke did the same thing as the throttle - when you look where the wires go, it looks like when you use the choke, it just does the same thing as if you used the trottle.

Now then, when I start the bike, I generally use just the choke and reduce the choke a bit until the engine has warmed up and I can take the choke off completely. Then take off. I don't use the throttle at all.

I read on a forum that using the choke fouls plugs really quickly and that you should use the throttle to warm up the bike rather than the choke. Is this advice right, or dodgey??

[Scotty]

i thought the injected bike had the fast idol and the carbed bikes had the choke ?

[Taman]

Mines a 2001 and has a choke - maybe the later ones have a fast idle?

[Garry Hogan]

I'm sure that the injected bikes don't have the same kinda choke set up as the carbed Monsters. I believe that the 'choke' lever on the injected models is really just a fast idle lever and that the 'black box' that runs the injection system also senses when the engine is cold and makes the mixture richer when it is needed! But then again I could be talking out of my ear - but I think I is right :D

[Zimbo]

The purpose of the choke is to enable easier starting by causing the carburetors to produce a richer than normal mixture (that is, the proportion of petrol to air being introduced to the engine is higher). It does this by restricting the amount of air passing through the carbs, causing a greater suction within the carb which draws more fuel through the jets. Usually a cam operated by the choke mechanism operates the throttle mechainism at the same time, causing the bike to run with just a little throttle even with the hand throttle closed.
Generally you should use the choke to start from cold, and close the choke off once the engine has warmed enough to run without the choke being activated. As you use it only for a couple of minutes the plug fouling should be minimal. Use of the choke when the engine is running at normal temperature will cause a rich mixture, leading to increased fuel consumption and plug fouling over a period of time, as well as increased engine wear.

Fuel injected bikes don't have carbs, so the lever causes the fuel injection system to deliver slightly more fuel instead, as well as operating the throttle a little.

[CK & AK]

Zimbo is correct - on the ie bikes it isnt a choke, but a fast idle.
Saves you having to muck about with the throttle on start up.

On my M750ie I had it full open - before I turned the key to start bike.

On the current bike - M1000sie, I dont open it till AFTER the bike has fired on the key.

On neither bike do/did I have to touch the throttle when starting - indeed till I need to pull away.

C :)

[PaulS]

Garry Hogan is correct. The fast idle lever on injected bikes is simply that. It raises the idle speed by opening the throttle in the same way as turning the twist grip does and does not alter the fuel/air mixture in the way that a choke lever does on a carbed engine - the ECU does that. According to the owners manual the recommended cold start procedure (at < 35c ambient - very likely in the UK!) is to fully open the fast idle lever and start without using the twist grip. Once the engine is running adjust the lever to give a tickover of around 1500rpm until warm. I don't know why they have this lever as the ECU should be able to achieve the same effect - neither of the injected cars I've owned needed one.

[Taman]

Cool, so I'm starting it in a standard way and shouldn't be bad for my plugs. Seems to take 4-5 mins to warm up. Suppose that's not too long to wait!

Cheers