Choke

[Gazdaman]

On my mz 125 ETZ, it has a chock that you have to hold in the start position. Wierd thing is, the bike starts better without it.

My understanding of the choke was that it just increased the revs, if I put the choke on with the engine running, the engine dies very quickly.

Is my idea of how a choke works horribly wrong?

Gaz

[JodieWodie]

If your engine is running okay, then you don't need a choke....

my understanding is.....if your bike is cold...damp...won't start...dies...then you need the choke on....

If it has already started ..you don't need it at all...

(oh..and the choke increases the mixture...not the revs...it is more fuel enriched)
____________________
Courage doesn't always roar. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow"

[MarJay]

Nope.

A choke alters the mixture, not the revs.

Basically what the choke does is allows less air into the engine for the same amount of fuel that would normally go in. This makes the mixture easier to ignite as a greater percentage of it is fuel. However it makes the engine inefficient and make loads of emissions.

If you don't need it, don't use it!

Its usually only /really/ needed on cold days on a well set up engine.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[mr jamez]

The choke literaly chokes the air supply, which in turns richens the mixture, which will help it start on cold days and lower the time it takes to warm up. Don't ever leave it on for very long though, you shouldn't have to use it in warm weather

[Gazdaman]

ah, makes sense.

Just I'm fairly new to my bike at the moment, and I'm still getting the feel of how to start it, i.e what it likes what it doesn't like.

sometimes I'll have to bump start it, sometimes it'll start second kick (never first).

and twice it's taken several bump starts to get it going.

Gaz

[Jammy-G]

If more petrol is going in it washes away the oil so you'll be left with a very poorly barrel and piston if you forget to turn it off ! It will conk out if you leave it on for a long time though, the plug will foul.

I ruined my bore when I had a choke problem and didn't know about it. Went through about 4 plugs a week, finally found out my bike was running with the choke out! Had the piston out and the scoring was immense !
____________________
RooRoo: just like the time i stuck my finger up my arse with no lube at all and she didnt talk to me for hours

[Kickstart]

Hi

The choke on most 2 stroke just allows more petrol in to richen the mixture. Some of them have a ticker instead just to dump some more fuel in before you try starting it.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stryker]

Just to confuse things, some chokes kinda have a little cam so they not only restrict the air but do also add a little throttle to raise the idle RPMs although the richer mixture does raise idle anyway.

If your bike runs better without it, then maybe its running a little rich already? Thats a guess on my part, bike engines are rather new to me

[stinkwheel]

It is an MZ and so likley has a Jikov slide carb. These are quite clever in that they have a seperate choke jet. When you switch the choke 'on' a passageway changes so instead of using the idle jet for fueling at tickover, it uses the bigger choke jet.

MZ 2-strokes were originally designed for use in East Germany...it gets Fecking cold there in winter (like rivers freeze solid) so their idea of what constitutes cold starting and what we do are two entirely different things.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.