125 Choke Problem...

[Ted]

I've got a Gilera Coguar 125cc, I believe it has the same engine (or very similar) as the Honda CG.

The choke lever has 3 positions; up, down and middle... just to make sure... up is choke on, down is choke off, and middle is semi, is that right, or is it the other way round?

I've been starting the bike with the lever in the up position, then letting it sit and warm up while I get ready to go (2-3 mins), then if I move the lever to the down position, the bike stalls, but it's fine if I move the lever to the middle position. However... the bike starts juddering about 1/4 mile down the road... as if its running out of fuel, yet the tank is full and the tap is switched on. If I try moving the choke lever to the down position the bike stalls, again, but if I put it back to the up position the bike runs fine. So I thought I must need to warm it up for longer before taking it out of choke, so I rode it about 3 miles, then tried moving the lever to the middle position, once again, the bike idled fine, but started juddering about 1/4 mile up the road, again!

What am I missing?
How much do I have to warm up the engine, and how?

[veeeffarr]

I don't ever use the choke, never really had to.

Hold the throttle open a tiny crack while kicking the engine over (Or using the E. Start if you've got one).

There's a knack to starting these engines, you'll get it!

[Ted]

Unfortunately I've only got an electric start... which to me makes it seem less of a bike, and more of a moped!

Anyway, I've got no trouble starting the bike... that is easy, and it will idle no problem, but I can’t ride it unless it’s in choke...

[veeeffarr]

Leave it for about a minute after start it, then slowly twist the throttle on... If the engine bogs down, let it return and twist it again...

Keep doing that until the revs are increasing solidly.

[Ted]

Is that with the choke on, off or in semi?

I've been leaving it with the choke on for about 2 mins, then switching it to semi, and driving off. It’s fine until about a 1/4 mile down the road...

[Ted]

Should I just 'bomb it' down the road for a couple of miles in choke, and see if I can then switch the choke off this time?

[veeeffarr]

No,

Don't ride with the choke on.

Use the technique I described with NO choke, keep opening the throttle slowly until the revs increase and the engine doesn't bog down.

If it does bog down, shut the throttle off again.

[finpos]

Agree with Toby - every air-cooled small bike seems to need a knack to starting it, but it should be up to temperature (i.e. no choke required to idle) by the time you have your helmet and gloves on.

If you've been riding a few miles with the choke on, a new plug may help put things back to normal - you've probabaly borked the one that's in it!

finpos.

[veeeffarr]

Try and avoid using the choke as much as possible