Dropping the idle from 1000rpm to 800rpm

[Bakdraft007]

I have just fitted electronic ignition.

One of the effects of this was for the engine idle to go up from about 800rpm to around 1000.

So I thought adjust it down. But exactly how do you do this? I looked in various manuals and in this forum. What is a very easy task on every bike and car I have ever owned seems to be a complicated affair on a stag. I am hoping that I have got it all wrong and someone is going to say just turn this screw and down she drops by 200rpm.

Any help appreciated

[ethel]

Assuming you've got the standard Strombergs, there's an idle screw on each carb that acts as a stop for a lever attached to the throttle spindle. The screws have a small spring around them and screw into a lug on the carb body, the one on the rh carb is easiest to see, just try operating the rods that connect the throttle cable to the carbs and you should be able to see where the lever comes to rest. The lh carb also has a stop/screw that acts on the choke so that the idle speed is increased when the choke is operated, this screw should be clear of the quadrant on the choke when the choke is closed so that it doesn't stop the throttle stop doing its intended job.
The correct way to set up the carbs is to disconnect them from each other and set them up individually, then replace the operating rods without disturbing the setting, but if your current set up is ok apart from the slightly high idle then I'd just try unscrewing both throttle stop screws by the same amount and see what happens.
If you look further down the posts on here you'll see I've been trying to resolve an issue with my idle speed.

John.

[Bakdraft007]

Assuming you've got the standard Strombergs, there's an idle screw on each carb that acts as a stop for a lever attached to the throttle spindle. The screws have a small spring around them and screw into a lug on the carb body, the one on the rh carb is easiest to see, just try operating the rods that connect the throttle cable to the carbs and you should be able to see where the lever comes to rest. The lh carb also has a stop/screw that acts on the choke so that the idle speed is increased when the choke is operated, this screw should be clear of the quadrant on the choke when the choke is closed so that it doesn't stop the throttle stop doing its intended job.
The correct way to set up the carbs is to disconnect them from each other and set them up individually, then replace the operating rods without disturbing the setting, but if your current set up is ok apart from the slightly high idle then I'd just try unscrewing both throttle stop screws by the same amount and see what happens.
If you look further down the posts on here you'll see I've been trying to resolve an issue with my idle speed.

John.

Thanks John, thats perfect.. a really good explanation... I will be adjusting later this morning... The reason I was not so sure is that the section of the ROM that describes this procedure was not very clear over the screws.. it mentioned them but did not picture them. Well it did not in the section for euopean stags, However, this morning I looked in the Emsiison control section and it is much better explained, and the pictures clearly show which screws are which.

Now if only I could find my old gunson carb balancer from my Dolly Sprint days... 35 years ago... hmmmm....

[wilf]

It could well be that the idle has changed due to the ignition timing being different? Not wishing to teach how to suck eggs, but have you checked that?

[marshman]

Just fitting electronic ignition on its own should not alter the idle speed, certainly not by 200 rpm, unless the timing has changed. Either the timing wasn't correct before, or it isn't correct now - or possibly both. Before altering the idle double check you have the ignition timing correct, also that the mechanical and vacuum advance are working correctly.

Roger

Whoops! Wilf beat me to it.

[Ceejay 72]

Just a possibility - could it be the tacho is wrong? When I bought my Mk 1 Stag, it showed idle at 1500 rpm. After I had the tacho converted for electronic ignition, the displayed idle dropped back to 800rpm, but the engine didn't sound any different!
Of course, if you have a Mk 2, this comment is irrelevant!

Chris

[Bakdraft007]

It could well be that the idle has changed due to the ignition timing being different? Not wishing to teach how to suck eggs, but have you checked that?

I checked the timing before ... it was on 14 degrees, then it moved to about 8 degrees after fitting the electronic ignition, so I moved it back to 14. I put it down to the fact that I had twin points that I had never checked... their gap could have been wrong or their relative placement, or their quality and that the new ignition was bettter. Also a better spark would also help.

Either way I have just backed it down ( Thanks John) to 650 rpm and she is ticking over nicely. Performance seems better in general too.

[Bakdraft007]

You know when you got it right when she ticks over like this

She was cold and when warmed up settled on 750rpm... beuatiful

Driven all day, not missed a beat.

[StagJonno]

Sounds good, and decent oil pressure for idling when warm. You're entitled to that nice, warm feeling