Throttle cable adjustment

[Revvers]

Hello. Have looked at both Haynes and Sticky's manual and still need a proper explanation of how to set up! I have a Dellorto phbh carb. Question: where is the starting point for adjustment? Cable all connected. How do I know if I have the correct tension in the cable before using the adjusters on the carb? Thought I had it set up ok but out on the road as soon as I let the throttle back, the bike died. Is that right? Have not touched the idle or mixture screw. I have no rev counter and I just need an idiots guide to setting it up properly. Should the bike die with no cable adjustment or do I have another problem? (Came back from a shop like this but I've had enough of them) thanks

[CHRIS in MARGATE]

Aha.... That shop !

Firstly you need to take all of the slack out of the cable because if not the outer cable has a habit of jumping out of its stop when you throttle back. I think from your set up you will need to make sure you have pulled it just tight enough at the headset end and tightened the solderless nipple so that is tensioned with no free play BUT not lifting the throttle side at this point. At the carb end make sure the adjuster on the end of the cable is screwed in all the way and then just about half to 1 turn out to allow you to adjust either way if necessary. After a couple of weeks you can take up any stretch here.
Now screw the tickover adjuster in a little and you will see the slide lift. Familiarise yourself with this adjustment. Always wind the throttle open and let it return as well. Now you know where this screw is adjust it so the slide just lifts a little and you can barely see under it.
Start the scooter with choke...No thottle should be needed. Warm it up ...might take 5 to 10 mins. Now raise the tickover a littke more with the previously mentioned screw so it is just a little too fast.
Adust the mixture screw 1/4 a turn at a time until you get the highest tickover speed. Keep revving between adjustments ! When you are satisfied with that then lower the tickover with the first screw you used to lift the slide. Rev it up and see if it it comes back cleanly to tickover. If it appears to take too long to settle back then the airscrew is set too weak and will need readjusting 1/4 turn at a time. If it is boggy (snuffly) then the airscrew is too rich.
When correctly set you should be able to cofidently stop at a junction and take your hand off the throttle.
Last bit of advice.....check plug colour. Mid brown is perfect. Any lighter ...dangerous to the engine.
Best of luck. Chris

[Revvers]

Cheers Chris. That's a bit more detailed than the other avenues I've explored!! Much obliged. Hoping to be able to enjoy the old girl again after this!