Dellorto PHBH Carburettor

[GLscoot]

Im going for the AS264 first and will ask about the needle at the same time. Im pretty happy with the speed already I got it up to 62mph and it still had more, in fact I had to back down because the front wheel was rarely touching the ground and i would say the front end is to light. I was looking for the acceleration through out all the gears, which I have. I even think I could push it to 60mph in 3rd, if I had the hazels. Thats if the SIP digital speedo is telling me the truth.
Cheers Gary

[coaster]

I still think you are possibly over complicating things. Your original post says the problem occurs when it's been idling for a while. It also says if starts from cold without the choke. Both of those statements point to the idle circuit being too rich. As the scooter is performing ok in the rest of the rev range, I would advise you to concentrate on the idle jet and air screw, try a smaller idle jet and see if you can set the tickover with the air screw. As I mentioned above, the atomiser doesn't 't come into play until around 1/4 throttle so it won't affect the Rickover, neither will the needle or main jet.

[GLscoot]

Coaster
i re-read all the posts and I am putting together a list of jets, atomisers, needles ect just to be on the safe side and that I have things I can change individually and one at a time so I can work out what the problem is. I have this carburettor set uo on a couple of my scooters, so the parts will be used as spares and back up. Its going to be a slow process working it all out. Cheers for the information and help.
Gary

[paulnobodyimportant]

Agree with Coaster, it's all tied up with your idle circuit. I would try to get that right, before you dabble with needles and atomizers, but good luck.

If you haven't seen this info from CamLam, worth having a read first

http://www.lambretta.co.uk/downloads/carbsetup.html

[tonydevon]

check out wasp performance for atomisers etc etc theres Av and AS to choose from

[GLscoot]

I found this on google which was very usefull especially the pdf manual.
http://www.bristollambretta.com/26mmphbhjets.htm
Tony
I use Beedspeed most of the time and they seem to have the bits I needed, dropped down to the AS 264 atomiser and bought the 48 & 42 idle jet, they had nothing in-between & re-ordered what I think the needle size was X2.

Cheers Gary

[tonydevon]

I understand that people have preferred suppliers, but if your buying a good number of items its well worth shopping about, ordered about 7 times from Wasp, always next day delivery, always what I ordered.

I think when I started out I ordered 264 266 and 268 atomiser, then 5 or 6 needles, about 15 main jets and 4 or 5 pilots, the cost difference was quite substantial with that many bits

[Jack221]

I found this on google which was very usefull especially the pdf manual.
http://www.bristollambretta.com/26mmphbhjets.htm
Tony
I use Beedspeed most of the time and they seem to have the bits I needed, dropped down to the AS 264 atomiser and bought the 48 & 42 idle jet, they had nothing in-between & re-ordered what I think the needle size was X2.

Cheers Gary

These kind of guides are a good place to start jetting. You can see in these a 50 idle jet isn't too much but you certainly won't need any bigger than 50 for yours.

The difference between the diameter of the atomiser and diameter of needle comes into play as soon as the throttle is off the stop. At half throttle you select the needle taper and clip position to run with the atomiser you have already chosen, not the other way around.

An AS264 is 2.64mm inside, an X2 needle is 2.50mm diameter at the top. Difference is 0.14mm. Adjust this differance with atomiser or needle to be richer/leaner from near closed up to 1/4 throttle. Keep an eye on the splooge and feel how it runs.

[GLscoot]

Just really wanting to update on the progress of this post. Having fitted the cir clip at its highest position on the needle and changed the flip choke, the scooter seems to be running ok, although I have not had a chance to use it for work or in the city, where it was causing me the problems. Most of my riding this week has been on longer journeys. Hopefully next week Ill get back to my usual riding conditions and see if its still ok.
cheers gary

[GLscoot]

Just really wanting to update on the progress of this post. Having fitted the cir clip at its highest position on the needle and changed the flip choke, the scooter seems to be running ok, although I have not had a chance to use it for work or in the city, where it was causing me the problems. Most of my riding this week has been on longer journeys. Hopefully next week Ill get back to my usual riding conditions and see if its still ok.
cheers gary

That didn't work, so changed atomiser to 264 and jet to 48, cir clip still at the highest point on the needle, will let you know how this set up turns out.
Gary