Jetting advice please

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alanscottj
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Main scooter: Lambretta GP SS250 Casa
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Todays jetting :

118 main
45 slide (new)
x7 needle top clip
AV268 atomiser
48 idle jet (new)

This is running much better but mixture screw is all the way in and so is the tick over screw to get a half decent tick over. The scooter starts very smoky but this soon clears when riding. When I'm riding and come off the throttle it returns to tick over ok but again when I come to a crossing, especially if I have come down from 3/4 throttle, she nearly cuts off. So, am I right in thinking that I am still too rich at tick over and need to go down again on the idle jet???

Thanks for all the help up to now :D
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox ๐Ÿ˜Ž๐Ÿ‘
Muppet
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Main scooter: SX 150 running in

266
Cโ€™est la vie
alanscottj
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Muppet wrote:266
Try a 266 atomiser you mean?

I've just re-read your last message :D
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox ๐Ÿ˜Ž๐Ÿ‘
nelson pk
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Agree with muppet. AV266 atomiser. Once you have her ticking over nicely and set air srew, idle jet etc put the needle on the richest position you can get away with without spluttering like a good un in the mid range ......as its in the mid range throttle position (cruising) where most overheating disasters happen.
alanscottj
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nelson pk wrote:Agree with muppet. AV266 atomiser. Once you have her ticking over nicely and set air srew, idle jet etc put the needle on the richest position you can get away with without spluttering like a good un in the mid range ......as its in the mid range throttle position (cruising) where most overheating disasters happen.
I feel a bit of a pleb now, after all your help I have realised that I forgot to say that my Muggy has a reed valve fitted, so with that in mind would that in any way affect the scooter is powering down?

Jetting so far:

53 pilot
128 main
Av 266
X7 top clip
45 slide

Now only runs right with choke on :roll:

I only want to get it running ok so I can get it dyno'd next month.
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox ๐Ÿ˜Ž๐Ÿ‘
storkfoot
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Main scooter: '70 GP150 [TS1 225]
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Are you absolutely sure you don't have an air leak somewhere?
nelson pk
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Reed valves dont tend to.... " put, put, put" when you come off the throttle. They do shut off to tickover very quickly without the "put, put, put" however if it is not going to tickover and the engine is dieing instead......that would tend to indicate a too rich condition somewhere.
If when you shut off the engine is going to tickover without the "put, put, put" that is how a reed valve will act.
alanscottj
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storkfoot wrote:Are you absolutely sure you don't have an air leak somewhere?
I'm going to do a leak down test to rule it out.
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox ๐Ÿ˜Ž๐Ÿ‘
dave411
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Alan,you did mention it at the begining. :)
camel
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Hi
I jetted up a 26 dellorto for a cast iron reed 200 set up using a gamma tech display to obtain good egt temps
Pilot 53
Atom av266
Needle x13 clip 2 from top
125 main
Hope this helps
Camel
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