Engne dies at junctions and traffic lights!

[alanscottj]

I am trying to sort out my jetting. 30mm dellorto with JL3 running through a RamAir filter. It runs nice but when I have to stop at a junction or traffic lights I have to rev it to keep it going, sometimes, even when revving it, it will die. Any ideas? I have a feeling it is something to do with the 'idle' but not 100% sure. HELP!

[cgt75b]

To start with just try turning your tick over screw in a touch. See if that helps

All the best

Lambretta don't you just love em

[alanscottj]

Cheers, I'll give that a try tomorrow:-)

[storkfoot]

I'm guessing you have something near a 300 float needle, pilot 55, AV264 and x13 2nd clip, 125 main

[alanscottj]

I'm guessing you have something near a 300 float needle, pilot 55, AV264 and x13 2nd clip, 125 main

Main is 110, 53 pilot, x4 3rd clip, AV 268 - as supplied and recommended by CamLam

[storkfoot]

I can't really comment on that specific set up. I haven't heard of an x4 being used before. I'm assuming a richer mid range is compensating from what, on the face of it, is a smaller main jet.

Anyway, try adjusting your air screw 1/4 turn at a time. Go in and out as you'll learn the effect it has. If it gets better by richening ie screwing out but is still not ok, go to a 55 pilot.

As an aside do check your float needle valve and don't hold it wide open throttle until you are sure about that jetting. Dyno ?

[alanscottj]

I can't really comment on that specific set up. I haven't heard of an x4 being used before. I'm assuming a richer mid range is compensating from what, on the face of it, is a smaller main jet.

Anyway, try adjusting your air screw 1/4 turn at a time. Go in and out as you'll learn the effect it has. If it gets better by richening ie screwing out but is still not ok, go to a 55 pilot.

As an aside do check your float needle valve and don't hold it wide open throttle until you are sure about that jetting. Dyno ?

I have looked at loads of different set ups on the tinternet and have yet to see another set up with an X4 I will have a go with the air screw today and take it easy on the throttle. I am going to get her dyno'd but still have a few miles to go before it's run in after the engine rebuild (about 500!). Thanks for the tips anyhoo

[coaster]

Have I missed something? there is no mention of what engine this is, Lambretta? Vespa? or capacity/state of tune so how can we be doubting that the set up is wrong

x4 is new to me too.

[alanscottj]

Have I missed something? there is no mention of what engine this is, Lambretta? Vespa? or capacity/state of tune so how can we be doubting that the set up is wrong

x4 is new to me too.

I think Storkfoot has helpes me on another thread where I was more specific on my setup. Which is:

Mugello 198
JL3
Dellorto 30mm
Remote Ram Air

Anyhoo, had a play about today with needles and jets. I am now on:

AV266 atomiser
X7 needle 2nd clip
115 main

Only had it for a short spin but it feels much, much better. Does this look like its about right? It certainly feels and sounds ok. Gonna do some plug chops tomorrow:-)

[storkfoot]

Main jet still looks a bit weak. If you have some bigger main jets, just try them until it starts getting boggy at the top end, then drop to the next lowest.

So, have you sorted the problem with the engine dying at tick over. If so, what did you do?