idle screw well in, mixture screw does not a lot

[tonydevon]

ok thanks, I get all confused with this advance and retard malarky, time to go and have a right good read up and try to understand it better

safety at higher revs is what Im after long term as I will be facing long A road runs with it, both commuting and to get anywhere outside of Devon.

Im not "too" fussed about huge power etc, just want to be able to keep up with traffic and not get too left behind by the rest of the club, but Im never going to keep up, 225's and TS1's etc

would rather have safe slightly lower BHP than a motor thats at risk, if this blows and needs new top end anytime soon, then Im stuffed.

[CPH Lambretta]

Have a look at this, it helped me alot when I was setting up my Mugello:
http://lambretta.co.uk/downloads/carbjetting.html

[tonydevon]

ok guys I need some advice.

so I went with the 50 pilot and I got an idle with the screw turned out some instead of bottomed

it idles smoothly and will idle very low.

I got it warmed up and can run up the drive in first, but cant open the throttle.

its the same at idle on the stand.

open the throttle up a very small amount and its fine possibly a little wooly, revs drop back to idle no problems

the issue is when you try to open it up and rev it, just goes BLLUUUURRRRRRRRRRRRR, try a full throttle opening and it almost sounds like its pulsing slightly

cant actually ride it up the road.

I tried putting an air filter that I have spare over it, a bike raimair one, no improvement, tried introducing the choke, worse. so I am assuming that its rich?

I have main jet 125 as recomended above.

I have the following atomizers and needles, what would people advise I try?

AV264
AV266 *fitted
AV268

X2
X7* fitted, second groove from top
X13

also have fitted 300 float needle valve

many thanks in advance, I apologise for all my questions, but havent a clue about what Im doing LOL

[tonydevon]

I have just gone back out and tried it again, introducing choke doesnt improve the open throttle situation, and tried a bit more restrictive air filter this time, but no joy

Im running open carb.

so I been playing detective on the net and from my findings the needles run weak to rich, X7 X13 X2, so I have the weakest needle in there already

atomisers weak to rich are 264 266 268, so would it be correct theory to run the AV264 with the X7 needle? or do the needles and atomisers have specific pairings.

Im concerned that I seem to be looking at the lean ends of jetting

[nelson pk]

Hi Tony
Sounds like its over rich to me but it is difficult to tell on a forum. First thing to establish is........is it rich or is it lean?
First i would check fuel flow from tank to carb just to make sure and be safe (should flow at least 1 pint in 1 minute from memory i think) and take the float bowl off the carb to make sure the floats and needle valve are operating correctly.
Check the float height as well by taking the float bowl off and then resting the carb on the bellmouth side and measure between the surface that the float bowl mates to, to the top of the floats. It should be 23.5mm plus or minus 1mm from memory.
If everything there is fine its pretty much definite that its a jetting issue.
It sounds like its getting worse as it gets to wide open throttle so it could well be a main problem.
So then if it were mine i would get a 118/120 main and a 130 main and see which makes it better. This will tell you if its rich or lean.
Warm it up and then run it on the stand and do the same test that you have been with those different jets.
Once you can get it rideable you can start to jet by ride/feel and choke tests and plug chops.

[tonydevon]

many thanks Nelson and the others that have taken time to try and help me

I am now thinking that this might be electrical issue

this forum is very helpful and much appreciated, especially when your as new as I am.