i just bought a new sirio xxx .12 after being a long time OS user.

the engine has about 15 tanks through it.

the engine runs great - temperature is fine, nice trail of smoke down our straight, and it will idle for over 1 minute and take off great with no bog down.

the problem is, it idles on straight after full throttle.

for example, after going down our straight full throttle then braking for our turn, it idles high and takes like 3-4 seconds before it idles down.

if im holding the car in the air, and i open full throttle for a few seconds, then close it fully, it will idle high for a few seconds before it drops.

if i richen the bottom end any further, it will stall. if i lean the bottom end any more, it begins to hesitiate from a standing start.

if i try the pinch test, i squeeze the fuel line fully, it revs up very highly for a few seconds before dying.

any suggestions???

i would say.....
richen your lsn slightly and open your idle gap slightly to compensate..
as long as your revving slightly and getting about a 3-4 second count before it dies,then your golden. it shouldnt pull when you pinch the line,but it also shouldnt just stall either when pinched.

X2

Also make sure to set the LSN so that it loads up at around 15sec.
Having it idle for a minute and going WOT without hesitating even a bit then the LSN is too lean.
When coming of a WOT run let it idle and try to hear the revs...it should start to drop slightly after a few seconds...those few seconds should be around ~15sec...any sooner and it's too rich any longer and it's too lean...always talking about LSN. HSN is supposed to be set right.

If Im not mistaking, its normal for Picco Based and Sirio Based to have a few seconds idling high after coming out of WOT. Its not like Nova based that they are supposed to idle down to idiling revs very fast.

But I agree, if after 1 minute, it should very much hesitate to go WOT. If it doesnt then your too lean on LSN.

That right there is your problem. It should load up after a full minute of idling. You're too lean on the lsn.

I'd have thought the problem is the exact opposite,

Bottom end is too rich , which has to have a high idle speed to compensate - once the engine "clears" after a good rev the idle stays high until it loads up again...

You just proved it to yourself when you squeezed the fuel line, the revs rise up "very highly"

Make sure you add some more fuel to the top end needle to compensate.....

That is a possibility. I say he should try to richen the lsn first. If that cures it, all is well. If it is too rich with a high idle speed then it will not want to idle at all so then lean the bottom and back off the idle.

this is normal both my sirios evo4 and xxx do it and also pritty much every one racing at my home track with a sirio has this problem. mine will sit ideling perfect then you give it some and it will ping for a couple of sec's and return to normal its a sirio thats wat they do