Linkert fixed jet

[charles]

Hi,
I have Panhead of 1951, always with his Linkert which I have much difficulty of adjusting since I dismounted it for a cleaning. The fixed jet is #19 , I think that the diameter is too important, at any beginning of acceleration I have detonations in the carburetor with light-backs, as if there were too much gasoline to arrive at the same time and/or pre-ignition . Ignition is OK. No air leak. the idle is OK. I Would like to know if I change the diameter for a #17 il will change something?

[Cotten]

Charles!

How are you certain that you have no air leak?

....Cotten

[charles]

Indeed not certain! air leak can cause this kind of disorder. In fact, dice which I open the accelerator (at any beginning of acceleration), there are detonations and light-back in my carb. As if ignition were done too early. I remember to have read on a post that could arrive with a too important jet, and gasoline arrive too much, and to pass in #17 could be a solution?

[Cotten]

Charles!

Before changing carb variables, let us eliminate the airleak variable first.
A large stopper with a hole in it works just fine (if you have three hands): http://virtualindian.org/11techleaktest.html" onclick="window.open(this.href);return false;
Even the tiniest blisters of foam that might take a minute to appear can still affect tuning and optimum performance.
Test also the pan cover screw over each intake port, as occasionally they breach.
If you find NO leaks, don't fix it.
We shall instead discuss your float next.

...Cotten
PS: By the way, is there a collar under the Lowspeed needle spring?