Templar M Stuttering

Megadan · 05-06-2024, 12:49 AM

Quote:

Originally Posted by ProDigit

in some cases the af screw adds fuel but doesn't help much
It only aggravates the idle. Like it's fighting the idle screw.
On mine, I just closed off the af screw on mine.

That's because it's not really the A/F screw. It's the idle mixture screw, which is why it mainly affects idle. Using it to correct anything other than idle fueling is the wrong use of that screw.

There are two idle adjustments. Curb Idle speed, aka idle rpm, and idle mixture, aka the actual fueling of said idle. Both generally need to be adjusted together, and only adjusted with the engine fully up to temp. You start with setting the curb idle speed to a slightly higher than normal idle, and then adjust the idle mixture in (on a PE) to find where the idle drops from being a bit too rich, and then back it out a bit at a time until you discover the highest steady idle speed away from that bog point. Then lower the idle rpm to where it should be, usually on these small singles it will be 1500rpm plus or minus 100 rpm.

If at any point the idle increases during your adjustment from where you first set it, lower it back to the rpm you set it to when you started.

If you go less than 1 turn in and the idle doesn't change at all you are too lean (PE carb idle mixture adjusts air) and likely need to go up a couple points or so on the pilot jet, which directly affects the idle circuit.

If you have an unsteady idle and find yourself backing out the idle mixture more than about 2 to 2.5 turns, your pilot jet is too rich and you need to go down a couple points or so.

I always advise to adjust the idle mixture first, and specifically because it's affect on the rest of the throttle sweep is minimal to almost nothing. The pilot jet has the biggest effect on part throttle, up to 1/8 mostly, and maybe about half up to 1/4 throttle. The easiest way to judge if the pilot is a little too big or small is to hold about 1/8th throttle at a steady speed. If it hesitates, bucks, or bogs, adjust appropriately.

Leave the needle in the middle slot on the adjustment as it will be the last adjustment you will want to make since it is affected from both ends by the pilot circuit and the main jet size.

The main jet should be the next jet adjustment. The easiest way to judge the main jet is to do a plug chop after running WOT for a decent length of time so you can freeze frame the fueling on the plug color. Ideally you will want a light to medium tan color on the porcelin. If a plug chop isn't for you, you can also judge the main jet simply by how the bike feels, with the simplest method being to go up a full size at a time until you start to hear/feel it bog down and cut out, and then back off a size. Example - When I first installed the exhaust on my first Hawk, I already had a 110 main jet. To be safe I installed a 120, and it immediately would start bogging out and cutting out from how rich it was. I backed off to a 117.5, but it still felt a bit sluggish. Put in the 115 and it pulled strong to redline. A plug chop showed my plug a nice khaki color, which was perfect.

Only when you know the main jet is good, and your idle and part throttle hasn't changed at all and doesn't need possible adjustment, can you look into adjusting the needle. Now, I tend to try and adjust the needle clip and my idle mixture to be a tad on the lean side of things (in moderate temperatures like 60-70 degrees) - as lean as it can be without causing running issues that is - to try and get my fuel economy as good as I can manage. There is a lot less risk of melting pistons and soft seizures than there is at WOT, so you can get away with it. Plus, being a touch on the lean side in those moderate temps also means when it gets hotter the mixture naturally gets a bit richer. The only downside to that is when i gets colder it may cross over to being a little too lean and then I have to adjust the mixture screw and needle clip position to compensate.