Pilot Jet for 750 ....17 or 19

concours said:
Ain't no fun in that...
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concours said:
Well kids, I concur, it does run better at low rpm, and the occasional tip-in cough is gone. Ended up about 1-5/8 from seated.
Thank you for the reassurance (I respect you kids opinions/findings :cool:
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You should double-check for an air leak. It's almost always between 1-1/4 and 1-1/2 out for the air screw. May just be your specific setup but worth a little more checking.
 
L.A.B. said:
The Premier pilot number is the jet I/D.

https://www.britishmotorcycleparts.co.nz/amal-premier-pilot-jets

"622/502-15-23 AMAL Premier Pilot Jets​


The ID of the standard jet is 0.017” This is the same as the nominal ID of the former pilot bush which was rated at approximately 23cc. The new jets are also available in 15, 19, 21 and 23 sizes which again are measured in thousandths of an inch.

Premier ID Grooves
1 Ring - 622/502-15 (Equivalent to 20 Pilot Jet in pre-Premier carbs.)
2 Rings - 622/502-17 (Equivalent to 25 Pilot Jet in pre-Premier carbs.)
3 Rings - 622/502-19 (Equivalent to 30 Pilot Jet in pre-Premier carbs.)
4 Rings - 622/502-21 (Equivalent to 35 Pilot Jet in pre-Premier carbs.)
5 Rings - 622/502-23 (Equivalent to 40 Pilot Jet in pre-Premier carbs.)"

The screw-in pilot jet number is the flow rate (cc/min).
amalcarb.co.uk

Shop our Pilot Jet - 25cc | 124/026-25 | AMAL Carburetters

Pilot Jet - 25cc
amalcarb.co.uk amalcarb.co.uk
"All genuine AMAL jets are calibrated to a flow rate. The number e.g. 100 indicates that it will flow 100cc`s of fuel in one minute at a specified head."
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I still have two of the screw in jets.
Pilot Jet for 750 ....17 or 19
 
marshg246 said:
You should double-check for an air leak. It's almost always between 1-1/4 and 1-1/2 out for the air screw. May just be your specific setup but worth a little more checking.
Click to expand...
100% sure there is no air leak. I would offer probably personal (fuel mixture) preference.
 
concours said:
100% sure there is no air leak. I would offer probably personal (fuel mixture) preference.
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Oops! Had my head on backwards. No reason to expect air leak when you're giving more than normal amount of air! As long as it doesn't stumble when you blip the throttle from idle, it's just what your bike wants!
 
I was just about to mention THE hobot Memorial Post....
and that those chilling on the deck pix , the Road Inhaler parked in front of the crib are just asking
for a thread on exactly those pix from the rest of the clan.
After all if , FE gets to bust on Jimbo for showcasing those cast wheels, then we can all get flamed for
My Zone Exceeds Yours....
 
Just saying that the photo of that fine, fine, superfine, relaxation area on the lake and the swank massive three cylinder monster ups the ante and we need a thread showing other well located and endowed zones of our members. FE was commenting on the cast wheels as "showing off". Yes, I know this was in jest same as my
calling out those with the well situated zone. No offense intended!
 
Onder said:
Just saying that the photo of that fine, fine, superfine, relaxation area on the lake and the swank massive three cylinder monster ups the ante and we need a thread showing other well located and endowed zones of our members. FE was commenting on the cast wheels as "showing off". Yes, I know this was in jest same as my
calling out those with the well situated zone. No offense intended!
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?
Zone....????
I contacted my Aunt & Uncle, for I wanted to visit them. "Sorry, we're away, but please come to the lake & relax. Neighbor has the key."
The premise of my post was: " please stand by, I'll be back to repairing the vintage Notrun shortly, wife & I need some wind therapy before the last vestiges of Summer slip away."
 
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I've recently been having slight intermittent misfire at idle, and also at slight throttle cruise.
Seems like left side.
Fresh plugs, and a new bowl gasket, now for a test ride.
Pilot Jet for 750 ....17 or 19
 
concours said:
I've recently been having slight intermittent misfire at idle, and also at slight throttle cruise.
Seems like left side.
Fresh plugs, and a new bowl gasket, now for a test ride.View attachment 108134
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Maybe:
1) The carbs are not perfectly synced
2) One throttle stop raising the slide slightly more than the other.
3) Left side air screw slightly too far out.
 
marshg246 said:
Maybe:
1) The carbs are not perfectly synced
2) One throttle stop raising the slide slightly more than the other.
3) Left side air screw slightly too far out.
Click to expand...
The air screws were all over the place this spring after layup. O-rings had shrunk. Lose adjust in 1/4 mile, but since I replaced the o-rings, they hold adjustment.
 
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not sure where this threads at, AND CORRECT ME IF I'M WRONG, but i once read that the pilot screw should be in the 1-2 turns out range with 1-1/2 turns being the sweet spot. anything less than 1 turn, you need a smaller pilot jet - more than 2-turns, a larger pilot jet. IS MY UNDERSTANDING CORRECT OR DO I HAVE THINGS BASS-ACKWARDS? i'm thinking as you turn the screw in, you're restricting AIR in the pilot circuit - turning the screw out, increases AIR in the circuit. right-wrong-??? note - i'm by no means an amal expert.
 
joe czech said:
not sure where this threads at, AND CORRECT ME IF I'M WRONG, but i once read that the pilot screw should be in the 1-2 turns out range with 1-1/2 turns being the sweet spot. anything less than 1 turn, you need a smaller pilot jet - more than 2-turns, a larger pilot jet. IS MY UNDERSTANDING CORRECT OR DO I HAVE THINGS BASS-ACKWARDS? i'm thinking as you turn the screw in, you're restricting AIR in the pilot circuit - turning the screw out, increases AIR in the circuit. right-wrong-??? note - i'm by no means an amal expert.
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Think of it this way. The pilot jet flows a fixed amount of fuel more-or-less no matter what you do with the pilot air screw. When you turn it in and out, you are changed the air/fuel mixture by changing the amount of air that is mixed with the fuel passed by the jet. According to Amal #17 is correct for 750 Nortons and #19 for 850 Nortons. Generally speaking no matter which you should start out 1-1/2 turns out and something is wrong if you need more on a stock bike. Usually, you'll end up at 1-1/4 or a little more - no matter #17 or #19. That said, using a #19 and setting the air/fuel mixture correctly will get you more air/fuel at idle and I (any many other here) recommend #19 for Commandos and I've found them best for 650/750 Bonnevilles and for Tridents as well.

Assuming accurately sync'ed carbs, identically set throttle stop screws and no air leaks, the bike should idle anywhere between 1-1/4 and 1-1/2 turns out. When you blip the throttle, if the engine stumbles, you need to turn the screws in slightly. If you turn them in past 1-1/4 turns you need to fix the air leak.
 
I've noticed that these bikes start easier if you can give them a really hard kick instead of a tired little poke. My theory is that the hard kick increases the suction through the carb drawing up more and better atomized fuel. So...kick hard.
 
seattle##gs said:
I've noticed that these bikes start easier if you can give them a really hard kick instead of a tired little poke. My theory is that the hard kick increases the suction through the carb drawing up more and better atomized fuel. So...kick hard.
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You mean if the bike is a kickstarting bastard?
Never had that problem.
Thanks though.
 

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