I learned to steal

One of my first days as an apprentice cabinet maker, (yes, I am a lowly serf ) one of the masters came to me and said, "You need to learn how to steal". I was shocked to hear this and it showed on my face. Then Paul finished his sentence,.... "with your eyes!!" He said that Alfred who I was assigned to help was a master and I should watch carefully and steal with my eyes because eventually, I would be expected to do everything that he does without any help from anyone or I would be out the door.... Well, I did learn incredible stuff from Alfred, but Paul's comment crosses all lines of mastery, so I try to pay attention and steal from the many knowledgeable people I meet in real life and who's ideas I read here...

My latest bit of theft is from Concours, who keeps saying not to poke the amal pressed in jet with a guitar string, but buy the mini drill set and epoxy the correct sized tiny drill bit into a spray can straw so you can "hand" drill out the pilot jet in order to keep them clear and ensure the idle air circuit works flawlessly... (idle jet clogging or partial clogging being a hard to fix but common problem) So here's the Dr Suess pictorial

You buy these, but the stylus can not reach far enough down the idle air screw passage to drill the jet. You find the proper size bit for the jet you have and move to the next stage:


You find an unused can of something with a clean straw attached to the side of the can, mix up some JB weld or similar and assemble your magic wand thusly.



Never being satisfied with a single magic wand, I made a double so I can drill it out in stages for the least chance of breaking the bit or the wand while clearing the jet. The line you see where the tape is placed on the wand indicates the full depth of the port including passing through the jet. You also check the wand length once you're done drilling the jet with the paper so you know that the wand did not break off in the jet... Super important to know that what you stuck in the jet, comes completely back out of the jet... Here's my double wand below.



I let both wand assemblies cure over night to make sure they are solidly held. Like most of you, I have lots of extra parts. Some years ago I wanted to inspect the mixing chamber on a carb so I removed the welch plug which you can see in the photo below. I also pulled out the pressed in jet.... (I'm way too curious for my own good) But you can see that I placed the tape where I know the wand and bit are fully inserted when the tape is flush with the opening. This is so you can gauge your resistance when you insert your wand. (which if it fixes your crappy idle does indeed make it a magic wand) You want to observe the depth by looking at the tape position and gently twirl the wand with little push and pulls until it's feels smooth. You could put a tiny bit of oil or carb cleaner too, but I would go very light on the oil if you use that. Here's the way I determined where to put the tape.



Don't forget to poke both the mixing chamber holes from the inside of the carb so the fuel can flow out of the mixing chamber holes at idle. Thanks Concours for always adding the comment about making a magic wand out of a mini drill to clear the idle jet. It works much better than a guitar string...

Stealing with your eyes is not silly. If I go to a road race meeting and see a rider significantly out-perform others, I usually go and look at their motorcycle. There is a lot of bullshit in road racing, and old tuners such as Herb Becker do not usually spill their guts. It would be interesting to know what was done to the isolastic mounts on Doug MacRae's Commando.
When we try to keep-up with the fast riders, we often believe it is them who is fast, because we do not know how good their bikes are.
I did not know what a real race bike feels like until I rode a genuine Manx. I could ride that faster than most other bikes, even when it is slower.
My mate said it was slow because he hosed it off when it's owner was riding it. Its owner was a wealthy racing-car driver, who immediately crashed it. The rider adjusts to the bike.

I hated school and what I learned went in one ear and out the other as soon as I turned 15 I was out the door, had been wagging school to work with my dad and worked with him after I left school but after 12 months after leaving school his work started to dry up so had to go get a real job lol.
The first real job was working in an electro plating factory I was washing the chrome when it came out of the chrome tank but wasn't a very healthy environment with all the cancer causing products and looked for another job, did a few years making furniture and steel bending on a mandle bending machine , then I got a job in 82 working at my local Tec College (TAFE) now that is where I started to learn things working as a steel cutter then in the maintenance Fitters workshop as a T/A I was doing a few night courses to improve my skills, I did learn much off the head tradesman Fitter, in fact he was bad at his job, but our young apprentice was very skilled at what he did and he became our major tradesman after he got his ticket and another young tradesman who came alone after the other one left, I learned a lot off these 2 young tradesmen and once our daily jobs were done we did our own jobs and for others as well, I leaned skills on the lathes and milling machine and every other machine as being the T/A I did all the maintenance on the machines.
My head on my Norton was shave on the milling machine, the motorcycle section did the rebore and port work on my head, my crank and cam were sent out for that work.
Well 31 years at the Tec College before taking a redundancy at 55 and retired early, but over those 31 years I built my big shed/workshop up the back and the last 10 years at the College they moved the machine shop to another college so my T/A job came to a end and I become a general hand/truck driver for the college, I learn a lot of good skill from the tradesmen and teachers I worked with, my welding teacher was an ex ship builder in the UK and another welding teacher worked on pipe lines.
I been retired for 11 years but I still have 13 months before I can get the old age pension and now I have to do voluntary community work to get my centrelink payment so I am working at our local Mens Shed a non profit community base, 80% of the work is carpentry but they also have a machine shop and welding shop and the best thing they have a big Bridgeport milling machine that I am sure going to put to good use when I start back on the project bike, they don't mind if you do your own jobs as long as you not selling it off and one of my ex Fitting teaches is also working there, I got to do 30hr per fortnight and so far been making wooden flowers that they sell they can't make enough as they very popular, help to pay for materials we use, I have only been there just over 2 weeks and love it and learning more skills.
The university of life, you never stop learning and never too old to learn.

Ashley

It was called Night School in my day and I learned welding there. What was interesting was a lot of people paid the fee and took the course merely so they could use the tools. The teachers never seemed to mind.

o0norton0o said:

One of my first days as an apprentice cabinet maker, (yes, I am a lowly serf ) one of the masters came to me and said, "You need to learn how to steal". I was shocked to hear this and it showed on my face. Then Paul finished his sentence,.... "with your eyes!!" He said that Alfred who I was assigned to help was a master and I should watch carefully and steal with my eyes because eventually, I would be expected to do everything that he does without any help from anyone or I would be out the door.... Well, I did learn incredible stuff from Alfred, but Paul's comment crosses all lines of mastery, so I try to pay attention and steal from the many knowledgeable people I meet in real life and who's ideas I read here...

My latest bit of theft is from Concours, who keeps saying not to poke the amal pressed in jet with a guitar string, but buy the mini drill set and epoxy the correct sized tiny drill bit into a spray can straw so you can "hand" drill out the pilot jet in order to keep them clear and ensure the idle air circuit works flawlessly... (idle jet clogging or partial clogging being a hard to fix but common problem) So here's the Dr Suess pictorial

You buy these, but the stylus can not reach far enough down the idle air screw passage to drill the jet. You find the proper size bit for the jet you have and move to the next stage:
View attachment 116566

You find an unused can of something with a clean straw attached to the side of the can, mix up some JB weld or similar and assemble your magic wand thusly.

View attachment 116567

Never being satisfied with a single magic wand, I made a double so I can drill it out in stages for the least chance of breaking the bit or the wand while clearing the jet. The line you see where the tape is placed on the wand indicates the full depth of the port including passing through the jet. You also check the wand length once you're done drilling the jet with the paper so you know that the wand did not break off in the jet... Super important to know that what you stuck in the jet, comes completely back out of the jet... Here's my double wand below.

View attachment 116568

I let both wand assemblies cure over night to make sure they are solidly held. Like most of you, I have lots of extra parts. Some years ago I wanted to inspect the mixing chamber on a carb so I removed the welch plug which you can see in the photo below. I also pulled out the pressed in jet.... (I'm way too curious for my own good) But you can see that I placed the tape where I know the wand and bit are fully inserted when the tape is flush with the opening. This is so you can gauge your resistance when you insert your wand. (which if it fixes your crappy idle does indeed make it a magic wand) You want to observe the depth by looking at the tape position and gently twirl the wand with little push and pulls until it's feels smooth. You could put a tiny bit of oil or carb cleaner too, but I would go very light on the oil if you use that. Here's the way I determined where to put the tape.

View attachment 116569

Don't forget to poke both the mixing chamber holes from the inside of the carb so the fuel can flow out of the mixing chamber holes at idle. Thanks Concours for always adding the comment about making a magic wand out of a mini drill to clear the idle jet. It works much better than a guitar string...

Click to expand...

Going to take the lazy path here and ask, that although it's probably been posted previously, what is the correct drill size to clear the amal pressed in jet? I have used the guitar string method previously. Nice tip/trick about using the spray straw.

On the amal website it says a #78 drill which they have spec'd at .016" for Mk I 900 series carbs. I have early carbs so I have the #17 jets in mine which would use the #78 bit. I also read some really interesting info where Greg was mentioning that all 900 series carbs would idle better with a #19 jet and they are probably a larger opening than the many original carbs have, and would take a larger bit to ream the pilot jet. I was thinking of actually drilling out my pilot jets to the #19 jet size... but other priorities are in the way of my life of leisure...


I recall reading somewhere that Concours had already tried that and it worked pretty well... As a rule of thumb, it was mentioned that if your idle air screw is less than 1 full turn out from closed that you should clear the jet and if that doesn't change the setting to greater than 1 turn out, then you should have the next size larger jet. (which I am thinking of drilling mine out after I do a little back and forth with some smart people)

o0norton0o said:

On the amal website it says a #78 drill which they have spec'd at .016" for Mk I 900 series carbs. I have early carbs so I have the #17 jets in mine which would use the #78 bit. I also read some really interesting info where Greg was mentioning that all 900 series carbs would idle better with a #19 jet and they are probably a larger opening than the many original carbs have, and would take a larger bit to ream the pilot jet. I was thinking of actually drilling out my pilot jets to the #19 jet size... but other priorities are in the way of my life of leisure...


I recall reading somewhere that Concours had already tried that and it worked pretty well... As a rule of thumb, it was mentioned that if your idle air screw is less than 1 full turn out from closed that you should clear the jet and if that doesn't change the setting to greater than 1 turn out, then you should have the next size larger jet. (which I am thinking of drilling mine out after I do a little back and forth with some smart people)

Click to expand...

Not to get into a whole carb tuning dicussion here, but you are talking about the pressed in idle jet, correct? Although I've never done it, I'd assume these would be (very?) difficult to change/replace.

I was thinking about drilling the #17 jet out to a bigger size... to the size of the #19 idle jet possibly. I have removed the pressed in jet in one of my extra carb bodies by drilling it out and threading it, then pulled it out with a bolt.

The current set of carbs which I am using now have the idle jet passage drilled out on the back side of the carb so I could clear and inspect the jet from behind it... I threaded the hole I drilled and used locktite on a set screw to seal the hole that I drilled. I could easily drill out the jet from the backside by just pulling the set screw. I just need to chose a size drill to make the jet bigger...

If you follow the logic (which was mostly from a comment that Greg made about idle jet sizes for 900 series carbs, from which I believe that Concours drilled his pilot jets out to a larger size to make his idle better) the larger pilot jet requires a more open idle air screw to adjust the A/F ratio,..... but that larger idle jet also increases the volume of the idle circuit so it's a stronger idle circuit, and less prone to fuel starvation based on it's greater volume.... One of the determinants that indicate "too small" of a idle jet size, is where your idle screw position works best. If it's less than a full turn from completely closed, then the jet is too small (or clogged) and the whole circuit would benefit from a larger idle jet and consequently more turns out of the idle air screw to compensate for the increased jet size..... Make sense??

When I was in high school, I always had 2 jobs in the evening, so I could afford to buy old motorcycles. I was always an excellent student, however I refuse to learn bullshit by rote. Everything needs to be in context. After I failed half of my Matriculation exams I got a job in the public service, and after a year, went back to night school. As a result I ended-up working in laboratories being trained to do chemical analysis. At the time I gained my first diploma, I moved into running laboratories in defence factories. At about the same time, I began road-racing motorcycles. I can drive a lathe and a milling machine, as well as a fully computerised spectrometer analysing metals. I have brought one private engineering company through to ISO9000 certification.
For me, motorcycles are about having fun. However the fun seems to have died with my old mate. With him, there was an agreement - 'no punching above the shoulder', because he only had one eye.
He did not seem to ever worry about dying or police.

o0norton0o said:

I was thinking about drilling the #17 jet out to a bigger size... to the size of the #19 idle jet possibly. I have removed the pressed in jet in one of my extra carb bodies by drilling it out and threading it, then pulled it out with a bolt.

The current set of carbs which I am using now have the idle jet passage drilled out on the back side of the carb so I could clear and inspect the jet from behind it... I threaded the hole I drilled and used locktite on a set screw to seal the hole that I drilled. I could easily drill out the jet from the backside by just pulling the set screw. I just need to chose a size drill to make the jet bigger...

If you follow the logic (which was mostly from a comment that Greg made about idle jet sizes for 900 series carbs, from which I believe that Concours drilled his pilot jets out to a larger size to make his idle better) the larger pilot jet requires a more open idle air screw to adjust the A/F ratio,..... but that larger idle jet also increases the volume of the idle circuit so it's a stronger idle circuit, and less prone to fuel starvation based on it's greater volume.... One of the determinants that indicate "too small" of a idle jet size, is where your idle screw position works best. If it's less than a full turn from completely closed, then the jet is too small (or clogged) and the whole circuit would benefit from a larger idle jet and consequently more turns out of the idle air screw to compensate for the increased jet size..... Make sense??

Click to expand...

It makes sense. When I tune, I start rich then lean-off until the motor misses, then richen very slightly until the miss disappears. Best power is always very close to too lean. I do not believe a normal Amal carb can get there when using petrol, unless it is a real fluke. That pilot jet first appeared in Mikuni carbs which were used on two-strokes. It also works when the throttle snaps closed and provides fuel to stop seizures. When a two-stroke seizes, it is usually at the end of a long straight. With a four-stroke, it is less important.
When I was a kid, none of that stuff ever mattered- we always knew better.

I was pleasantly surprised when I found the 6D Mikuni needles made a difference to the way my 850 accelerates. With slower taper needles, the mixture does not richen so quickly as the throttle is opened. The slightest bit too rich slows the motor, even though you might use more throttle.
I got into the habit of feeding the throttle on by riding a two-stroke. It is a quicker way to go.

o0norton0o said:

I was thinking about drilling the #17 jet out to a bigger size... to the size of the #19 idle jet possibly. I have removed the pressed in jet in one of my extra carb bodies by drilling it out and threading it, then pulled it out with a bolt.

The current set of carbs which I am using now have the idle jet passage drilled out on the back side of the carb so I could clear and inspect the jet from behind it... I threaded the hole I drilled and used locktite on a set screw to seal the hole that I drilled. I could easily drill out the jet from the backside by just pulling the set screw. I just need to chose a size drill to make the jet bigger...

If you follow the logic (which was mostly from a comment that Greg made about idle jet sizes for 900 series carbs, from which I believe that Concours drilled his pilot jets out to a larger size to make his idle better) the larger pilot jet requires a more open idle air screw to adjust the A/F ratio,..... but that larger idle jet also increases the volume of the idle circuit so it's a stronger idle circuit, and less prone to fuel starvation based on it's greater volume.... One of the determinants that indicate "too small" of a idle jet size, is where your idle screw position works best. If it's less than a full turn from completely closed, then the jet is too small (or clogged) and the whole circuit would benefit from a larger idle jet and consequently more turns out of the idle air screw to compensate for the increased jet size..... Make sense??

Click to expand...

The short answer, yes. The topic of carb tuning can become a whole book of info and discussion and debate, for those more experienced and way smarter than myself. I am far, far from being any expert or authority, and certainly don't pretend to be. I've tweaked a fair number of carbs in my time, and am usually just searching for that balance to where they will start easily, idle and run well and not worry about gaining that 1 tenth of 1 percent of improvement over everybody else. One has to keep in mind or remember that when tweaking the magical mixture screw, is the one on your carb regulating air or fuel? On many carbs you're regulating the amount of fuel, whereas on these carbs you're regulating the amount of air, so you, in a sense have to kinda think about the adjustment in reverse as compared to a lot of other carbs.

The important thing in my long winded post was that the idle jet size and the idle air screw position have a relationship,... and as Greg or Concours pointed out in another thread, If your "best" air screw position is less than 1 full turn out from fully closed, you probably need the next size up jet (or maybe your jet is partially clogged....

So, If your idle air screw is turned in that much to give you a proper A/F ratio, then your fuel volume is also greatly reduced which is problematic for a strong idle......So, as was suggested, a bigger idle jet will increase the fuel volume giving a stronger idle and consequently you'll need to open the idle screw position to achieve the proper A/F ratio....

So when your bike idles strongly and your idle air screw position is around 1.5 turns out from closed that's a good sign that you have the optimal idle jet size for your carb..... and if it's only 3/4 of a turn out to idle well, you would benefit from a larger idle jet opening... whether you drill the pressed in jet or removed it and mounted a jet on the port where it meets the float bowl.

When talk of tuning/tweaking carburetors comes up, it reminds me of something that was said (I believe) by an old, savvy, famous mechanic in the auto racing world, Smokey Yunick, that compared to modern fuel injection, using a carburetor is like trying to meter fuel with a toilet. I/we realise that's what was available at the time, but when you stop to think about it, in a way he's right. They're dependent on gravity, vacuum, and atmospheric pressure to operate. Anyway, I remember that saying and thought it was funny.

quawk said:

When talk of tuning/tweaking carburetors comes up, it reminds me of something that was said (I believe) by an old, savvy, famous mechanic in the auto racing world, Smokey Yunick, that compared to modern fuel injection, using a carburetor is like trying to meter fuel with a toilet. I/we realise that's what was available at the time, but when you stop to think about it, in a way he's right. They're dependent on gravity, vacuum, and atmospheric pressure to operate. Anyway, I remember that saying and thought it was funny.

Click to expand...

It took me a long time to get real sense out of carburetors when using methanol. Petrol is twice as difficult because the jets deliver half as much fuel. When Australian riders went to the UK in the1950s to race, they found the British riders could get their Manx Nortons going as fast on pool petrol, as riders could in Australia using methanol. Methanol hides-up the tuning errors. Methanol has about 0.8 times the calorific value of petrol. Carburetors are a British invention - like cricket. - Designed to drive you insane !
For racing, I suggest Amal needle jets need to be calibrated with reamers, using a bottle of nitrogen and a flow meter.

quawk said:

When talk of tuning/tweaking carburetors comes up, it reminds me of something that was said (I believe) by an old, savvy, famous mechanic in the auto racing world, Smokey Yunick, that compared to modern fuel injection, using a carburetor is like trying to meter fuel with a toilet. I/we realise that's what was available at the time, but when you stop to think about it, in a way he's right. They're dependent on gravity, vacuum, and atmospheric pressure to operate. Anyway, I remember that saying and thought it was funny.

Click to expand...

The problem I find with fuel injection and ECUs is the ability it gives manufacturers to meet emissions regs by leaning the fuelling to the point the throttle response becomes unpleasant, particularly on low throttle openings. Not all bikes, but I've had some shocking experiences with a Ducati 1098 and Kawasakis (especially. Z900RS), which seemed to have a mind of their own. It was generally possible to get the fuelling remapped, either in the ECU or products like PowerCommander. I understand manufacturers are being compelled to prevent this in future. As a consequence, I feel happier just cleaning my carbs.

Self confessed Luddite.

Mart UK said:

The problem I find with fuel injection and ECUs is the ability it gives manufacturers to meet emissions regs by leaning the fuelling to the point the throttle response becomes unpleasant, particularly on low throttle openings. Not all bikes, but I've had some shocking experiences with a Ducati 1098 and Kawasakis (especially. Z900RS), which seemed to have a mind of their own. It was generally possible to get the fuelling remapped, either in the ECU or products like PowerCommander. I understand manufacturers are being compelled to prevent this in future. As a consequence, I feel happier just cleaning my carbs.

Self confessed Luddite.

Click to expand...

I think if your old like me, you'll always feel more comfortable with carbs. That's what we grew up with and they were around for many years, and you sort of figure out how they work. But, just 'cause I'm old, I'm not beyond still trying to learn and update and expand my skills. As my winter project here in the frozen midwest U.S., I did an LS engine (fuel injected) and electronic transmission swap into my '57 chevy. A big change and huge difference from the old carbureted "small block chevy" and 4-speed. That may mean nothing to the U.K. members here but that was the traditional powertrain for an old hot rod. Anyway, instant starting, perfect idle, instant throttle response and even better mileage have made me a believer. More 'topic drift". Sorry.

After 50 + years with dirt bikes, and British motorcycles to old cars all running carbs and since 2013 buying my first new Triumph Thruxton 900 and my new 2016 Thruxton 1200S, when I sold the 2013 Thruxton I had clocked up 50K on it and not once did I even look at the injectors or the ECU and so far am just coming up to 40K on the 1200 and the first few weeks I did the Meekat x-pipe and opened up the stock mufflers, the first ride the bike ran very lean but after a 20 minute ride and shut down the ECU did the adaption for the change to the exhaust system and has run prefect every since, the ends of the muffler run a lovely colour and not lean or over rich, in fact runs prefect, in that time I haven't even looked at the plugs, the ECU did everything.
How often you muck around with old Amal carbs after change and re jetting to blocked pilot jets and all, to worn out slides/jets and needles, float levels and it all goes on.
Keep up with the times as I hear it all the time from old mates who just don't want to trust new Tecnology or scared of it, they are old school who don't like changes, but I am old school in everything I do in life but I love my Thruxton where I can jump on it any day and just ride, I jump on it tomorrow and do a 3k km round trip without doing a thing except maybe throw some chain lube on if it needs it, I am not scared of changes.
Over all my years of working and learning I have stolen a lot of ideas but improve on them ideas to work best for me and if someone likes what I do and they want to steel my idea well good on them, just make a few changes so it's not the same as mine lol.

Ashley

ashman said:

After 50 + years with dirt bikes, and British motorcycles to old cars all running carbs and since 2013 buying my first new Triumph Thruxton 900 and my new 2016 Thruxton 1200S, when I sold the 2013 Thruxton I had clocked up 50K on it and not once did I even look at the injectors or the ECU and so far am just coming up to 40K on the 1200 and the first few weeks I did the Meekat x-pipe and opened up the stock mufflers, the first ride the bike ran very lean but after a 20 minute ride and shut down the ECU did the adaption for the change to the exhaust system and has run prefect every since, the ends of the muffler run a lovely colour and not lean or over rich, in fact runs prefect, in that time I haven't even looked at the plugs, the ECU did everything.
How often you muck around with old Amal carbs after change and re jetting to blocked pilot jets and all, to worn out slides/jets and needles, float levels and it all goes on.
Keep up with the times as I hear it all the time from old mates who just don't want to trust new Tecnology or scared of it, they are old school who don't like changes, but I am old school in everything I do in life but I love my Thruxton where I can jump on it any day and just ride, I jump on it tomorrow and do a 3k km round trip without doing a thing except maybe throw some chain lube on if it needs it, I am not scared of changes.
Over all my years of working and learning I have stolen a lot of ideas but improve on them ideas to work best for me and if someone likes what I do and they want to steel my idea well good on them, just make a few changes so it's not the same as mine lol.

Ashley

Click to expand...

Getting further "off topic" here but in response to your post, the LS/Vortec (injected) engine I swapped into my '57 had around 130,000 miles on it in the truck it came out of, but when I swapped I even used the spark plugs that came in it and it runs perfectly. Like you say when some of my buddies (old guys like me) heard I was going to do the swap they seemed to act like I was attempting to launch the space shuttle. They're stuck in the 50-60 years ago world and want to be able to fix things with a screw diriver and a crescent wrench. Carbs will always have their place on vintage bikes and cars, but even us oldsters ought to keep an open mind about moving on and injection. I'd bet the car they're driving has modern fuel injection.

Modern technology does not worry me, because I know there is no system which cannot be defeated. The best fun is when you get a computer to programme itself. My offsider told me I should not be doing that. In the old days, we had an ASR33 teletype which produced a punched papertape - the user programmes were also on punched paper tapes. The computer can create a paper tape which can be fed back in, to programme it. There is probably a modern-day equivalent. Then there is a question about whether computers can have self-determination. It is all really quite funny, The whole thing can be made to disappear up it's own bum.