There was a guy in Michigan named John Twist at University Motors (now closed) in Grand Rapids who was a magician with British cars. He is retired but I believe he still gives seminars and workshops. The next time you have a British car and have questions he would be someone to call. I've owned a couple of MGB's and at first those SU carburetors were intimidating but after watching John's TH-cam videos and some advice from the MG Experience forum I came to love them. I converted one car back from a modern Weber that a previous owner had installed back to SU's and it ran so much better.
SU carburetors are among the best. The Hagerty videos are very engaging, well done and informative. This one is no different. Great job. A side note. Making a custom intake manifold for a Harley-Davidson MC from some aluminum tubing and plate that enables you to affix an SU to your Harley improves performance of your MC quite a bit. Getting it jetted correctly isn’t that hard and it’s worth the effort. I did this many years ago with a 1956 KHK I had. The SU carb and some other improvements I made to its breathing made that rascal run fast.
I LOVE SU carbs! Such a great carb to drive and work with. We ran our class built Datsun 1600 (510) on the Factory Hitachi SUs and loved them 👌 Never went out of tune for rally after rally with the Japanese linkage system.
G'day Hagerty Channel. I am not a professional mechanic as yourselves, but I have been working on Mini's for several decades. Regarding the rebuild of your SU carb's, I would advise you to do a couple of things. - You should do a balance check - to make sure the dashpots fall at the same rate. Now that you've replaced the jets, you might want to consider checking that the jet seats correctly. You may have done all of this off screen, but if not, I'd be happy to take you through this in detail if needed. Getting them balanced and set up correctly will make the tuning process much less painful. Thanks for the great channel. Very entertaining and informative. Cheers.
If you don't happen to have a lathe, chuck that rocker shaft (or whatever you might want rotating to polish/clean) into a drill and do it to it. I've done this on old bicycle axles where there was some pitting on the bearing race cones and it's a good shadetree way of "machining" a surface. Not the most precision way of doing things, but it works for old beaters.
I love the SU carburetor, it's so simple, self metering, easy to tune, and reliable. I've played with many types of carbs and I genuinely think the SU is the best to use. I particularly enjoy the simplicity of the fuel enrichment by pulling down the jet instead if having a choke.
Don't forget the throttle shaft bushings. They wear and leak air making achieving a good idle and balance impossible. There are sealed ball bearing kits available. Moss Motors has a good page on re-bushing the carb bodies. Oh yeah, turn between centers...
Hay David don't forget to stake the butter fly screws. Or some type of lock tight. I had one back out on me . Let say the valve didn't like it very much. That was a early learning experience for me.
My dream would be to hang out with you all and rebuild any car. I'd happily push a broom all day as long as I could absorb the knowledge. I could justify the tools if I had the knowledge, and I'd get the confidence to try more. Also happy you have teamed with Rock Auto. I am happy to give them money compared to A*******n.
I like this channel. My dad has an Austin Healey 3000 mk2. The carbs look the same. It's been being restored for some time. No end in sight. My mom is from Detroit.
Albeit I entirely agree, they probably don't have the time or resources to film for such things often. Not to mention TH-cams viewer retention, for videos that long, usually suffer greatly discouraging creators like Hagerty to produce long elusive content. In my honest opinion most, if not all, of these quick videos show you more than enough to replicate the build process yourself. Chances are if you have this engine in front of you on a stand, you should probably already have done your research on it, which is just a few clicks away these days. From my perspective these videos best serve as a form of commemorating these engines and the legacy of each vehicle while also exposing those who aren't able to have the opportunity to see the innerworkings at such an in-depth level.
The wear on the rocker shaft will cause a decrease in oil pressure. Cheap insurance to just buy a new one. Good thing you did one carb at a time as you cannot mix and match parts when it comes to the piston and suction chambers.
Back in the day, I did a lot of those old A-Series engines and almost never had reusable rocker shaft or rocker bushings.The shafts were pretty poor material and wore out in the 80K miles those engines usually got before needing an upper end overhaul. Maybe that one was replaced at some point.
tHanks for posting Jim. I have loads of these parts that sat for decades. I can't tell what will be able to be saved and what won't. I keep thinking "keep the original" but recognize that may be foolish thinking. For now, I'm just moving crates of parts to better storage.
SU=Skinners Union, a very old English Company. An SU is a very simple carburetor yet reliable and very efficient, they are almost as good as EFI with an SU carb you can NOT over carburate because they use engine the engine sucks in what it needs, mixture is set by adjusting the needle which controls the mixture. An HIF6 SU ( SU, HIF= High Air Flow ) they can flow as much air/fuel as a side draught Weber for a lot less money!
Really, really nice job on those carbs, Davin! I can just imagine what some dude, somewhere, is spending on shipping his SU's back to Jolly Ol' Britain to get redone! I always enjoy your episodes, but because I love Minis, and the engine is so unique for its day, this rebuild is especially fun. Kudos to everyone involved!
I had two SU carbs on a 1969 Volvo 122S. My biggest problem was the bushings on the throttle shaft - if these are worn you have problems with idle mixtures because the worn bushings / shaft form a vacuum leak. You need to a) get new bushings and throttle shafts, b) drive out the old bushings, c) drive in new bushings and most important d) ream those new bushings for an almost zero clearance on the new throttle shaft -the old snug but free business. There were no shaft seals on the old SU carbs I had. Lucky for me a local mechanic had the reamer, because the reamers were a scare commodity. FYI: We used ATF as damper fluid, and not brake fluid as some suggested at the time. A wise owner will clean the dash pots ever fall so as to remove any moisture 'cause they can freeze in the winter time making for a no start condition. Likewise these parts must remain perfectly clean, no dust or dirt to disturb the air bearing area. When they work they are fantastically good carbs!
Been there done that. Though with three! The carbs to use for all you desperados out there is the pre emission carbs with floating needles. You cannot buy a decent needle for the emission carbs for tuning. A heap of needles are/ were available for the non smog carbs. IF set up properly they are near trouble free. Smooth idle though is sometimes an issue. Until recently I had Holden 6s here with triple 45mm Webers and and still have another with triple 1 3/4 SUs. Both on racecars but were very reliable.
I don’t understand the sped-up video segments. Who thinks we don’t want to sit and enjoy watching Davin disassemble and then reassemble each and every little detail of an SU carb?
Whilst in your case you had the opportunity of running the carbs before dis assembly, you should allways check the clearances of the throttle shaft and the body. They are the aquiles heel of the unit as the bronze shaft tends to wear away the aluminium casting on hogh mileage cars leading to rough idle due to air leaks. You can fix that either via oversize shafts or bushings which are relatively easy fixes. Again, in your case probably not a bid deal as the units looked to be in relatively good condition. Presumably you changed the throttle screws (which are withworth threads!) What solution do you use in the ultrasonic cleaner? Keep wrenching! you are the reason I am suscribed to this channel.
Did you check the code on the needle that goes into the jet (against the replacement in the kit) as they are different for many applications, especially if the engine has been modified. Agree on all the comments on the rocker bushes and rocker shaft. You loose a lot of valve lift if there is any wear in these parts...they are so cheap, its simpler to get new / uprated parts like roller rockers
What mesh media do you use for the vapor blast? For the tumbler, try Cascade dish washing detergent, it is non-foaming and non-spotting and you can use any concentration you want.
@@Hagerty The size should be on the drum you get it in. It will be marked as a screen size like 120-200 or a 2 didget number, 120-200 is size No. 11. The higher the number the finer the media just like sand paper
What kind of fit was there on the throttle shafts to the carburetor bodies? My buddy had a 59 TR3 with this same type of carburetors . The first set of carburetors the carburetor bodies the holes were wore out causing a bad vacuum leak. He had to find another set that were much better.
I'm dying to find a place to do vapor honing on my old bikes near me. I'm in MI like I think y'all are, any suggestions? Shoot I'll drive out to Hagerty and do the work myself
How about a minute or two of "here's how the side draft SU's function" when you install them or tune them. I rebuilt twin SU's on my TR-3 and never understood it then or now. I took it to someone to have them tuned and he said "who on earth tuned these last time?'" I just said it must have been the last owner...
Am I too paranoid for marking the rocker arms and then putting them in the same place (as well as the rest assembly)? I was under the impression that parts that worked together for quite some time get unique wear pattern and if you mix them later on it accelerates the wear. Or is it not that crucial?
Is vapor honing suitable for cleaning carburetors? As I understand it, vapor honing is just media blasting with water. Couldn't some of the media get where it's not supposed to be and possibly cause a blockage?
didnt see you check for spindle wear? did you take the spindle out and mic it up? puting back a rocker shaft with wear ridges? is this another half arsed job like knurling valve guides?
I have an old advert with Devin featured as a parts runner If I send it with a return envelope would Devin sign it and send it back? I think it will class up the man cave.
Never, ever fully grip a shaft rotating in the lathe. If that scotchbrite grips it will tear your arm off. Support it from underneath resting on your fingers and use kero or coolant to wash the debris away.
I dunno man, is a carb SU rebuild without rebushing the throttle shafts or at least replacing them really a rebuild? I guess you’ll know when its running and spray some carb cleaner near the throttle shafts and hear the idle change.
When I rebuilt mine, the holes were in perfect shape, the brass throttle shaft was 1/4 worn away, a new shaft and it was perfect like new. I had no need to bush the holes.
Davin and crew. Would you mind posting the name brand, model number, and the chemical you use of the ultra sonic cleaner? Also same info for the tumbler. Thanks.
I do have a cool project, but it's fighting me and I can feel myself getting frustrated. So, I step away and watch you until the willingness returns. Frustration leads to more problems.
Be cautious of using abrasive products like scotchbrite on your lathe. They shed abrasive particles that will over time grind down the ways of the lathe, causing it to turn a taper. Generally if you plan to use abrasives on a lathe you should cover the ways with newspaper or aluminium foil, and carefully clean them after you're done to remove any dust that may have snuck past the covers.
You just did the classic mistake, what you fitted was a service kit and not a rebuild kit. You need to look at the play in the throttle spindles and wear in the bodies. Engine will run poorly if this is not addressed. I rebuild lots of these in the uk if you need help give me a shout.
Replace the rocker shaft,and bushings!! Your not going to save time by reusing them. When you put the shaft in the lathe it showed a bend in the shaft. Save the hart burn get new ones.
![[TH] 2024 PMGC League | Survival Stage วันที่ 1 | PUBG MOBILE Global Championship](http://i.ytimg.com/vi/FVFT-PFwU80/mqdefault.jpg)
There was a guy in Michigan named John Twist at University Motors (now closed) in Grand Rapids who was a magician with British cars. He is retired but I believe he still gives seminars and workshops. The next time you have a British car and have questions he would be someone to call.
I've owned a couple of MGB's and at first those SU carburetors were intimidating but after watching John's TH-cam videos and some advice from the MG Experience forum I came to love them. I converted one car back from a modern Weber that a previous owner had installed back to SU's and it ran so much better.
SU carburetors are among the best. The Hagerty videos are very engaging, well done and informative. This one is no different. Great job.
A side note. Making a custom intake manifold for a Harley-Davidson MC from some aluminum tubing and plate that enables you to affix an SU to your Harley improves performance of your MC quite a bit. Getting it jetted correctly isn’t that hard and it’s worth the effort. I did this many years ago with a 1956 KHK I had. The SU carb and some other improvements I made to its breathing made that rascal run fast.
I LOVE SU carbs!
Such a great carb to drive and work with.
We ran our class built Datsun 1600 (510) on the Factory Hitachi SUs and loved them 👌
Never went out of tune for rally after rally with the Japanese linkage system.
G'day Hagerty Channel. I am not a professional mechanic as yourselves, but I have been working on Mini's for several decades. Regarding the rebuild of your SU carb's, I would advise you to do a couple of things. - You should do a balance check - to make sure the dashpots fall at the same rate. Now that you've replaced the jets, you might want to consider checking that the jet seats correctly. You may have done all of this off screen, but if not, I'd be happy to take you through this in detail if needed. Getting them balanced and set up correctly will make the tuning process much less painful. Thanks for the great channel. Very entertaining and informative. Cheers.
When Davin says "get out in the shop and get your work done", it actually makes me go and do it! Thanks, Davin!
same here
If you don't happen to have a lathe, chuck that rocker shaft (or whatever you might want rotating to polish/clean) into a drill and do it to it. I've done this on old bicycle axles where there was some pitting on the bearing race cones and it's a good shadetree way of "machining" a surface. Not the most precision way of doing things, but it works for old beaters.
Awesome tip!
The Chrysler slant 6 looks great with triple SUs, a popular mod in Oz. Much neater with triple cables rather than messy linkages
I like to watch all your engine assemblies no matter how boring they are to you
Great carb strip down but what would really help those of us that don’t have a reference carb is to show how that torsion spring fits for the choke.
Davin, really enjoy your videos, your varied language and kind ways! Would have enjoyed working with you if that ever would have happened!
I love the SU carburetor, it's so simple, self metering, easy to tune, and reliable. I've played with many types of carbs and I genuinely think the SU is the best to use. I particularly enjoy the simplicity of the fuel enrichment by pulling down the jet instead if having a choke.
This thing is gonna run better then it did when it came off the assembly line.
Greetings from the UK - cant wait to HEAR that Mini Cooper fire up - weel done as ever
Don't forget the throttle shaft bushings. They wear and leak air making achieving a good idle and balance impossible. There are sealed ball bearing kits available. Moss Motors has a good page on re-bushing the carb bodies.
Oh yeah, turn between centers...
I got a real cool project out there. Just waiting on my machine shop to get me my heads back! But being patient and paying him well as you say.
Those carbs really cleaned up.
".. my shaft is a bit longer than the basket..."
Mustie1 says; "There's a joke in there somewhere."
Hay David don't forget to stake the butter fly screws. Or some type of lock tight. I had one back out on me . Let say the valve didn't like it very much. That was a early learning experience for me.
My dream would be to hang out with you all and rebuild any car. I'd happily push a broom all day as long as I could absorb the knowledge. I could justify the tools if I had the knowledge, and I'd get the confidence to try more. Also happy you have teamed with Rock Auto. I am happy to give them money compared to A*******n.
Rock Auto uses all imported parts primarily.
Loving your Mini build , cant wait to see it fully assembled !
I like this channel.
My dad has an Austin Healey 3000 mk2. The carbs look the same. It's been being restored for some time. No end in sight.
My mom is from Detroit.
Way to go Davin. That is gonna be sweet !!!!
Vapour blasting is sooooooo satisfying!!!
I wish you guys would do more in-depth build videos. Time-lashes are great but it’s nice when you show everything.
Albeit I entirely agree, they probably don't have the time or resources to film for such things often. Not to mention TH-cams viewer retention, for videos that long, usually suffer greatly discouraging creators like Hagerty to produce long elusive content.
In my honest opinion most, if not all, of these quick videos show you more than enough to replicate the build process yourself. Chances are if you have this engine in front of you on a stand, you should probably already have done your research on it, which is just a few clicks away these days. From my perspective these videos best serve as a form of commemorating these engines and the legacy of each vehicle while also exposing those who aren't able to have the opportunity to see the innerworkings at such an in-depth level.
The wear on the rocker shaft will cause a decrease in oil pressure. Cheap insurance to just buy a new one. Good thing you did one carb at a time as you cannot mix and match parts when it comes to the piston and suction chambers.
Back in the day, I did a lot of those old A-Series engines and almost never had reusable rocker shaft or rocker bushings.The shafts were pretty poor material and wore out in the 80K miles those engines usually got before needing an upper end overhaul. Maybe that one was replaced at some point.
tHanks for posting Jim. I have loads of these parts that sat for decades. I can't tell what will be able to be saved and what won't. I keep thinking "keep the original" but recognize that may be foolish thinking. For now, I'm just moving crates of parts to better storage.
I concur 110% James.! Hagerty takes 20 minutes to assemble a 4-BBL carb, and 4 mins for our Furend parts.! Aggravating...
SU=Skinners Union, a very old English Company.
An SU is a very simple carburetor yet reliable and very efficient, they are almost as good as EFI with an SU carb you can NOT over carburate because they use engine the engine sucks in what it needs, mixture is set by adjusting the needle which controls the mixture.
An HIF6 SU ( SU, HIF= High Air Flow ) they can flow as much air/fuel as a side draught Weber for a lot less money!
This takes me back to my apprenticeship, my word.......
I gotta get me a vapour hone cabinet and a tumbler. I like shiny mini parts 😊👍
Really, really nice job on those carbs, Davin! I can just imagine what some dude, somewhere, is spending on shipping his SU's back to Jolly Ol' Britain to get redone! I always enjoy your episodes, but because I love Minis, and the engine is so unique for its day, this rebuild is especially fun. Kudos to everyone involved!
You also need to bolt the transfer case to the gearbox with the idler gear installed and check the idler gear thrust clearance.
Pro-tip: Instead of Lemi-shine, use bulk citric acid crystals. It's exactly the same thing at 1/10th of the cost.
You buy convenience with Lemi-Shine. You can't run out real quick to buy bulk citric acid at Walmart. But yes, you are totally correct on this. 👌
@@mannys9130 Amazon delivers it in 24 hours. You don't often have to "run out" for it when you have a 15 pound bag.
I had two SU carbs on a 1969 Volvo 122S. My biggest problem was the bushings on the throttle shaft - if these are worn you have problems with idle mixtures because the worn bushings / shaft form a vacuum leak. You need to a) get new bushings and throttle shafts, b) drive out the old bushings, c) drive in new bushings and most important d) ream those new bushings for an almost zero clearance on the new throttle shaft -the old snug but free business. There were no shaft seals on the old SU carbs I had. Lucky for me a local mechanic had the reamer, because the reamers were a scare commodity. FYI: We used ATF as damper fluid, and not brake fluid as some suggested at the time.
A wise owner will clean the dash pots ever fall so as to remove any moisture 'cause they can freeze in the winter time making for a no start condition. Likewise these parts must remain perfectly clean, no dust or dirt to disturb the air bearing area. When they work they are fantastically good carbs!
Been there done that. Though with three!
The carbs to use for all you desperados out there is the pre emission carbs with floating needles. You cannot buy a decent needle for the emission carbs for tuning. A heap of needles are/ were available for the non smog carbs.
IF set up properly they are near trouble free. Smooth idle though is sometimes an issue.
Until recently I had Holden 6s here with triple 45mm Webers and and still have another with triple 1 3/4 SUs. Both on racecars but were very reliable.
I loved my Buick 3.8L...warts and all. It is still a great motor!
Carburetors look new now. 😎👍🇨🇦
Waitin.. For the finale💪
I've Got a tea crate full of SU carbs in the shed.
the wear on the rocker shaft is visible on the video. a new shaft is ~20 bucks
Great skill mecanic rebuilt
Can’t wait for the next video!
Cold project maybe! It's only just above freezing!
I don’t understand the sped-up video segments. Who thinks we don’t want to sit and enjoy watching Davin disassemble and then reassemble each and every little detail of an SU carb?
"and now Ed for the weather report!"
Whilst in your case you had the opportunity of running the carbs before dis assembly, you should allways check the clearances of the throttle shaft and the body. They are the aquiles heel of the unit as the bronze shaft tends to wear away the aluminium casting on hogh mileage cars leading to rough idle due to air leaks. You can fix that either via oversize shafts or bushings which are relatively easy fixes. Again, in your case probably not a bid deal as the units looked to be in relatively good condition.
Presumably you changed the throttle screws (which are withworth threads!)
What solution do you use in the ultrasonic cleaner?
Keep wrenching! you are the reason I am suscribed to this channel.
Not done in a 4-minutes shoot...
Replacing the throttle shaft bushings on the SU's in my P1800S was essential to actually being able to adjust and balance the carbs.
@@bobbarron6969 EXACTLY.! Bob I agree, my Zenith 175CD's needed them BADLY.
Never saw a throttle shaft that didn’t act as a idle butterfly valve bypass :)
Looking fantastic!
Cool, never seen carbs like that before
Damn it I've been watching this from the start it's different
Another great episode! I Would love to see the dyno numbers of these full engine builds.
I hope you added some lock tight or other locking material to those throttle plate screws. Or staked them.
I was thinking the same thing, certainly don’t want the motor to swollen one
Great vid!! 👍👍👍
if pressure is an issue with the dishwasher soap then try the non-sudsing dishwasher machine soap.
I want this carburetor 😊
Those will work nice on a Datsun L16-18 motor.
Not 1 1/4, way too small. 1 1/2 for stock and 1 3/4 for a serious engine. Though a pair of 40 or42mm Webers are better
SUPERB!! 👍
I rebuild a lot of those in the past
Did you check the code on the needle that goes into the jet (against the replacement in the kit) as they are different for many applications, especially if the engine has been modified.
Agree on all the comments on the rocker bushes and rocker shaft. You loose a lot of valve lift if there is any wear in these parts...they are so cheap, its simpler to get new / uprated parts like roller rockers
What mesh media do you use for the vapor blast? For the tumbler, try Cascade dish washing detergent, it is non-foaming and non-spotting and you can use any concentration you want.
Not sure what size they are, but we use a glass bead media.
@@Hagerty The size should be on the drum you get it in. It will be marked as a screen size like 120-200 or a 2 didget number, 120-200 is size No. 11. The higher the number the finer the media just like sand paper
Cool car,I’m back to fixing the snowblower that won’t run ,thanks to the internet everything is possible
Then after you do the rockers you can do 300 cases of 308w.
What kind of fit was there on the throttle shafts to the carburetor bodies?
My buddy had a 59 TR3 with this same type of carburetors . The first set of carburetors the carburetor bodies the holes were wore out causing a bad vacuum leak. He had to find another set that were much better.
I'm dying to find a place to do vapor honing on my old bikes near me.
I'm in MI like I think y'all are, any suggestions?
Shoot I'll drive out to Hagerty and do the work myself
How about a minute or two of "here's how the side draft SU's function" when you install them or tune them. I rebuilt twin SU's on my TR-3 and never understood it then or now. I took it to someone to have them tuned and he said "who on earth tuned these last time?'" I just said it must have been the last owner...
How come I am hearing "come together" by the Beatles right now?
Am I too paranoid for marking the rocker arms and then putting them in the same place (as well as the rest assembly)? I was under the impression that parts that worked together for quite some time get unique wear pattern and if you mix them later on it accelerates the wear. Or is it not that crucial?
Is vapor honing suitable for cleaning carburetors? As I understand it, vapor honing is just media blasting with water. Couldn't some of the media get where it's not supposed to be and possibly cause a blockage?
didnt see you check for spindle wear? did you take the spindle out and mic it up? puting back a rocker shaft with wear ridges? is this another half arsed job like knurling valve guides?
I didn’t notice you putting oil in the carby dampers ?
Those SU Carburetors seem to be like motorcycle carburetors. @9:10... I think your cameraman likes it! 😜😜
I have an old advert with Devin featured as a parts runner If I send it with a return envelope would Devin sign it and send it back? I think it will class up the man cave.
Nice! I'd vapour blast everything of it had one haha
You know BMW K1 16 valve heads fit the BMC A Series with only a little moding
💪
Love watching this - Gotta ask -was there no slop in the throttle shafts ? Didn't see you check but am assuming you did before disassembly.
Never, ever fully grip a shaft rotating in the lathe. If that scotchbrite grips it will tear your arm off. Support it from underneath resting on your fingers and use kero or coolant to wash the debris away.
I dunno man, is a carb SU rebuild without rebushing the throttle shafts or at least replacing them really a rebuild? I guess you’ll know when its running and spray some carb cleaner near the throttle shafts and hear the idle change.
Depends on how much wear, but it's a decent thing to call out: These carbs had a reputation for getting wear.
When I rebuilt mine, the holes were in perfect shape, the brass throttle shaft was 1/4 worn away, a new shaft and it was perfect like new. I had no need to bush the holes.
Multi $1k lathe as parts cleaner, yeah practical home tip…. :)
Or take pictures while you're disassembling?
Davin and crew. Would you mind posting the name brand, model number, and the chemical you use of the ultra sonic cleaner?
Also same info for the tumbler.
Thanks.
With what spray dis he spray the metal parts after the vapor blasting?
The lathe has a live center for a reason. Use it.
Thought I was the only one thinking that!
Can you tell us the name of the band and the bluegrass music you play during this clip - particularly the piece at 4:10
What is he best home tool to use to tune a carb correct
I ❤ S U.
Snowballs 440 next? Please?
Love the channel but just fit a new rocker shaft as they're cheap
Does the vapor honing leave grit and if yes how do you get it all out?
2:37 - Davin, what are you spraying on those parts? Paint??
😎👍
where did the washers go?
I do have a cool project, but it's fighting me and I can feel myself getting frustrated. So, I step away and watch you until the willingness returns. Frustration leads to more problems.
what happened to the 37 coupe?
Anybody know if TSP work as well as Dawn?
When you guys gonna make progress in that dirt car 440 engine?
Soon, hopefully!
Those carburetors resemble motorcycle carburetors more than automotive carburetors.
Be cautious of using abrasive products like scotchbrite on your lathe. They shed abrasive particles that will over time grind down the ways of the lathe, causing it to turn a taper.
Generally if you plan to use abrasives on a lathe you should cover the ways with newspaper or aluminium foil, and carefully clean them after you're done to remove any dust that may have snuck past the covers.
You just did the classic mistake, what you fitted was a service kit and not a rebuild kit. You need to look at the play in the throttle spindles and wear in the bodies. Engine will run poorly if this is not addressed. I rebuild lots of these in the uk if you need help give me a shout.
Take a picture with your phone before you take it apart next time, even better reference also and SU carb repair manual.
You didn't show us what magnet you got...
Replace the rocker shaft,and bushings!! Your not going to save time by reusing them. When you put the shaft in the lathe it showed a bend in the shaft. Save the hart burn get new ones.
The rocker shaft is too badly worn to get consistent valve operation. Should be changed.