I grew up in Milan in the '60s and an Aermacchi 350 was my first real motorcycle. For regular servicing I took it to legendary tuner Osvaldo Coppelli and, around the corner from his shop, was the Aermacchi parts store, where I remember an elderly lady always dressed in a black smock who knew every single part number by heart. Behind the counter there were long shelves with every part down the last washer. One time I rode to the shop without wearing a helmet and Osvaldo dressed me down, "No helmet, no service!", he would say. Thanks for another great video that brought back great memories of my youth!
Hey David, I just found your comment! I liked your story, thanks. I still am a big fan of Aermacchis, and I'm taking mine down to the Salt Flats August 22 to see if I can set a record...
I raced 250cc and 350cc Aermacchis on short circuits and the TT until the two strokes took over. Watching you with your immaculate bike brings back happy memories. Best wishes.
This is all very familiar. I had an Aermacchi 350 racer when at university in the UK in the mid 1960's. I was using it as everyday transport as well as the occasional race. It was a pig to bump start. I spent hours fiddling with the Magneti Marelli points ignition system and the Dellorto (later Amal GP) carburettor. It never really ran properly until I had the whole bike rebuilt in the late 1970's by Dick Lintott at Crowborough. Sadly when our growing family dictated a larger house in 1983, it had to go.
Sorry to hear you had to part ways. My 350SS is very easy to bump start, which is good, because kickstarting is almost impossible. Aermacchis have their quirks. I only just found your comments, sorry it took 11 months...
I remember friends have the Harley 350 version of this in the late 60’s,early 70’s. A lot of guys were flat tracking them too. Nice to see someone restoring one.
Hello Paul, great to see you looking so well! I have to admit calling to the TV “ just fit the original one to try it out!” Velocity stack that is. It’s good fun to watch because it’s true to life, things just don’t go straight together. There is normally something to catch us all out. You will get to hear it roar for sure! Thank you all for the video. Regards Kevin.
Thanks Kevin. Only just found your comments after 11 months... I am even healthier now. And, taking the little Aermacchi down to Bonneville August 22. Hoping to set a Record....
I dont have a shop, I don’t know my way around an engine, I don’t even have a driving licence but I gotta tell you I throughly enjoy watching your content Paul. Looking healthier/younger every video
Hello Paul & Mitch (and Gary!). Thank you as always. Have you checked and set the float level? That's the very first thing to establish as a baseline setup for any new carb.
You know , we know , you will get there Paul , if anyone can . I remember an unexpected crowd of neighbors and friends gathering at my garage to see me fail at my bikes first start after new cams and pistons , total top end job . I had oiled everything rather well already so I left the plugs out to clear the excess oil and raise oil pressure when I hit the electric start . Two columns of oil , hollow of course , shot out of the spark plugs holes narrowingly missing my mates leathers and staining the wall for ever ! Yup , it started on the button too once I had the p[lugs in . What a grin moment ! Best luck next time ; could you not have machined in , or manually marked , degree lines on you moving timing plate ? A man of your skills could do that easily .... !
Good evening Mr. Brodie, Glad to see you in such good health. The bike is looking lovely and I'm really looking forward to hearing it run and see you riding it. Greetings from Germany
Beautiful work on the bike. Finding TDC with a piston stop is pretty easy: Bring the piston to the stop in one direction, mark the timing wheel, then rotate the crank in the opposite direction until the piston stops and mark the timing disc again. TDC is between the two marks. To make a stop, bust the insides out of a spark plug and braze a bolt into it. (I've always lusted for an Aermacchi street bike. I'd even take one of the fugly Harley ersatz versions.)
Thank you. Took me back 50 odd years... Used to race a 250 AlaVerde in production bike races. Could only do reasonable well in the rain. The Japanese bikes were way stronger, yet the AlaVerde handled a lot better... Those were the days!
We wanted to hear it run too, there should be a special place in hell for people who steal motorcycles, especially special ones like yours, I had a special bike stolen a year ago and I haven’t got over it yet. Thanks for the vid. Regards from across the pond.
Hello Paul, very nice bike. You must make some tubes for the bellmouth to conect with the holes. The holes must been in the bellmouth like in the original one
It looks as though you are playing around with an Amal Mk2.... If so you need to look at the choke circuit again. Block up the hole you just drilled again with a piece of electrical tape stuck to the carb body and then fit the velocity stack over the taped hole. Then take off the float bowl and block the choke jet or use some kind of blanking screw to replace the choke jet or even solder the jet hole up. Refit everything and set up the carb as is your requirements . EG #25 Pilot Jet .106 Needle Jet #3 Slide 2C3 Needle Air Jet 3.5 (I noticed your carb has this fitted, it is a loose fit and is situated between the velocity stack and the carb body. It shows on yours as a lighter coloured alloy ring. ) Idle Air screw 1.5 turns out As a starting point. THE ABOVE SETTINGS MAY NOT BE QUITE RIGHT FOR YOUR BIKE SO PLEASE CHECK. Bare in mind you now have no choke circuit so use your hand and some Ether (easy start). Note: Before you drilled the hole you had no air through the choke passages but if the choke jet was still active then the bike would flood or not fire very well. By drilling the hole this would be like putting the choke on but you need to have the tick over screw already set and not touch/move the throttle grip while starting the engine (this is how Amal designed the starting procedure using the choke). Also the other settings of the carb would now be over ridden which may have the effect of the bike not starting as you found..
Superb video Paul. The bike is stunning and represents your attention to detail perfectly. I'm in no doubt that you will iron out the snags. Best wishes, Dean.
Excellent episode as always. The honest alternative to those silly ‘Will It Start?’ videos. Certainly had me scratching my head. Only revving when you cover the velocity opening does sort of suggest weak mixture, which could mean the main jet is too small or blacked?? And Really Great to see you looking so well Paul. Hope you’re clear of problems completely now. Are you suing the government? Many are. You were lied to, as we all were of course. In your situation I would want to see that spawn of Castro indicted for crimes against humanity. Good luck with starting diagnosis. Looking forward to seeing this one running and on the track. Peace
I might be missing something, but my understanding is that Lucas Rita ignition should be set to 34 degrees advance at 6500 RPM. If the ignition is set to 34 deg static it'll be far to advanced to run properly.
Great video as always Paul, thank you for uploading! 👍👍 Don't worry that you couldn't get it running in this video, we know there's always some kind of gremlins to chase out when building a bike from scratch. 👌
When i was a younger lad I had to push a AJS 7R back to the pits at Pukekohe race track in New Zealand for the owner , it was a buzz . at the time if felt very light Compared to my DR 350 road bike .
I'd raise the slide needle a notch to richen it. If you can get it to idle you can check the slide cut away seeing how it pulls from idle. Put the tip of you finger in the cut away and open the throttle. If it revs more readily the slide is too lean, needs a smaller cut away. Runs worse, probably needs a larger cut away. It'll get you closer to getting your timing set. Once timing is right you may have to change the carb settings again. Good to see you back at it. 👍
Yes too many people ignore the slide cutaway and that can bite you big time, I used to modify the slide cutaway on Aprillia 125's because they were too lean on the slide making them hard to start. Many people just use the idle jet to achieve the same thing and when the slide cutaway is too rich instead of either buying an expensive slide or modifying the cutaway on their existing slide they go to a leaner Pilot Jet and that is when it can bite you big time, Roadracers and Flat track racers are running at high nengine rpm at the end of a straight and when you back off you are running on the Pilot Jet and if you tried a smaller Pilot Jet to cure start richness then the leanness that comes from too small a Pilot Jet can lead to seizure on the overrun in those scenarios.
@@paulbrodie There's another anomaly to check, and that is the exhaust system. I looked to see if you did a "build" video on it. And in this video I couldn't see if the megaphone had a reverse tip or was open. I've come across a few tuning issues directly affected to the exhaust system that are pretty simple to check. What you can do is, take a long 3/8" extension and put the biggest socket you can find on it. When you fire the bike up put the socket up the pipe. What this does is breaks up the reversion back thru the pipe. The reversion charge can flow right thru the combustion chamber during valve overlap and shut off the intake charge at the carburetor. Sometimes if you get spit back the socket will stop it. Spit back usually means lean mixture. But one Harley i worked on and I had black smoke rolling out the exhaust and the thing was spitting back almost every revolution. constantly spit back at idle. I had the richest low speed jet in it. Timing was correct. I took extensions with sockets, ran them up the pipe and the bike idled perfect. A Triumph 750 Bonneville had some kind of "replacement" carbs for the Concentrics (they're effin' crap) Bike had just the header pipes on. No amount of jetting, slides, and needle settings worked. In the end I took a couple of mirror clamping straps, bent them to bolt onto the frame and the other end bent to get into the path of the exhaust, and that disrupted the exhaust flow to stop reversion. I'm thinking I settled at about 1" behind the pipe. So, if everything seems to be set right, the exhaust can be the culprit.
Love it! and I am at exactly the same point as You, with My build ( Citroen 2CV based , Lomax Three wheeler) I have just finished fitting a tiny Supercharger, and I'm running but with carb problems. I do love tinkering and tuning though. I will try and put up a video for everybody when I can. Best of luck with it My friend. Best Wishes Dee
*_Take a pink pong ball and drill a hole all the through it and stick it in the bell. Those carbs need restriction to work properly, thats why its bogging down when you throttle it._*
Paul Brodie check out the whole carburetor do you need to level the floats and when you put your hand over the top of the carburetor does it work or not !!
what we did hear paul, sounded like a little monster is lurking within, just waiting to be unleashed,til next time thanks dynamic duo, and gary, the third man 😇👍
Nice to see you back on bike. The 'choke' plunger should be sealing the circuit, if your not running choke you didn't need the extra hole in bell-mouth. Did you fit the plunger with spring and then make blanking plug for top? (I forget what you showed on carb vid) As I'm not really familiar with modern AMAL, is there a seal on base of plunger? It's rare but on Mikuni's, (looks like AMAL copied them, bit ironic as Mikuni made AMAL under licence) if the seal is missing it allows fuel to flow through the 'tiny super rich carb' (which is what that type of enrichener circuit really is) Earlier Mikuni's had a closer fitting plunger plus a 'needle' to seal off enrichener so didn't use neoprene seal
Hi Paul, Great to see the Aermacchi running! You'll get the carburation sorted I'm confident🙂. Can you reveal detail how you connected the revcounter. Look forward to further videos👍 Thanks, Claus
Greetings from Finland. I have been following your channel for some time now and your work is fascinating. I am glad to see some real progression with your work. Both you and your bike look great! P.s. Finland’s country code is 358👍
After months of dicking around I finally got my '54 beetle running properly. Turns out the original carb just wouldn't work. Swapped it out for another one and now it is saweeeet! Good luck Paul let us know what you found. In the British car world we say that 90% of carb problems are ignition but sometimes it really is the carb. BTW why didn't you static time it? Was it not possible with the electronic ignition?
So when you hold your hand over the throat your choking it which causes it to pull more of a vacuum and then it get fuel and starts to take throttle. Maybe your float level is way off? It seems like it’s not pulling fuel from the bowl. Or the idle circuit is clogged in some way and when you cause the increase in vacuum (blocking the opening) you bypass the idle circuit and run off the main Either way I’m sure you’ll figure it out Mr. Brodie!
Wow so near to firing up. I am sure you will get it soon. Paul two engines on the shelf behind you what is the upright cylinder engine?? Nice to hear and see your getting better.
That big hole for the Cold start circuit probably being blanked off could result in not having atmospheric pressure to the float chamber possibly causing a high fuel level. Another possibility is the rather steep angle the Carburettor sits at could mean the fuel level is not where it needs to be for clean carburetion. I used to modify Aprillia 125 carb slides as they were too lean ex factory making the bike performance weak at low RPM and a 125 two stroke needs all the help it can get, But too many people fix low speed carburetion issues with just the Pilot jet and that can be very dangerous on Road racers and Flat Track bikes as all too often at the end of a straight at high RPM when you back off you are running on the Pilot Jet and if you leaned out the pilot circuit to fix starting or low speed performance issues that can cause a seizure on overrun just as you peel off into a corner the worst case scenario possible. Slides are expensive but you can machine the cutaway to some extent to experiment before you need to buy a new expensive slide to get the tuning correct. Better option than a seizure slides are whilst dear much cheaper than either a hospital Vist or Race Bike crash repair.
I was thinking that if the air intake for the cold start was blanked off, if it was also used for atmospheric pressure for the float chamber would cause issues. But I never really worked with the square bodied Amal, only worked with the Concentric. But if it is the source of atmospheric pressure that would result in a lean condition as that pressure would be missing to "push" the fuel thru the jets.
I know what you mean about opening a carb and hoping to find something obvious. I have a 90s ZX-7R that won’t rev. I opened the first carb and the main jet was sitting in the bowl. Same with every other carb. D’oh.
Is it something with your enrichener block off? I’m not familiar with that brand of carb but in Mikuni/Keihin carbs the “choke” (enrichener) provides extra fuel *and* air. So if you blocked off the fuel but not also the air bleed, it would be terribly lean at idle and that would explain having to block off the carb with your hand to get it to run. Just a thought.
You and the bike are looking really good, Paul- can't wait to hear it running well with that open megaphone! (what are the noise limits at the circuits you ride at? Here in UK they're really oppressive)
I wonder if you can help me find a single exhaust pipe for the Sprint? I have called Ron Lancaster and posted on a couple of Aermacchi/Sprint lists and cannot find a single exhaust for my road bike.
Hi Bryan. I sold all my bending equipment to Ron Lancaster and he was supposed to take over and start building header pipes.. And then he did nothing. I would have to look and see what I have. 250 or 350? Send me an email. fussyframebuilder@gmail.com
Hey Mr Brodie, so very nice to see you,,Your looking Great, I'm Hoping your health has gotten better,,very well then Thank you very much sir,,I do apricate your Channel..long time fan...
$10 Grand for the bike and an inestimable amount for your skill making it, certainly the best Aermacchi when it undoubtedly fires up. Remember building my first rally engine and battling for hours to start it eventually found the rotor arm on the bench 🤣
Don't feel bad Paul, this is the exact reason I never liked to work on gas engines.... They are not very easy to work on and they're like having a trophy girlfriend. They're impossible to figure out and even harder to work w/ on a daily basis..... 😂 I'm sure you will get it figured out sooner or later, but until then, thank you and good luck. 😁👍❤
Yer lucky ya had a square Amal. try that shit with a Lake and set the miniscus. If yer choke circuit is bleeding at high rpm, reduce yer main jet size cause ya need a choke to start cold. Or use an aerosol can of wd40 fer cold starts. Square Amals are VERY GOOD CARBS !!
I grew up in Milan in the '60s and an Aermacchi 350 was my first real motorcycle. For regular servicing I took it to legendary tuner Osvaldo Coppelli and, around the corner from his shop, was the Aermacchi parts store, where I remember an elderly lady always dressed in a black smock who knew every single part number by heart. Behind the counter there were long shelves with every part down the last washer. One time I rode to the shop without wearing a helmet and Osvaldo dressed me down, "No helmet, no service!", he would say.
Thanks for another great video that brought back great memories of my youth!
Hey David, I just found your comment! I liked your story, thanks. I still am a big fan of Aermacchis, and I'm taking mine down to the Salt Flats August 22 to see if I can set a record...
I raced 250cc and 350cc Aermacchis on short circuits and the TT until the two strokes took over. Watching you with your immaculate bike brings back happy memories.
Best wishes.
This is all very familiar. I had an Aermacchi 350 racer when at university in the UK in the mid 1960's. I was using it as everyday transport as well as the occasional race. It was a pig to bump start. I spent hours fiddling with the Magneti Marelli points ignition system and the Dellorto (later Amal GP) carburettor. It never really ran properly until I had the whole bike rebuilt in the late 1970's by Dick Lintott at Crowborough. Sadly when our growing family dictated a larger house in 1983, it had to go.
Sorry to hear you had to part ways. My 350SS is very easy to bump start, which is good, because kickstarting is almost impossible. Aermacchis have their quirks. I only just found your comments, sorry it took 11 months...
I remember friends have the Harley 350 version of this in the late 60’s,early 70’s. A lot of guys were flat tracking them too. Nice to see someone restoring one.
Known as the 'Sprint" 250/350 with a high revving engine!
Thanks, but I'm not doing a restoration... I made this bike from scratch.
Always exciting in Paul’s shop. Thanks for the brief look into how frustrating it feels when reaching back in time….. 👍👍😎👍👍
Great little morning coffee watch, thank you for sharing fellas. Can't wait to hear her sing
Good to have you back on my feed!
Me too! Thanks for watching :)
Back in the day 60,70s macckies where exotic machines in the paddocks then yamahas arrive and blew everyone away ,,happy days
Yes, that is exactly how it happened...
Hello Paul, great to see you looking so well!
I have to admit calling to the TV “ just fit the original one to try it out!” Velocity stack that is. It’s good fun to watch because it’s true to life, things just don’t go straight together. There is normally something to catch us all out. You will get to hear it roar for sure!
Thank you all for the video.
Regards Kevin.
Thanks Kevin. Only just found your comments after 11 months... I am even healthier now. And, taking the little Aermacchi down to Bonneville August 22. Hoping to set a Record....
Hello Paul, no worries, have a great day out take care and set a new record! Thanks Kevin.
I had a 250cc Aermacchi stolen from me 55 years ago, it still makes me mad when I think about it. I've enjoyed watching you work on your bike. 👍
I dont have a shop, I don’t know my way around an engine, I don’t even have a driving licence but I gotta tell you I throughly enjoy watching your content Paul.
Looking healthier/younger every video
Thank you very much. Only just found your comment! I am even healthier than I was 11 months ago..
@@paulbrodie I still watch every video Paul.
The speed in which you’ve recovered has been astounding to see
It ran, that's a win in my book. Well done , all of you.
Paul looking good. Keep up the good. And always think positive
Hello Paul & Mitch (and Gary!). Thank you as always. Have you checked and set the float level? That's the very first thing to establish as a baseline setup for any new carb.
You know , we know , you will get there Paul , if anyone can .
I remember an unexpected crowd of neighbors and friends gathering at my garage to see me fail at my bikes first start after new cams and pistons , total top end job . I had oiled everything rather well already so I left the plugs out to clear the excess oil and raise oil pressure when I hit the electric start . Two columns of oil , hollow of course , shot out of the spark plugs holes narrowingly missing my mates leathers and staining the wall for ever ! Yup , it started on the button too once I had the p[lugs in . What a grin moment ! Best luck next time ; could you not have machined in , or manually marked , degree lines on you moving timing plate ? A man of your skills could do that easily .... !
Highest quality aermacchi content out there
Yes a long time, love it!
Fabulous looking race bike . Loved watching you build it . Your are looking great Paul. Take care mate cheers from Australia 🇦🇺
Hi from Brasil Paul! love to see you again! Health and peace....
Good evening Mr. Brodie,
Glad to see you in such good health.
The bike is looking lovely and I'm really looking forward to hearing it run and see you riding it.
Greetings from Germany
Beautiful work on the bike. Finding TDC with a piston stop is pretty easy: Bring the piston to the stop in one direction, mark the timing wheel, then rotate the crank in the opposite direction until the piston stops and mark the timing disc again. TDC is between the two marks. To make a stop, bust the insides out of a spark plug and braze a bolt into it.
(I've always lusted for an Aermacchi street bike. I'd even take one of the fugly Harley ersatz versions.)
Thank you Paul for the education on diagnosing and setting the timing on a bike. I never fully understood how that worked before 👍
No worries! Thanks David :)
Too bad but you did warn me, that they are temperamental and the timing was tricky! Confident you'll get it happening in the next edition! Nice bike!
Can't wait to hear it roar!
My goodness how much I love your videos. Information, artistry and skill. Thank you! Go Paul, keep moving forward!
Agree 100%
Great video guys, great to see you are healing,
Thank you Johny. :)
Love it. ❤ keep picking away and get her on the next one
Paul: you are looking and sounding really well. !! 😎👍
Almost there Paul great to see you looking well & I will look forward to hearing it run next video.
Thank you. Took me back 50 odd years... Used to race a 250 AlaVerde in production bike races. Could only do reasonable well in the rain. The Japanese bikes were way stronger, yet the AlaVerde handled a lot better... Those were the days!
Thanks for sharing memories. Yes, those were special days; such excitement around motorcycles :)
Great to see you recovering well Paul👍
Hi Paul I'm sure you'll get it sorted an i look forward to hearing it when you do, see you in the next episode,
Great video Paul, can't wait for your next one so we can hear your fabulous bike sing 👍
We wanted to hear it run too, there should be a special place in hell for people who steal motorcycles, especially special ones like yours, I had a special bike stolen a year ago and I haven’t got over it yet. Thanks for the vid. Regards from across the pond.
Michael, just found your comments, thank you. I agree with you 100% regarding bike thieves....
Hello Paul, very nice bike. You must make some tubes for the bellmouth to conect with the holes. The holes must been in the bellmouth like in the original one
It was close ,,, but you will get there ,,, no point in rushing at it , Ill keep watching and you keep tweaking .
It looks as though you are playing around with an Amal Mk2.... If so you need to look at the choke circuit again. Block up the hole you just drilled again with a piece of electrical tape stuck to the carb body and then fit the velocity stack over the taped hole. Then take off the float bowl and block the choke jet or use some kind of blanking screw to replace the choke jet or even solder the jet hole up. Refit everything and set up the carb as is your requirements . EG
#25 Pilot Jet
.106 Needle Jet
#3 Slide
2C3 Needle
Air Jet 3.5 (I noticed your carb has this fitted, it is a loose fit and is situated between the velocity stack and the carb body. It shows on yours as a lighter coloured alloy ring. )
Idle Air screw 1.5 turns out As a starting point.
THE ABOVE SETTINGS MAY NOT BE QUITE RIGHT FOR YOUR BIKE SO PLEASE CHECK.
Bare in mind you now have no choke circuit so use your hand and some Ether (easy start).
Note: Before you drilled the hole you had no air through the choke passages but if the choke jet was still active then the bike would flood or not fire very well. By drilling the hole this would be like putting the choke on but you need to have the tick over screw already set and not touch/move the throttle grip while starting the engine (this is how Amal designed the starting procedure using the choke). Also the other settings of the carb would now be over ridden which may have the effect of the bike not starting as you found..
It was great to hear It run even if it wasn't perfect. Thanks for sharing 👍.
Superb video Paul. The bike is stunning and represents your attention to detail perfectly. I'm in no doubt that you will iron out the snags.
Best wishes, Dean.
Excellent episode as always. The honest alternative to those silly ‘Will It Start?’ videos. Certainly had me scratching my head. Only revving when you cover the velocity opening does sort of suggest weak mixture, which could mean the main jet is too small or blacked??
And Really Great to see you looking so well Paul. Hope you’re clear of problems completely now. Are you suing the government? Many are. You were lied to, as we all were of course. In your situation I would want to see that spawn of Castro indicted for crimes against humanity.
Good luck with starting diagnosis. Looking forward to seeing this one running and on the track.
Peace
Gary is a man of style and wears safety sandals 😂
I might be missing something, but my understanding is that Lucas Rita ignition should be set to 34 degrees advance at 6500 RPM. If the ignition is set to 34 deg static it'll be far to advanced to run properly.
Yes 34 or 35 is right. But you do need to start with static timing... we all have to start somewhere..
Hi Paul. Good to see you again. Looking good buddy
excellent video Paul! Thanks for sharing that!
And ... meant to say Paul .
Why not just try the original carb trumpet like thingy fitted to the carb as a test ?
That sound tickles my insides. Or as James May would say "Makes me feel fizzy".
Such a beautiful bike, also im glad to see doing well, speedy recovery 😁
Damn bikes...they can certainly be character building... Fingers crossed for the next start up attempt...🙂
Sounds very promising. I am sure it will Run next time. Pressing thumbs and send you greetings 👍
Great video as always Paul, thank you for uploading! 👍👍
Don't worry that you couldn't get it running in this video, we know there's always some kind of gremlins to chase out when building a bike from scratch. 👌
Looking good, Paul.
When i was a younger lad I had to push a AJS 7R back to the pits at Pukekohe race track in New Zealand
for the owner , it was a buzz . at the time if felt very light Compared to my DR 350 road bike .
man i love this era of machines, so cool looking and just mechanical.
I'd raise the slide needle a notch to richen it. If you can get it to idle you can check the slide cut away seeing how it pulls from idle. Put the tip of you finger in the cut away and open the throttle. If it revs more readily the slide is too lean, needs a smaller cut away. Runs worse, probably needs a larger cut away. It'll get you closer to getting your timing set. Once timing is right you may have to change the carb settings again. Good to see you back at it. 👍
Yes too many people ignore the slide cutaway and that can bite you big time, I used to modify the slide cutaway on Aprillia 125's because they were too lean on the slide making them hard to start.
Many people just use the idle jet to achieve the same thing and when the slide cutaway is too rich instead of either buying an expensive slide or modifying the cutaway on their existing slide they go to a leaner Pilot Jet and that is when it can bite you big time, Roadracers and Flat track racers are running at high nengine rpm at the end of a straight and when you back off you are running on the Pilot Jet and if you tried a smaller Pilot Jet to cure start richness then the leanness that comes from too small a Pilot Jet can lead to seizure on the overrun in those scenarios.
Thanks for commenting! :)
@@paulbrodie There's another anomaly to check, and that is the exhaust system. I looked to see if you did a "build" video on it. And in this video I couldn't see if the megaphone had a reverse tip or was open. I've come across a few tuning issues directly affected to the exhaust system that are pretty simple to check. What you can do is, take a long 3/8" extension and put the biggest socket you can find on it. When you fire the bike up put the socket up the pipe. What this does is breaks up the reversion back thru the pipe. The reversion charge can flow right thru the combustion chamber during valve overlap and shut off the intake charge at the carburetor. Sometimes if you get spit back the socket will stop it. Spit back usually means lean mixture. But one Harley i worked on and I had black smoke rolling out the exhaust and the thing was spitting back almost every revolution. constantly spit back at idle. I had the richest low speed jet in it. Timing was correct. I took extensions with sockets, ran them up the pipe and the bike idled perfect. A Triumph 750 Bonneville had some kind of "replacement" carbs for the Concentrics (they're effin' crap) Bike had just the header pipes on. No amount of jetting, slides, and needle settings worked. In the end I took a couple of mirror clamping straps, bent them to bolt onto the frame and the other end bent to get into the path of the exhaust, and that disrupted the exhaust flow to stop reversion. I'm thinking I settled at about 1" behind the pipe. So, if everything seems to be set right, the exhaust can be the culprit.
Keep up the good work Paul.
nothing sounds nicer than a single with a mega.
Love it! and I am at exactly the same point as You, with My build ( Citroen 2CV based , Lomax Three wheeler) I have just finished fitting a tiny Supercharger, and I'm running but with carb problems. I do love tinkering and tuning though. I will try and put up a video for everybody when I can. Best of luck with it My friend. Best Wishes Dee
Great job Paul and nice bike 😁😁👍👍
Im still really excited for you thar it runs! Great job guys!
*_Take a pink pong ball and drill a hole all the through it and stick it in the bell. Those carbs need restriction to work properly, thats why its bogging down when you throttle it._*
Paul Brodie check out the whole carburetor do you need to level the floats and when you put your hand over the top of the carburetor does it work or not !!
what we did hear paul, sounded like a little monster is
lurking within, just waiting to be unleashed,til next time
thanks dynamic duo, and gary, the third man 😇👍
Nice to see you back on bike.
The 'choke' plunger should be sealing the circuit, if your not running choke you didn't need the extra hole in bell-mouth.
Did you fit the plunger with spring and then make blanking plug for top? (I forget what you showed on carb vid)
As I'm not really familiar with modern AMAL, is there a seal on base of plunger?
It's rare but on Mikuni's, (looks like AMAL copied them, bit ironic as Mikuni made AMAL under licence) if the seal is missing it allows fuel to flow through the 'tiny super rich carb' (which is what that type of enrichener circuit really is)
Earlier Mikuni's had a closer fitting plunger plus a 'needle' to seal off enrichener so didn't use neoprene seal
Hi Paul,
Great to see the Aermacchi running! You'll get the carburation sorted I'm confident🙂. Can you reveal detail how you connected the revcounter. Look forward to further videos👍
Thanks,
Claus
Can't get any better than this. Two old guys discussing why the bike don't run right
Thanks!!!!!
Greetings from Finland. I have been following your channel for some time now and your work is fascinating. I am glad to see some real progression with your work. Both you and your bike look great! P.s. Finland’s country code is 358👍
After months of dicking around I finally got my '54 beetle running properly. Turns out the original carb just wouldn't work. Swapped it out for another one and now it is saweeeet! Good luck Paul let us know what you found. In the British car world we say that 90% of carb problems are ignition but sometimes it really is the carb. BTW why didn't you static time it? Was it not possible with the electronic ignition?
If anyone can, Paul can.
So when you hold your hand over the throat your choking it which causes it to pull more of a vacuum and then it get fuel and starts to take throttle.
Maybe your float level is way off? It seems like it’s not pulling fuel from the bowl.
Or the idle circuit is clogged in some way and when you cause the increase in vacuum (blocking the opening) you bypass the idle circuit and run off the main
Either way I’m sure you’ll figure it out Mr. Brodie!
👍Get that sucker running Paul
you are looking better.
It's Alive 🎉 🙏
Well, almost, but we did figure it out for episode 2 :)
Wow so near to firing up. I am sure you will get it soon. Paul two engines on the shelf behind you what is the upright cylinder engine?? Nice to hear and see your getting better.
That big hole for the Cold start circuit probably being blanked off could result in not having atmospheric pressure to the float chamber possibly causing a high fuel level.
Another possibility is the rather steep angle the Carburettor sits at could mean the fuel level is not where it needs to be for clean carburetion.
I used to modify Aprillia 125 carb slides as they were too lean ex factory making the bike performance weak at low RPM and a 125 two stroke needs all the help it can get, But too many people fix low speed carburetion issues with just the Pilot jet and that can be very dangerous on Road racers and Flat Track bikes as all too often at the end of a straight at high RPM when you back off you are running on the Pilot Jet and if you leaned out the pilot circuit to fix starting or low speed performance issues that can cause a seizure on overrun just as you peel off into a corner the worst case scenario possible.
Slides are expensive but you can machine the cutaway to some extent to experiment before you need to buy a new expensive slide to get the tuning correct.
Better option than a seizure slides are whilst dear much cheaper than either a hospital Vist or Race Bike crash repair.
I was thinking that if the air intake for the cold start was blanked off, if it was also used for atmospheric pressure for the float chamber would cause issues. But I never really worked with the square bodied Amal, only worked with the Concentric. But if it is the source of atmospheric pressure that would result in a lean condition as that pressure would be missing to "push" the fuel thru the jets.
Good to see Gary wearing his Japanese safety boots (that’s an Australian joke Paul)
I know what you mean about opening a carb and hoping to find something obvious. I have a 90s ZX-7R that won’t rev. I opened the first carb and the main jet was sitting in the bowl. Same with every other carb. D’oh.
Good story, thanks..
Is it something with your enrichener block off? I’m not familiar with that brand of carb but in Mikuni/Keihin carbs the “choke” (enrichener) provides extra fuel *and* air. So if you blocked off the fuel but not also the air bleed, it would be terribly lean at idle and that would explain having to block off the carb with your hand to get it to run. Just a thought.
You and the bike are looking really good, Paul- can't wait to hear it running well with that open megaphone! (what are the noise limits at the circuits you ride at? Here in UK they're really oppressive)
I wonder if you can help me find a single exhaust pipe for the Sprint? I have called Ron Lancaster and posted on a couple of Aermacchi/Sprint lists and cannot find a single exhaust for my road bike.
Hi Bryan. I sold all my bending equipment to Ron Lancaster and he was supposed to take over and start building header pipes.. And then he did nothing. I would have to look and see what I have. 250 or 350? Send me an email. fussyframebuilder@gmail.com
“We’ve been dicking around for too long” 😂😂 that sounds exactly like what my dad would say
Is he British too?
@@paulbrodie hahaha no sir. I’m not sure where he picked it up but my brother and I both say it all the time now.
Waiting for the next installment..
Gary in charge of the battery hold-down?
I guess so.
The color of the frame is nice. Is it RAL 7025?
It is grey from Home Depot. They sell a lot of it, can't think of the brand right now...
It looks like a color for machine tools.
👍👍😁😁
if that ignition plate is 4 inches diameter each 1/32 is one degree.
♥
Thanks Matthew!
Tremendous bikes, so Italian. Gary does not sound like he is from Seattle, sounds more like North England to me!
Leeds, York and Hull
You know you jinxed yourself by saying this was the first start and you didn't cheat. 😊
Hello Paul, Argentina
Hey Mr Brodie, so very nice to see you,,Your looking Great, I'm Hoping your health has gotten better,,very well then Thank you very much sir,,I do apricate your Channel..long time fan...
I think there is some problem with jets,needle or gasoline inlet
$10 Grand for the bike and an inestimable amount for your skill making it, certainly the best Aermacchi when it undoubtedly fires up. Remember building my first rally engine and battling for hours to start it eventually found the rotor arm on the bench 🤣
Can’t wait to hear it running in anger!
Don't feel bad Paul, this is the exact reason I never liked to work on gas engines.... They are not very easy to work on and they're like having a trophy girlfriend. They're impossible to figure out and even harder to work w/ on a daily basis..... 😂 I'm sure you will get it figured out sooner or later, but until then, thank you and good luck. 😁👍❤
Wait... no Mitch? 🤔🤷♂️🤣
Don't worry, Mitch is always behind the cameras!
@@paulbrodie Yeah, at least he wasn't yelling and screaming. :)
Ooops! Looks like you just killed a carb, beyond all possible resuscitation!
"Been dickin' around too long" should be your next video Paul :)
It's Murphys law, if Murphy isn't getting It's his wife. You'll get her dialed, don't worry. Just hearing it fire and struggle is a good sign.
Thanks, we did get it mostly figured out..
@@paulbrodie cool, I figured you would. I'll be watching the next video.
oops! in the end the carburettor gave you a lot of work 😒
Yer lucky ya had a square Amal. try that shit with a Lake and set the miniscus. If yer choke circuit is bleeding at high rpm, reduce yer main jet size cause ya need a choke to start cold. Or use an aerosol can of wd40 fer cold starts. Square Amals are VERY GOOD CARBS !!
Rev it up Paul