Robert, you twisted the base of the camshaft and valves without mounting the head onto the cylinder. You changed the type of gasket. You should check that the axis of the camshaft is parallel to the axis of the crankshaft. If not, you need to adjust the base with spacers. If you do not do this, the camshaft drive bushings will wear out quickly.
Thanks, Mirek. I appreciate the note. I did check and adjust the shimming for the camshaft body. I just didn't show it on camera. I started at 0.4mm, took alignment measurements per the manual, and adjusted the shims. I ended up with 0.35mm shims instead of the 0.4mm that were specified in the manual. I made some custom shims using stainless shim stock.
@@RobertAdairWorkshop hello again. I wrote to you about it because I made such a mistake myself. This was when the internet was not available to me. It is very easy to exchange experiences now, so I thought my remark would be helpful. You are a more experienced passionate than I was 30 years ago when you took that into account. I can only admire your work. My NSU Specjal Max is from 1954. Painting is waiting to be refreshed because I did it a long time ago.
NSU war damals eigentlich allen Herstellern in Deutschland technisch innovativ weit überlegen. Mit dem Mut für neue Ideen und der Begeisterung, auch bei den Serienmaschinen. Und dabei absolut alltagstauglich, für jedermann...Aber immer Tradition gewesen bei dieser Firma. Einzige Ausnahme: BMW 500 RS Rennmaschine mit 2 Königswellen und zwei obenliegenden Nockenwellen pro Zylinder! Das hätte auch von NSU sein können. Eigentlich hat Honda die Firmengeschichte später von NSU übernommen, weiterentwickelt und in die Gegenwart gerettet. Auch bei Honda erkennt man in den 70ern die gleiche Begeisterung für Technik und Innovation und Qualität: Eine 400 Vierzylindermaschine Viertakt Maschine , obenliegende Nockenwelle, für junge Leute ohne Technikverständnis? Und das funktioniert? Und bezahlbar? In Deutschland, 50er Jahre , nicht zu denken, außer der Max. Die CB 400 Four ist vergleichbar mit der Max: Technisch aufwändig, bezahlbar, absolut zuverlässig und läuft immer.
@@jensnitsche4994 Ich hatte eine 250 Max, eine schöne Maschine, und wünschte, ich hätte sie noch. Ich denke, wir haben einen ähnlichen Fahrradgeschmack..
Nice start ! I’m looking forward to see it finished. I have for a while come to the conclusion that the NSU was one of the nicest looking bikes ever made !
I hope you did open the crankcase. crankshaft main bearing is one of the things that has to be replaced during restoration! Every time I do one of those engines I follow the workshop manual and notes. This Engine looks like a simple design but a lot of changes were made to the lubrication and breathing systems during the short production time and non of those parts ar interexchangable. I hope everything went right and I hope you can enjoy the mighty 18bhp engine.
I didn't mention it in the video. It's in the longer movie. I found a cracked cylinder head with broken mount and was able to use the valves, springs, rockers and cams from it. I bought the remaining parts for the eccentric cam drive from NSU Hammel, nsu-hammel.de or on eBay.de. Total spent on engine parts was $2350.78 USD.
Hello Robert, excellent video, a clean and tidy job. I don't know much about mechanics and I didn't have a father who taught me that kind of thing, but with your video I can say that I learned many things that I didn't know and I'm very grateful. I am a happy owner of a '57 NSU Super Max, it looks very similar to the one in your video. What I would not give to have someone with his knowledge in my country to be able to restore mine. May you be very well, and do not stop your excellent work will bring you rewards at the right time. New subscriber
You must have found replacement parts for the cam and rocker arms. Surprising that it's possible for such an old bike! Or did you build them up and regrind them? Anyway, you did a beautiful job and I bet it runs great!
Thanks Victor. I didn't mention it in the video. Probably should have. I lucked upon a cylinder head with a broken mount but that had good valves, springs, rockers and cam. I did still have to get the drive rod parts (eccentric, cam bolt/hardware and counterweight) from Germany, used. Parts sourcing was quite a challenge on this one.
I actually have one of those engines that was intended to be installed in a Micro Midget from the 1950's. Those engines have the most fascinating valvetrain I've ever seen. How rare are those engines in the US?
Questions and Observations: I never saw any lock washers, Bend-Tab washers, or Blue Locktite on ANY of the critical nuts and fasteners? (cam nuts, Crank nut, Clutch hub nuts etc) it's a SINGLE, they vibrate like crazy, your asking for trouble. The "5mm Space on the spring bolts" thing might be a misprint (as old Motorcycle manuals often have) or some sort of bad translation from German to English OR maybe you misunderstood what they mean, Those bolts should be VERY VERY tight on the springs as they will come loose within 3 minutes of running if they are not and destroy the motor, as the clutch wears that space would increase that you measured, maybe the spec was referring to if it's 5mm or greater the clutch fiber plates are worn out? ALSO: you showed the destroyed rocker, and cam lobe, but never mentioned if you had them built-up with weld and refaced, or bought new components? And how did you verify the oil pump was working and oil was getting to the exhaust lobe of the cam? Even tho you thought the bottom end looked fine, did you remove and check the sludge plug in the crank weight? I'd bet it's PACKED full of junk as every antique Single cyl motorcycle engine I've rebuilt (many hundreds over the past 45+ years) Maybe not as bad since your NSU has a dry clutch, but still also something I wouldnt skip That type of Rod & Ball Clutch actuation down the center of the clutch shaft is very common amongst old bikes, Ducati used it on all their singles and Some of their Twins from the 1950's to the present day -
I didn't show things like using loctite blue or lock washers, but I did. Spring washers on the inside of the case. Lock washers on the top end to retain the cam body Just like NSU did. Blue Loctite on all of the other fastners. This isn't my first motorcycle. The 5mm space is not loose space and its not a translation error. It is such that the spring is compressed until the nut sits 5mm outward from the clutch plate when using new springs. I'm not sure of the spring freelength but I could get that if you're really curious. I'd estimate the springs are at least 60% compressed at that spec. They are firmly in place.. I did clean out the bottom end including the sludge traps. This is documented over on a thread I'm running on advrider but not included in the video. I replaced the top-end with another from a parts engine I found shortly after purchasing the bike. I didn't show it in the video, mostly, because I forgot to include it. There are hundreds of clips in that video. It's easy to forget something.
Sir! Subscribed !!! Thank you so much for your beautiful video about this unique engine. I am so grateful for the opportunity to see the unique valve return spring setup. I have seen only concentric setup so far. Sir! I was at the NSU museum and asked the staff about this conrod cam drive with my rudimentary German. They were unable to answer. Forgive my ignorance, but I hope you can help me understand why is there a need for 2 con rods? If the inlet and exhaust valves are keyed they could be on a single cam shaft ( no variable valve timing) . If this is the case, just one con rod should be enough to drive the cam shaft and both the valves. I think there are two conrods. If time permits please describe the oil flow path as well . I want to know how the oil reaches the rocker bearings. I assume it goes to the rocker after being scavenged from the crank case. I would be truly grateful for your help in educating me.
The engine head (with all parts) is completely lubricated by a narrow channel that goes directly from the oil pump. The oil goes (through channel ) from the oil pump through the engine housing , cylinder , engine head , rocker arm bridge and enters the camshaft (enters the hoel of the camshaft through which it passes main bolt that connect all parts ) . That bolt is specific ( the missing bolt ) it also has chanel for oil flow , and through that chanel because of pump presure , oil lubricate all bearings on camshaft . And because that bolt connect eccentric for camshaft drive, it also lubricant all that section with several chanel (cca 1 millimeter in diameter) . It is quite complicated lubrication .
There must be two cam drive con rods to prevent the cam from locking when only one con rod is at the top or the bottom... similar to the two driving rods on a steam powered train engine.
Nice work, the damages on the vent drive where surprising me but I have little information about problems concerning this type of engine. I wouldn't call the Max a rare Motorcycle, the Max was one of the most produced motorcycles from NSU and NSU was maybe the biggest motorcycle manufacturer in the mid 1950 with nearly 300k motorcycles sold in1955. In contrast to BMW they concentrated on small sized motorcycles below 500cc. When customers demand for motorcycles declined they switched to the production of small cars. Later they where known as the company producing the first Wankel driven car, something that may have broke their neck, they where bought by Audi and are now a part of the Volkswagen Group.
I didn't think I needed to specify, but rare here in the United States. I know they made 83k of them between 1952 and 1956 but most of those 83k weren't US export bikes. We only got them starting mid '53 and most that came here are long gone. You don't see them at vintage motorcycle shows. Anyway, rare here in the US. Probably much more common in Europe.
Hi, Russell. I bought some universal kits from Venhill. Two of their clutch kits and three of their throttle kits. The decomp cable and housing are the same size as the throttle cable. I made the cables myself. It’s pretty easy but requires soldering the ends on.
I forgot the speedometer cable. I got that one on eBay from a seller in Spain. the drive side end wasn’t correct and required me to fabricate a bushing. I can send you a cad model of the bushing if you have the means to make one.
Tha ks for getting back to me, most appreciated. I have seen some cable kits advertised but worried they may not fit and they are nit cheap. But I will give them ago with the knowledge I may have to adjust them. Thanks again Rusty
Yeah, that threw me off, too. When I had the swingarm out, the lever arm for the cantilever spring was there but had been cut off with an acetylene torch. We did a lot of research and it seems this bike was modified by an NSU dealership to fit the dual seat. As part of that, they cut the cantilever arm and retrofitted the rear shocks. You can tell they are retrofitted based on the shape of the shock perch, where it attaches to the monocoque, and the ribbed bracket that supports them on the underside of the rear fender section. The dead giveway to it being an earlier bike is in brake hubs and wheels. This bike has the smaller drums with the single leading shoe. It took a look of research on it and talking with some experts overseas to determine it was a modified 1953 and not an older model.
Correct me if I'm wrong... didn't you split the cases to check the transmission, main bearings, shaft end play? |n this video anyway it looks like you just painted the cases without taking the whole engine apart, which isn't a rebuild.
I've never had good luck with impact drivers, at least, not the ones you smack with a hammer. They always distort the head which is what I was really trying to avoid here. You're right about the valves. They and thier seats were in good shape and a quick lapping is all they needed.
This is interesting. My machine is a Max 250 powered Italian Caproni. from 1954.
Robert, you twisted the base of the camshaft and valves without mounting the head onto the cylinder. You changed the type of gasket. You should check that the axis of the camshaft is parallel to the axis of the crankshaft. If not, you need to adjust the base with spacers. If you do not do this, the camshaft drive bushings will wear out quickly.
Thanks, Mirek. I appreciate the note. I did check and adjust the shimming for the camshaft body. I just didn't show it on camera. I started at 0.4mm, took alignment measurements per the manual, and adjusted the shims. I ended up with 0.35mm shims instead of the 0.4mm that were specified in the manual. I made some custom shims using stainless shim stock.
@@RobertAdairWorkshop hello again. I wrote to you about it because I made such a mistake myself. This was when the internet was not available to me. It is very easy to exchange experiences now, so I thought my remark would be helpful. You are a more experienced passionate than I was 30 years ago when you took that into account. I can only admire your work. My NSU Specjal Max is from 1954. Painting is waiting to be refreshed because I did it a long time ago.
Thats the weirdest valve train I've ever seen! Very cool!
The NSU World Championship twin cylinder Races were engineering jewels and the basis of Honda's early race bikes
NSU war damals eigentlich allen Herstellern in Deutschland technisch innovativ weit überlegen. Mit dem Mut für neue Ideen und der Begeisterung, auch bei den Serienmaschinen. Und dabei absolut alltagstauglich, für jedermann...Aber immer Tradition gewesen bei dieser Firma.
Einzige Ausnahme: BMW 500 RS Rennmaschine mit 2 Königswellen und zwei obenliegenden Nockenwellen pro Zylinder! Das hätte auch von NSU sein können.
Eigentlich hat Honda die Firmengeschichte später von NSU übernommen, weiterentwickelt und in die Gegenwart gerettet.
Auch bei Honda erkennt man in den 70ern die gleiche Begeisterung für Technik und Innovation und Qualität: Eine 400 Vierzylindermaschine Viertakt Maschine , obenliegende Nockenwelle, für junge Leute ohne Technikverständnis? Und das funktioniert? Und bezahlbar?
In Deutschland, 50er Jahre , nicht zu denken, außer der Max.
Die CB 400 Four ist vergleichbar mit der Max: Technisch aufwändig, bezahlbar, absolut zuverlässig und läuft immer.
@@jensnitsche4994 Ich hatte eine 250 Max, eine schöne Maschine, und wünschte, ich hätte sie noch. Ich denke, wir haben einen ähnlichen Fahrradgeschmack..
Nice start ! I’m looking forward to see it finished. I have for a while come to the conclusion that the NSU was one of the nicest looking bikes ever made !
Eines der Interessantesten!
I hope you did open the crankcase. crankshaft main bearing is one of the things that has to be replaced during restoration! Every time I do one of those engines I follow the workshop manual and notes. This Engine looks like a simple design but a lot of changes were made to the lubrication and breathing systems during the short production time and non of those parts ar interexchangable. I hope everything went right and I hope you can enjoy the mighty 18bhp engine.
I will watch every episode! Would have enjoyed more info on the top end rebuild...sources, cost, how you dealt with the cam lobes and rocker arm etc.
I didn't mention it in the video. It's in the longer movie. I found a cracked cylinder head with broken mount and was able to use the valves, springs, rockers and cams from it. I bought the remaining parts for the eccentric cam drive from NSU Hammel, nsu-hammel.de or on eBay.de. Total spent on engine parts was $2350.78 USD.
Very cool. I like the detailed breakdown by component
Thanks!
great job!!😀
Hello Robert, excellent video, a clean and tidy job. I don't know much about mechanics and I didn't have a father who taught me that kind of thing, but with your video I can say that I learned many things that I didn't know and I'm very grateful. I am a happy owner of a '57 NSU Super Max, it looks very similar to the one in your video. What I would not give to have someone with his knowledge in my country to be able to restore mine. May you be very well, and do not stop your excellent work will bring you rewards at the right time. New subscriber
That's very kind of you to say. Thank you.
Excellent job.👍
Thanks 👍
You must have found replacement parts for the cam and rocker arms. Surprising that it's possible for such an old bike! Or did you build them up and regrind them? Anyway, you did a beautiful job and I bet it runs great!
That was my question as well.
Thanks Victor. I didn't mention it in the video. Probably should have. I lucked upon a cylinder head with a broken mount but that had good valves, springs, rockers and cam. I did still have to get the drive rod parts (eccentric, cam bolt/hardware and counterweight) from Germany, used. Parts sourcing was quite a challenge on this one.
I actually have one of those engines that was intended to be installed in a Micro Midget from the 1950's. Those engines have the most fascinating valvetrain I've ever seen.
How rare are those engines in the US?
Questions and Observations: I never saw any lock washers, Bend-Tab washers, or Blue Locktite on ANY of the critical nuts and fasteners? (cam nuts, Crank nut, Clutch hub nuts etc) it's a SINGLE, they vibrate like crazy, your asking for trouble.
The "5mm Space on the spring bolts" thing might be a misprint (as old Motorcycle manuals often have) or some sort of bad translation from German to English OR maybe you misunderstood what they mean, Those bolts should be VERY VERY tight on the springs as they will come loose within 3 minutes of running if they are not and destroy the motor, as the clutch wears that space would increase that you measured, maybe the spec was referring to if it's 5mm or greater the clutch fiber plates are worn out?
ALSO: you showed the destroyed rocker, and cam lobe, but never mentioned if you had them built-up with weld and refaced, or bought new components? And how did you verify the oil pump was working and oil was getting to the exhaust lobe of the cam?
Even tho you thought the bottom end looked fine, did you remove and check the sludge plug in the crank weight? I'd bet it's PACKED full of junk as every antique Single cyl motorcycle engine I've rebuilt (many hundreds over the past 45+ years) Maybe not as bad since your NSU has a dry clutch, but still also something I wouldnt skip
That type of Rod & Ball Clutch actuation down the center of the clutch shaft is very common amongst old bikes, Ducati used it on all their singles and Some of their Twins from the 1950's to the present day -
I didn't show things like using loctite blue or lock washers, but I did. Spring washers on the inside of the case. Lock washers on the top end to retain the cam body Just like NSU did. Blue Loctite on all of the other fastners. This isn't my first motorcycle.
The 5mm space is not loose space and its not a translation error. It is such that the spring is compressed until the nut sits 5mm outward from the clutch plate when using new springs. I'm not sure of the spring freelength but I could get that if you're really curious. I'd estimate the springs are at least 60% compressed at that spec. They are firmly in place..
I did clean out the bottom end including the sludge traps. This is documented over on a thread I'm running on advrider but not included in the video.
I replaced the top-end with another from a parts engine I found shortly after purchasing the bike. I didn't show it in the video, mostly, because I forgot to include it. There are hundreds of clips in that video. It's easy to forget something.
@@RobertAdairWorkshop Sorry, I was just commenting on what was shown (or not shown) Didnt mean to ruffle your feathers kid, looks good
Sir! Subscribed !!! Thank you so much for your beautiful video about this unique engine. I am so grateful for the opportunity to see the unique valve return spring setup. I have seen only concentric setup so far. Sir! I was at the NSU museum and asked the staff about this conrod cam drive with my rudimentary German. They were unable to answer. Forgive my ignorance, but I hope you can help me understand why is there a need for 2 con rods? If the inlet and exhaust valves are keyed they could be on a single cam shaft ( no variable valve timing) . If this is the case, just one con rod should be enough to drive the cam shaft and both the valves. I think there are two conrods. If time permits please describe the oil flow path as well . I want to know how the oil reaches the rocker bearings. I assume it goes to the rocker after being scavenged from the crank case. I would be truly grateful for your help in educating me.
The engine head (with all parts) is completely lubricated by a narrow channel that goes directly from the oil pump. The oil goes (through channel ) from the oil pump through the engine housing , cylinder , engine head , rocker arm bridge and enters the camshaft (enters the hoel of the camshaft through which it passes main bolt that connect all parts ) . That bolt is specific ( the missing bolt ) it also has chanel for oil flow , and through that chanel because of pump presure , oil lubricate all bearings on camshaft . And because that bolt connect eccentric for camshaft drive, it also lubricant all that section with several chanel (cca 1 millimeter in diameter) . It is quite complicated lubrication .
@@oldtimer-Z Sir Thank you for your kind reply. I was at the NSU MUSEUM at neckarsulm but there was no one there to explain.
What beautiful and unique engineering
There must be two cam drive con rods to prevent the cam from locking when only one con rod is at the top or the bottom... similar to the two driving rods on a steam powered train engine.
@@rrnsss Ralph Plagmann is the guy there
Neat motor.
Nice work, the damages on the vent drive where surprising me but I have little information about problems concerning this type of engine.
I wouldn't call the Max a rare Motorcycle, the Max was one of the most produced motorcycles from NSU and NSU was maybe the biggest motorcycle manufacturer in the mid 1950 with nearly 300k motorcycles sold in1955. In contrast to BMW they concentrated on small sized motorcycles below 500cc. When customers demand for motorcycles declined they switched to the production of small cars. Later they where known as the company producing the first Wankel driven car, something that may have broke their neck, they where bought by Audi and are now a part of the Volkswagen Group.
I didn't think I needed to specify, but rare here in the United States. I know they made 83k of them between 1952 and 1956 but most of those 83k weren't US export bikes. We only got them starting mid '53 and most that came here are long gone. You don't see them at vintage motorcycle shows. Anyway, rare here in the US. Probably much more common in Europe.
@@RobertAdairWorkshop OK that's true, there muight have never been an official importer for NSU bikes in the US.
Hi
Engine looks great
Where did you purchase the new cables from. Decompression, throttle, clutch, speedo, air
Regards
Russell
Hi, Russell. I bought some universal kits from Venhill. Two of their clutch kits and three of their throttle kits. The decomp cable and housing are the same size as the throttle cable. I made the cables myself. It’s pretty easy but requires soldering the ends on.
I forgot the speedometer cable. I got that one on eBay from a seller in Spain. the drive side end wasn’t correct and required me to fabricate a bushing. I can send you a cad model of the bushing if you have the means to make one.
Tha ks for getting back to me, most appreciated.
I have seen some cable kits advertised but worried they may not fit and they are nit cheap. But I will give them ago with the knowledge I may have to adjust them.
Thanks again
Rusty
looks like a 1956 or later supermax , earlier bikes had cantilever rear suspension ,
Yeah, that threw me off, too. When I had the swingarm out, the lever arm for the cantilever spring was there but had been cut off with an acetylene torch. We did a lot of research and it seems this bike was modified by an NSU dealership to fit the dual seat. As part of that, they cut the cantilever arm and retrofitted the rear shocks. You can tell they are retrofitted based on the shape of the shock perch, where it attaches to the monocoque, and the ribbed bracket that supports them on the underside of the rear fender section. The dead giveway to it being an earlier bike is in brake hubs and wheels. This bike has the smaller drums with the single leading shoe. It took a look of research on it and talking with some experts overseas to determine it was a modified 1953 and not an older model.
What paint was used for painting aluminum engine casing?
It’s Eastwood’s Aluma blast
Much better result is with aqua blasting or glass blasting. Paint peals off, changes colour ect. after a while and looks bad.
❤👍👏❤❤❤
Correct me if I'm wrong... didn't you split the cases to check the transmission, main bearings, shaft end play? |n this video anyway it looks like you just painted the cases without taking the whole engine apart, which isn't a rebuild.
I did not pull the gearbox or shift drum apart. Everything else, yes, including bearings, rings and valve train were redone.
OK, thanks for replying. Nice job.
at 5:18 use an Impact driver,, and at 8:17 I presume you lapped in the Valves
I've never had good luck with impact drivers, at least, not the ones you smack with a hammer. They always distort the head which is what I was really trying to avoid here. You're right about the valves. They and thier seats were in good shape and a quick lapping is all they needed.
Die freien Aluminium Teil hätten nicht lackiert werden dürfen. Es verfälscht das originale Design.
I like them painted.
Ridden until the oil ran low.
Typical treatment for a 250. 😢