Need help to identify 1938 to 1940's NSU ?

[aquabike38]

I have an old NSU that was retrieved from the bottom of a lake where it laid rested for 56 years, the NSU is in very good condition after all these years under water, people from motorcycle shops in the US believe it is a 1938 NSU 251 osl, by looking at several pictures, i see there are some things that are different like the seat springs, the 38's i have seen have 2 springs located on the back of the seat, mine has the one spring like the 40's, i have tried to locate the serial numbers under the seat on the frame left side, but i think the tag is long gone and i cant see any numbers stamped into the frame...
I do have numbers that are stamped into the engine block and also the head, these numbers read.....
engine serial number : 630 102
head number: 28649

any help to indentify this bike would greatly be aperciated

[mieteknsu1]

You can add some pictures

[aquabike38]

i am trying to add pics. but the size is to large and it wont let me send, i'm trying to work on them and will post as soon as i can,. thank you

[mieteknsu1]

OK.

[aquabike38]

here is one picture of the left side

[aquabike38]

this is a pic. of after i cleaned it a bit

[aquabike38]

[Spiker]

It is NSU 251 OSL produced after war (100%). Almost the same as pre war model excepting generator (separated from ignition) and ignition (contact breaker on camshaft), engine venting (on primary transmission cover), carburetter (Bing mounted on additional curved tube), new shape rubber knee pads on fuel tank. Handle bar was also changed after war. Probably other electrical devices like lamps are different than in earlier models (Noris?). Driver seat and stand is characteristic for 40's and after-war models. Embossed lettering on fuel tank was used only in late-war and post-war models. Seems original but it can not be excluded that might be mixed with some pre-war parts. Main lacks: tool boxes, carburetter and silencer. Check frame and engine number (in Audi Tradition) and also investigate distributor plate on front mudguard. You should find date of production inside engine casing. It shouldn't be a big problem to restore. You may easily find all needed parts (like fuel tank) on the German market. 80% of parts are the same as in earlier (after 1938) models but might have different catalogue number. Good luck!

[aquabike38]

thank you for your information, ii
'm wondering if there is a web page i can check my engine numbers to verify the year of this nsu ?

[taty]

Try to find frame number under the drivers saddle and send your request to Audi Tradition in Neckarsulm. Here is link to the picture showing where you can find plate with the number: http://www.fotocommunity.de/pc/pc/display/17105211
Here is the address:
Audi Tradition
NSU-Straße 28
D-74172 Neckarsulm
Phone 07132/31-1345
Fax 07132/311720
e-mail: @ ralph.plagmann audi.de