R 4/R 35 carb

[cwf]

Does anyone recognise this carburetter? I bought a box of bits reputed to be an R 35 but this doesn't seem to be the right one either for a pre-war bike or a just post-war.

Unusual parts are the top cover with SUM on. The cold start casting (parts missing). The fuel feed to the bottom of the float chamber not the side.

Other than the long number, there are no identifying figures.

Thanks, Charlie.

[RosyPosy]

it could be from an old SUM carburetor, possibly used on some pre-war or early post-war European bikes, but not specifically an R 35. The SUM marking is a good clue since they were known for making aftermarket carbs for various models.

[Luddite]

I think it's a SUM K-series three-jet carb, as fitted to AWO and as has been said, offered as a replacement for R4 R35. Still available new from various Chinese suppliers.

[cwf]

The only details of carbs I have for that time are :
SUM CK9/22-700 for pre-war R 35
SUM CK3/500 FR for R 4, series 4
SUM K for 1937 R 35
SUM CK 3/22 for post-war (1947-55) R 35
BVF KL 322-0 for AWO 425
BVF KL 324-0 for EMW
BVF KL 325-0 for EMW
(3 = 3 jets. 22 = 22mm)
Since there's no distinguishing number on the carb except the long number, I'm none the wiser. It wouldn't be too important if the engine ran smoothly, but it doesn't.

Thanks anyway, Charlie.

[cwf]

I've found a photo of a similar carb attached to a 1936 R 4, serial number 119817.

Cold start facility, fuel feed to bottom of float chamber, serial number and the detailed carb top are some pointers.