BMW R25/3, 1953


BMW R25/3, 1953

I’ve always wanted a BMW airhead twin but they always seemed elusive. Then a good friend of mine happened on to this bike and we chased the darned bike all over for a whole day with him swearing that the bike really existed and it wasn’t a figment of his fevered imagination,after all like Dave Barry the Pulitzer Prize-winning American author once said
“There’s a fine line between a hobby and mental illness”. In spite of all the set backs he just kept going and we finally tracked the bike down sitting pretty in an open air garage.Here are some pics of my 1953, 250cc R25/3 when I first got my sweaty paws on her (mmmm…). I guess I will have to progress from a single cylinder to a twin cylinder in time but until then like the McDonald’s ad goes ” I’m lovin’ It” !

The R25 with a welded steel twin-loop tubular frame and a plunger-style rear suspension was a progression via the R23 which was produced by BMW before World War II & later the R24 which was also a 250cc single-cylinder OHV machine with a compression of 6.75 to 1 and a square bore and stroke of 68mm set vertically in its’ alloy crankcase. It breathed through a 22mm Bing carb . All this was set in a rigid frame of pressed-steel bolted together, with an undamped telescopic fork. It had a 4-speed transmission with a shaft driven final drive…a BMW trademark since the very first Beemer hit the streets.

The R25/2 appeared in 1951 with minor changes, mostly to the tin ware and also to the solo seat, this followed by the R25/3 in 1953.The /3 was a better motorcycle, with slightly more power and a better suspension. The fork now had hydraulic damping, with a manual steering damper set in the middle of the handlebar. The fuel tank was redesigned, with a lockable toolbox built into the side versus the previous model’s tank top toolbox. The engine compression was raised to 7:1 with a horse power increase to 13 at 5,800 rpm, and a top speed of 120 kph. It now breathed through a 24mm Bing carburetor. Ignition duties were taken care of by a 6-volt battery and coil, with a Norris generator supplying a constant spark and lights.

Update!!! BMW R90/6

The beemer is a runner alright and she likes to go and I mean does she like that throttle being opened up! She’s a thumper no doubt about it, but of a different sort. There have been some changes that were made by the previous owner to keep her running  (suit his fancy) but nothing that could not be reversed. He gave me most of the parts that were taken off the bike, the only biggish thing that I wished he would have held onto was the seats-his wife threw them into the thrash-nice huh? Anyhow I’m collecting all the bits and pieces that I need to get the old girl back into shape, the upside to it is that they are all available with the downside being that they are darned expensive but then what would you expect of a BMW?! Once I have all the bits and pieces that I need, I will have to find the time of course and you know the rest.

First glimpses….

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2 Responses to BMW R25/3, 1953

  1. james says:

    Never knew they made a single,,,this will be nice when brought back to use.

  2. Pingback: BMW R90/6- 900cc Twin-1975 | oldthumpers

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