Started the R 42

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Darryl.Richman
Posts: 2088
Joined: Fri Oct 27, 2006 3:00 am

Started the R 42

Post by Darryl.Richman »

Yes, these motors are noisy. I believe it's the gear train in front. The idler gear is on an eccentric bolt that was set at the factory and then pinned. If there's any wear, then the connections between the cam and magneto gear get loose. Slabon and Knittel refer to this in their Buyer's Guide when they talk about the changeover to chains in one of the later series of R11s.

But it shouldn't vibrate particularly. It is a boxer, and with a single carb, there's no balancing to do here. I would think it would point at the valves not being set right or maybe a decaying wire or plug on one side.

And of course, "revving it up" is relative, these motors only go up to something like 4,000 rpms.

I think Fred Jakobs wrote that there was some evidence of BMW having looked over a Douglas pretty closely, even before the M2B15 was developed.
--Darryl Richman

olebmw
Posts: 33
Joined: Fri Oct 27, 2006 3:00 am

Started the R 42

Post by olebmw »

ohh, I was hoping my R42 would sound about like my R60/2. Is it all engine noise or is the exhaust loud also?

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Darryl.Richman
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Joined: Fri Oct 27, 2006 3:00 am

Started the R 42

Post by Darryl.Richman »

Yeah, the exhaust is louder than your /2, also. But these motors are pretty rattley, and that's why BMW went to the chain drive on the last R11s and the R12s.
--Darryl Richman

bmwmyplace
Posts: 149
Joined: Mon Feb 26, 2007 6:23 am

Started the R 42

Post by bmwmyplace »

Yeah Dan sounds more like a handful of nuts and bolts thrown into a 5 gall drum then shaken not stirred

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VBMWMO
Posts: 1322
Joined: Sun Aug 23, 2009 7:49 pm

Started the R 42

Post by VBMWMO »

:D well it still runs new pistons, rebore valves guides .... starts easy but hell aint it noisey :( worse than an old Harley Davidson clatter and whiring dont know if Im prepared to rev it up .....certainly vibrates as well, there is no BMW smoothness here my friends...

havent ridden it down the road yet as I waiting on the drive bushes still...maybe tomorrow....

Was looking in the archives and typed in Indian, because there is a similarity whith BMW forks and Indian ones,...and also Douglas and presto there was some photos of both dated 1920 "for technical evaluation"


Peter G
Dedicated to the Preservation of Classic and Antique BMW Motorcycles.

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