Ural: BMW motor swap and build

Maineiac

Been Around the Block
Gonna be putting together a rig with a transplanted R100 engine in the '96 Tourist. I've been riding it all summer, and haven't even touched the 750 I just finished.
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Dog absolutely loves it! I'm thrilled!
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Here's the rig in all it's glory. I got it stupid cheap, so I don't mind putting some money into making it awesome.
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Picked up a '78 R100 motor. Mileage unknown. It needs at least seals and gaskets. It was nasty as the day is long.
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I cleaned up the motor in preparation for teardown.
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I'll bead blast the barrels after I pull everything apart.
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Picked up a set of 40mm bings for short money. Right carb needs a cable bracket for the throttle welded on.
 
Something wrong with the Ural motor? Or just swapping for the sake of it? Love those sidecar rigs, the Beemer, Ural, Dnepr, Chiang....great bikes (some better than others obviously)
 
Motor runs like a champ, actually. I'll sell it off to finance part of the build. This build has no real timeline. Maybe looking at next spring for a finish time? Who knows? I just needed a new project ;)
 
Funny you mention this. Recently I looked closely at a BMW conversion rig and talked at length with the owner. The one big kink is that the BMW motor is a tiny bit wider than the Ural motor requiring the frame to be spread to get the motor in. Also, the BMW oil filter is located on the lower right side of the motor rather than centered in the front like the Ural motor and the BMW oil filter is covered up and not accessible when the BMW motor is mounted in the Ural frame. The fellow I met pointed this out and said it is a real pain in the a$$ to change the oil filter - the guy said he has to pull the motor mounting bolts, disconnect the drive shaft, remove the gas tank, unfasten the exhaust, and pivot the motor so the oil filter can be changed. I don't remember all the difficulties he pointed out, but there are also some significant fitment issues with the fuel tank/fuel petcocks, airbox, and exhaust that have to be addressed when making the swap. He said it is a BUNCH of work and not just the engine and transmission interface that has to be modified to get the thing to work. This was on a 1997 model BTW. Just some things to consider.
 
If it was easy, I probably wouldn't want to do it. I've got a full winter to realize my dream ;)
 
Here's where the project stands folks!
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If you wanna follow along over at the Soviet Steeds website:

http://www.sovietsteeds.com/forums/viewtopic.php?t=36141
 
Kanticoy said:
Funny you mention this. Recently I looked closely at a BMW conversion rig and talked at length with the owner. The one big kink is that the BMW motor is a tiny bit wider than the Ural motor requiring the frame to be spread to get the motor in. Also, the BMW oil filter is located on the lower right side of the motor rather than centered in the front like the Ural motor and the BMW oil filter is covered up and not accessible when the BMW motor is mounted in the Ural frame. The fellow I met pointed this out and said it is a real pain in the a$$ to change the oil filter - the guy said he has to pull the motor mounting bolts, disconnect the drive shaft, remove the gas tank, unfasten the exhaust, and pivot the motor so the oil filter can be changed. I don't remember all the difficulties he pointed out, but there are also some significant fitment issues with the fuel tank/fuel petcocks, airbox, and exhaust that have to be addressed when making the swap. He said it is a BUNCH of work and not just the engine and transmission interface that has to be modified to get the thing to work. This was on a 1997 model BTW. Just some things to consider.

Without seeing pics it's hard to say for sure, but what about making a removeable fram rail to allow access to the filter? A bit like how they put the removeable top tubes in the CB750 frames to allow the motors to be removed intact.
 
hillsy said:
Without seeing pics it's hard to say for sure, but what about making a removeable fram rail to allow access to the filter? A bit like how they put the removeable top tubes in the CB750 frames to allow the motors to be removed intact.

I thought the same thing, in fact. Unfortunately, I looked at where the splice would have to be made, and it would be right at the forward sidecar mount. I don't know what kind of stresses are imparted there, but didn't wanna chance it.
 
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Ears were welded up, re drilled, then the entire case was machined flat. I'll be using a centering ring and a /2 clutch.

From your thread (concerning the brakes), Whitedragoon, I'm actually in the process of adapting a Nash metropolitan hydraulic drum brake to the front wheel.
 
if you could get another gearbox from let's say Dnepr motorcycle all filter changing issues would be easily solved. Its even stronger gearboxes with reverse. Back here majority of ural drivers changes them. Its identical fit and better gear ratios. Filter housing easy to remove and filter element easy to adapt from some car models.
 

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Whitedragoon said:
if you could get another gearbox from let's say Dnepr motorcycle all filter changing issues would be easily solved. Its even stronger gearboxes with reverse. Back here majority of ural drivers changes them. Its identical fit and better gear ratios. Filter housing easy to remove and filter element easy to adapt from some car models.

I realized that it would have required less machining to get the dnepr gearbox to work. With the dnepr gearbox, I'm told that there's only filing and drilling to be done to relocate the mounting points. The whole gearbox is being rebuilt with new seals and bearings. I'm going to be running the solo gear ratio, so I'm hoping the gearbox will hold up. The new urals use herzog gears in the boxes, so if this one fails, there would be an alternative (albeit expensive).
 
Tim said:
Good to see this one moving along - Bookmarked and Subscribed :)

It's been screaming along, I'm just too lazy to post in multiple forums :)
http://www.sovietsteeds.com/forums/viewtopic.php?t=36141

Seth
 
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Some teaser photos. Take a look at the build thread on SS for more info. I'm pretty stoked with the front drum juice brake. There's also a first start video of the rebuilt R100 motor. Braaap! Braaaap! :)
 
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Front juice brake off a Nash Metropolitan. Lots and lots of custom fabricated bits on this build. It's been my most favorite creation.
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Hound, after an 80 mile ride. Yup, she's hardcore.
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This one is done. R100 BMW swap is complete. Thanks y'all.

Seth
 
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