The Ural/BMW Engine Conversion Page
Athens - Greece
I am the owner of an URAL L650SC (with sidecar) model '95. My question to you is whether i can fit a BMW engine on my bike and if yes , which models' engine . I would like to know if it is a 50s , 60s or 70s engine that may fit . Also if the engine that may fit, has reverse gear and / or shaft for driven sidecar wheel.
If you do not have an answer for any of the above , please let me know to whom may i appeal in order to find that kind of information .
Best regards ,
Marketing & Communications Director
MAD TV S.A. / Television - Productions
/5 /6 BMW engines can be fit to Urals and Dneprs with a little fussing. The motor mounts line right up. The gas tank may need to be shimmed for the petcocks to clear the starter cowling. The Russian tranny is used. The transmission mounts are just slightly inside those on the BMW cases. Usually material is added to the transmission case and the mount holes are relocated to match the motor. The clutch is built up using /2 friction plate and /5 covers. You need to shim the covers to accomadate the thicker /2 plate and you need to make up a new clutch rod to fit the BMW spring plate. The transmission case has tabs to locate it in the clutch housing on the motor cases-these need to be shimmed to fit(Eckhardt sells a ring you can epoxy to the tranny case to do this). You will hear you can't use anything bigger than an R75. My experience is anything smaller than an R90 will yield dissapointing performance. My Dnepr had an R65 in it when I got it. It really was no better than the Russian motor if you fix the weak parts on it. YMMV. My bike has been trial and error and I have no specific measurements to share. Good Luck!
The Red Menace
My understanding is that this can be done but you need to retain the URAL trans otherwise you will have 4 or 5 speeds in reverse & only 1 speed forward. I think that new mounts have to be welded on the BMW engine to accept the URAL trans. Eckard Shultz in Canada is doing this service & may be of some help.
Eckhard Schulz at Moto Retro
400 Colborne St
Midland, Ontario L4R2K4
tele 705 526 2558
he does BMW / Ural conversions
Mike asked me some questions about the clutch assembly on a BMW/Rus bike conversion. Since some of this lists members have been talking about the same conversion, I will post my reply here as well. Please remember I am a shitty mechanic. I only do the work myself 'cause I am too cheap to pay for it and there isn't anybody nearby to do it for me.
my Bneepr was set up by Andy Rainwater, who, until his untimely death was this continents treasured repository of Dnepr parts and wisdom. He used Ekhardts parts for the conversion. Andy mentioned he had some trouble getting Ekhardt to follow through with parts in a timely manner. Still, Meinherr Schulz does know an awful lot about these rigs and it is worth staying on his good side. The write ups of Moto Retro's products and the photos of his bikes I have seen look very intriguing. Some really nice, unusual stuff. I have not ordered anything from him, but we have spoken on the phone. I found him amusing and very helpful. I am sure he would be happy to give you exact measurements if you ask. If he sent you the entire clutch assembly ask him if he turned the face of the pressure plate. It may not need to be shimmed.
That said, I will tell you what I can. Starting from the back side of the engine, the clutch consists of four pieces. The spring, the diaphragm, the friction plate and a heavy cover plate. My parts were heavily modified, and rather than measure them, I fudged bits until they seemed to work. You need the /2 friction plate to fit the splines on the Rusky transmission( remember to lube these splines every chance you get!). I don't know if you can use /2 parts for the rest of the clutch-mine are probably /5, and I have only heard of /5-/6 pieces being used in this application. My cover plate had the face turned AND had washers silver soldered to the mounting holes as shims. If you compare the /2 and /5 friction plates you will see the /2 plate is much thicker, necessitating this modification. Measuring the thickness of the two different plates will tell you what the shim should be. Inadequate shimming will cause excessive spring pressure, resulting in stiff clutch action and premature wear of the diaphragm and clutch rod. I replaced the pressure plate with another one I had laying around. I had a machinist turn a couple of shims for me. Large rings that mate to the outer surface of the pressure plate, much easier than trying to braze washers around each bolt hole. Sorry I don't know the shim thickness( I told him "make one 'bout this thick and another 'bout half that" -machinists hate me!).
You need a clutch rod- the Russian one has a square tip and won't fit the BMW diaphragm. If Eckhardt made you one, can you send me the dimensions? I made mine of the wrong hardness and it has worn short. I need to make a new one but I don't know the exact length(the last couple were "'bout that long"-worked for the shim but the clutch rod is a little more critical). If you lose cable adjustment and the clutch gets real stiff, suspect wear of this part!
If your shifting is sticky and stiff, try loosening the cable a bit. Lack of freeplay shows up first as notchy shifting. If that's not the problem, check your transmission shifter adjuster. I don't remember the exact drill but if you have a manual it will show you how. Not too tough. Check these two things before assuming you have the clutch wrong or diving into the transmission (the same is true for the rest of you Ural and Dnepr owners)! And by the way, you don't absolutely need to fix your tranny shim to the case. It should sit there wedged against the tabs. Gluing or brazing it does make mounting the transmission easier, because you don't need to worry about knocking the shim out of place.
The Red Menace