War and Pieces- Soviet Sidecar Rig Resurrection

Awesome. =:O

So, what's the plan now? Are you going to reuse those cylinders? Can you get all the gaskets you need? We've made our own by laying a piece of gasket material or cereal box over the surface, beating it a little with a rubber mallet to make an imprint, then cutting it out with a razor blade.

Cylinders rebored and new pistons. I had most of the gaskets in a parts cache that came with the bike, and made a couple others out of gasket paper, like you describe. All coming up!

Ahhh, so this thing is already done and you're just posting the photolog episodically. Sorry! I thought it was going concurrently with the build.

Nope, not done by a long shot! But, I'm ahead of the posts. I'm bringing it up to the present soon. I'm working on this when I can...

haha.. I was there a couple of years ago.. rebuilt our K-750 engine. There's only one easy way to get the crank out.. Luckily I got some good input from a friend who has rebuilt several of those engines. The lower conrod bearings was shot on our engine, so I replaced the unit with a chinese made one. Didn't have to machine the crank we used. depending on the model/producer, one may need to machine a flange on the driveside of the crank. The centrifuges are a real pain to clean btw, the debris is almost solid. I put in new centrifuges/ slingers in our engine. Had to pull off the gearbox this weekend, I knew something was going on the clutch. Luckily I did this before too much damage was done, the clutch plate retainer screws had started unscrewing themselves. Have used a stronger loctite now, and have punched the screw heads even harder to lock them to the plate..

Putting the clutch back together was a pain.. but I found a (probably factory approved :) ) way to fix it using some 2*4"s and a clamp..

I like that setup.. more pics of your rebuild would be great, if you have them!
Yeah, that crud in the slingers is worse than bong resin (from what I hear from the youngsters). Actually, with all the work getting the crank out, the slingers were pretty clean. I don't think this motor had a lot of hours on it. Too bad it sat in the weather for so long- that's what killed it. The rear bearing was pretty notchy, though.

Any tips for sliding the transmission shaft into the clutch while the motor is in the frame? It's hard enough on the bench.....

I may have some pics of the restoration..:)

For installing the transmission; I've just used a tube through the clutch plate centers to make sure the clutch plate centers are aligned, and then make sure the splines on the clutch are indexed to each other.. then the transmission just slides in. However I've used old and used clutch plates, new plates may be harder to install.

If you can dig up pics, I'd be really interested to see them. This side-valve stuff is addictive!
I think I just have to be less gentle with the transmission. Did you use any lube on the clutch shaft? On the BMW airheads some people recommend honda moly or white lithium grease (just a tiny bit). I actually dressed the clutch plate slots with a fret file and still they get hung up on little burrs, either in the slots of on the shaft. These parts are ruff!

So finally the case was empty. Time to take the jugs to the machinist and see what was what. I found a little speed shop in Essex, Md that worked on everything from Ford flatheads to Willys jeeps to Mercury outboards. They had never heard of Urals, let alone IMZs, but they seemed interested in something different, so I made plans to bring the parts by.

I had a set of one over OEM pistons in my parts cache. They were covered in preservative Cosmoline, an evil, rank mixture of oil, grease, and wax, then wrapped in wax paper. This stuff reeks and is a chore to get off, even with gas.
They already had rings installed, and I had a set of new gudgeon pins in another glob of Cosmoline.



The pair I had were P1s, which evidently signifies they are the first over diameter. "P1-78.15"mm.

My cylinders measured 78mm at the outside, as deep in as my cheapo calipers could reach, so I was hoping I could use these pistons and save some dough.



So, I packed everything up and carted it over to the machinist.
Time to see how bad off the transmission is.

These M72 have what is referred to as a "crash gearbox", no doubt named for the smoothness of the gear-changes. They don't have reverse like later models, but they do have a neutral finder hand lever that can also be used to shift manually.



Footshifter is a heel toe deal.



The clutch actuation rod passes through the mainshaft. The bell housing was full of sand and muck.



On the other end is the clutch rod actuating lever, the kickstarter shaft, and the splined output shaft.



This round doohickey here fits over the splined output shaft, then a hard rubber donut fits over the big pins there, then the drive shaft inserts into two more holes in the donut, which acts like a cush drive.
There's the clutch rod and bearing, too.

Great Thead! Many thanks for posting all the pictures. I have a 1960 Dnepr, he runs, so no plans to rebuild yet, and seeing what you've been through, I'll try to keep it that way!

Thanks!
There are a few threads about Russian bikes on here that really gave me a jones for one. Roma Dakota rebuilt an MV750, Matman72 rebuilt a Ural 650, and there's another thread about a Dnepr that I can't recall the inmate's name - Novo or something like that. I think he got banned before he finished the bike.....All great threads with a lot of great pics and information.

The splined output shaft, is it just crennelated/splined for an locking interface or is it keyed/cottered?

Looking good J.

Are you coming to the RTE in Mt. Airy on Sunday? Maybe take the airhead hack?

Hey KD!

The shaft inserts into the clutch plates, which are slotted to accept the splines on the shaft.

What's the RTE? I have plans Sunday AM, but maybe later I can get down the road...

http://www.advrider.com/forums/showthread.php?t=767740

Crap, I don't think I can make 1PM. I missed the Mt Royal Tavern get -together, too, looks like. That used to be my haunt, when I was a young miscreant...

Looks like I don't have any closeup pictures of the engine/drivetrain restoration available..just overview pictures.

I didn't need to use any lube on the clutch shaft, I guess the clutch plates are worn enough to fit easily:)

When we picked up the K-750, Eva is looking at her "new" bike:

Looks good.
The lube isn't to get the gearbox on more easily. It prevents wear of the splines during normal operation.

Right- I get that, although it can't hurt getting the tranny installed. I ask because there's a big debate about the use of lube on the clutch shaft among airhead nerds. Some say yes, others consider it verboten, because it isn't in the manual.
I find a little lube is never inappropriate.

Eva looks a little trepidatious....

That looks like a well appointed shop, Arctic! Is that an automobile lift?
What else you got in there?