Saturday, March 12, 2016

Ural Engine Assembly - 6

We are well on the way for this to be a ten part series. Van Le, the author of the YouTube videos aka Gobium on SovietSteeds, a Ural forum, suggested that I check axial runout at the edge of the flywheel. I mounted the clutch tool to the engine case then clamped my caliper to it. Using the depth gauge, I can measure the distance to the flywheel at various points around a complete revolution. This is one way to see if the crankshaft is true after installation in the engine case. Obviously if all of the readings are the same then the crankshaft is true. I was originally thinking that I would needed a dial indicator on the front of the crankshaft. This method isn't perfect as it assumes that the flywheel is perfect. I don't know what the range of acceptable runout is but I measured 0.3mm runout. In his video, he measured 0.004". In another video, the runout on a new install was 0.28 mm.

With this latest concern addressed, I went ahead and installed the cylinders, heads, pushrods and rocker arms. Torqued the heads initially to 28 ft-lbs until I do a little research and find a better number, did an initial valve adjustment to 0.003 on all valves and threw on the valve covers just to keep things clean. I had initially torqued the flywheel bolt to 140 ft-lbs as this was the limit of my torque wrench. To get just a little bit more, I tied the engine down to the work bench and with the help of my son, I managed to get another 5° of movement with a 18" long breaker bar. I figure that it's close enough to 170 ft-lbs. There is a washer on the bolt that is bent up against one of the flats to keep it from loosening up.

The next step was the clutch and thanks to Bruce from Ketchikan, it was a straightforward job to install the clutch plates and friction disks. New screws were supplied in the clutch kit. Blue threadlock was applied and the screws were torqued to 15 ft-lbs (no specs are mentioned in the repair manual) as a reasonable guess. The picture shows the clutch alignment tool. It is also a crank that can also be used to rotate the engine.

The next step is to change the clutch rod and the throwout bearing. Since the clutch was replaced, those parts should be replaced at the same time.

This afternoon, there was an Airhead tech session at Bob's garage where work continues on the '78 R80. The cylinders, pistons and heads have come back from Porter's Beemershop, the same place that I had my heads reworked. The parts look like new. The owner is still waiting to get his transmission back. While the pistons were being installed in the cylinders, a quick check of the lifters revealed one bad lifter with some pits in the lifter surface. This would start to wear the cam if left so yet another part needs to be ordered. This bike has been on the lift for quite a while with parts just dribbling in from a variety of sources.

Anyway, this is how Saturday went. Not a bad day...


  1. Richard, are the flywheel teeth really chewed up, or is it just the lighting? Having the engine up on the work bench would seem to make life a lot easier than what I did with Petunia last year.


    1. No, not chewed up at all. But not perfect either. The shiny parts are wear.

      Working on the bench makes it much easier. An engine stand would make it easier to change positions.

  2. Sounds like a great way to spend Saturday to me! I bet getting that .28mm of runout was a comforting find?

    FWIW, Randy here uses red loctite on the screws which hold the clutch cover plate.

    I hope to have the '99 Ural's beemer engine's clutch re-assembled soon after I get some missing spacers. The clutch disk splines on a /2 are the same as the splines on a ural's transmission input spline....go figure. ;)

    1. Initially, I thought that it seemed too high. It is something that would contribute to rapid wear of the clutch and transmission splines. I would have preferred something much closer to zero.