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Nice Kitchen, what's for breakfast?

 

As turning the brake drums goes . . . As a younger man I worked at a Brake and Front End Shop, we brought our cycle wheels in and turned the drums on the shops

brake lathe. It's a one sided set up so no problem with wheel diameter. Kinda spend for occasional use. Maybe there's a shop near you?

 

Nice job so far, I'm enjoying reading up on your progress.

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Mounting the tyres was much easier than I thought it would be given how rigid the sidewalls are. I purchased three quality tyre irons and borrowed some plastic rim protectors. I suppose I was most concerned about pinching a tube with a tyre iron, but it’s possible to get your fingers in there and push the tubes back out of the way, and keep checking this as you work around the rim, especially near the end when things get tight. Lots of soapy water helps things slide but the irons get a bit slippy to hold. Getting the valve stems lined up and through the holes in the rims can be trial and error but overall it’s pretty easy.

 

I also discovered that mounting tyres is one of those situation where a third arm would be handy and without this you have to watch that an iron doesn’t flip back and hit you in the face, leading to untold humility when your mates correctly point out that you were given a black eye by a wheel, and maybe you should stick to bird watching.

 

I was immensely pleased, the entire job took half a day for the four wheels and I didn’t damage anything. One of my friends in our motorcycle group has a tyre mounting machine with a record of puncturing every tubed wheel that was put onto it, to the point where it’s now only used for tubeless tyres. I took great pleasure in recommending that he exchange this machine for a few good tyre irons. After all, he had suggested that Dneprs make good boat anchors so I couldn’t resist….

 

The plastic rim protectors for tyre mounting do their job, and without them I can only imagine scratches would be everywhere. Once the tyres were mounted I pumped them up with just a little air, then bounced the wheels on the floor, turning slowly to let the tubes fully settle into position before inflating to full pressure.

 

I also used one of those static wheel balancers where you manually spin the wheel, letting it come to rest, then apply stick-on weights to counter any imbalance. I thought this might be overkill on a Dnepr but it didn’t hurt, so I did it anyway. In reality, it would seem better to put some mileage on the wheels before doing this but given half of the wheel drums were not exactly round and in need of turning, the whole exercise was probably a waste of time and I would come back to this again in the future.

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The wheels were nearly complete, I installed new western bearings and seals, a fairly easy process if the bearing races are not murderously tight in the drums and then its just a matter of tapping them out with a hammer and drift. The axle itself serves as a drift for the outboard bearing and its outer race which come out together, the outer race of the inboard bearing meant rummaging through my growing collection of old Dnepr parts until I found something of the right diameter. Of course nothing of the right diameter could be found in the twelve tonnes of old Dnepr parts that I refused to throw away (my theory was that these parts are continuously rusting at a rate unmatched by the components made by any other manufacturer, and this exothermic process was going to heat the shed through the winter. I was probably facing overheating....)

 

In the end, I just made a drift of the right diameter out of aluminum on the lathe.

 

I couldn’t find wheels bearing grease locally that was as viscous as the WW2 tank grease that was used by KMZ. I admired that heavy grease they used, the stuff probably filled gaps and smoothed poor tolerances in the original bearings. You could permanently stick your fingers together with that grease.

 

The front and rear axles were corroded like only Dnepr parts can be and I think the KMZ threading machine had seen better days, so I made a mental note to buy some round stock and machine new ones later. They were straight though and good enough for the moment, but I wondered if stainless steel would be suitable and strong enough, still haven’t gotten to this job yet.

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Like your tyre story :)

I tried to get one on (4" on a 19" rim) and couldn't make it. Probably the soapy water could helped when I think about it.

Took it to a motorcycle dealer (45$ for one tyre mounting). They did a very good job, not a single scratch and the wheel was perfectly balanced, but still, I like to do those things myself.

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I used to balance my tires with a balancer that used an axle riding on precision bearings and you would attach weights as you did to get the wheel to be consistent and not have any heavy spots. Then I tried Dyna Beads one time and got the smoothest ride ever. They are small ceramic beads that you put inside the inner tube. They are free to move around until you build some speed up and they naturally seek out the lightest part of the wheel. As the tires wear the beads migrate and keep the wheel balanced for the life of the tire. I've been using them for years now and don't intend to go back to weights.

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Thanks guys. The beads seem a clever arrangement. The things people come up with just when you think everything has been invented. That said, I had an idea for a sacrificial galvanic block to prevent Dneprs from corroding, but I figured it would need to be changed out weekly....

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It was time to look at the telescopic forks. They were drained and dismantled for cleaning and new seals. What little filthy water-oil mixture was left stank and could have been original, could have been whale oil for all I know, I’ve read that even Honda used it in the early days.

 

The stanchion tubes were pitted where the seals run. I found some used ones on the internet for small money but they were really not much better and I just took the best two out of the four stanchion tubes for polishing.

 

After a light sanding, I tried repairing the surfaces with JB Weld but couldn’t get it smooth so a straight grinder fitted with a 120 grit flap disk was then used to work out the pitting, followed by progressively hand sanding to 1000 grit. I was concerned as always about removing material in case it adversely affected the strength, but I think I took .3mm off the diameter in one badly affected area and compared to the guage of these heavy tubes I wasn’t overly worried. If money was no object I would have had them chromed but that’s very expensive in this part of the world.

 

The stanchion tubes shouldn’t have to be perfectly round or straight, the flexible seals will compensate for mild undulations, but the surface does need to be smooth or the seals will wear. I had the stanchion tubes surfaces finished to a very smooth finish, but by the following spring they were corroded all over again, condensation is a problem in the rain forest environment here. Lesson learned: the stanchion tubes were painted at the factory for a reason, it doesn’t hurt that the seals run on the painted surface and the paint will wear away anyway where the seals travel.

 

It was a couple days of effort before the forks were re-assembled with polished stanchion tubes, new seals and a general cleaning of all internal components. I didn’t know it then but the forks would have to be dismantled again the following spring to re-polish and paint the stanchion tubes, and then take care of a leak that was driving me to madness (‘Dnepr’ must translate to madness in an ancient language, or ‘corrosion’ or some other fitting description).

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Before mounting the telescopic forks the steering head bearings were examined and sure enough, the little ball bearings had worn a serious track into the bearing races and and a couple of the balls were missing. I ordered and installed new ones, making sure that all 24 of the litlle balls were well stuck into the races with grease so they wouldn’t fall out and pass between the cracks in the floorboards like so many other little parts have done. Parts are not recoverable from under my shed, there must be half-pound spiders and other monsters under there. I think the monsters must have found enough parts to assemble their own Dnepr by now, and they will likely get their Dnepr running before I do.

 

I suppose conical roller bearings would have been an improvement over the cheapish ball bearings but this could always be done later if the machine didn’t explode in the first 100km.

 

The tightness of the steering bearings is adjusted by the threaded collar, I snugged them up until they felt right and but I didn’t bend up the locking washer against the chrome nut that prevents the whole assembly from coming loose. I figured I would do that after test riding in case further adjustment would be necessary. Later on I would discover that the steering head assembly had become loose during the test rides. Lesson learned: The lock washer is there for a reason, don’t invite trouble.

 

The component pieces of the steering damper were also cleaned and reinstalled, a simple enough device that was working fine.

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I was getting closer to a rolling chassis and putting the engine back in. I had the frame, wheels, telescopic forks and rear shocks reassembled. Of course the rear shocks didn’t function at all at this point but I was anxious to get the engine into the frame, at least to feel like progress was being made. A year and a half had gone by in this grey Dneprworld, so I reinstalled the shocks as they were but I first replaced the rubber mounting bushings in the frame with new ones, the original ones were distorted and loose. The shocks would be repaired later, I was impatient for a road trial so executive decisions had to be made.

 

The final drive was sitting there laughing at me for all this time. The engine, gearbox and carburetors had been devastated internally from decades of idle corrosion, so I hadn’t been in any hurry to open it up and find more bad news, but it couldn’t be avoided now.

 

I removed the drain plug and a little bit of stinking oily substance came out, but no goo or metal pieces. Well, the great god of KMZ motorcycles in the sky was finally coming around to the idea that I wasn’t going to give up and went easy on me this time.

 

Off came the cover and the internals looked pretty good! Filth everywhere but the crown gear and pinion gear had little wear, although there was a minor bit of pitting on a couple of the teeth. I don’t know if this was the original Ivanic metallurgy that causes this but the pitting was in the contact zone where pressure is high. Perhaps the oil had never been changed and the breakdown in viscosity caused this. Anyway, it didn’t seem bad at all and I estimated there is a lot of life left in the drive.

 

I already had a new main bearing and seals before I even opened the drive as I was committed to new bearings and seals through the entire motorcycle. The needle bearings and input shaft bearings seemed fine though, so with the exception of the alternator bearings these were the only other bearings in the motorcycle that were not replaced.

 

It wasn’t easy getting the main bearing off the driving hub, I welded on something to grip it by and back to the 20t press. I removed the ring gear first so as not to damage it. A meticulous cleaning, new grease and and new gaskets, but I eventually used the old rubber gland because it was of higher quality than the one that arrived from the Ukraine, or China, not sure where the crap really comes from. Ural Zentrale has added quality EU-made rubber glands recently. There is also an important felt seal that prevents oil from passing from the casing side to the brake drum, I didn’t replace this as the old one seemed fine and I’ve given up worrying about every detail.

 

The backlash between the ring gear and pinion gear didn’t seem excessive either, it’s supposed to be 0.3mm maximum but I didn’t actually measure it, and compared to the engine or gearbox I figured that if the drive needed work in the future, it’s not hard to remove and disassemble anyway. A nice bit of engineering altogether.

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