BestBear Soviet 2WD sidecars
OPTIONS AND MAINTENANCE
Upgrades and choices

Standards

We build all our BestBear sidecars with a two-leading-shoe front brake for the best result when braking becomes essential.

Front brakes: single-leading shoe brake versus two-leading shoe brake

 

Engines and drive-line components

We also offer choice in our upgraded engines; the 750cc flathead or the 650cc KMZ 650 over-head-valve type and/or an upgraded gearbox.
Rear drive units we can supply, with or without differential locking device, are upgraded with European quality bearings and oilseals.
If you want to convert your own non-driven KMZ Dnepr sidecar combination or solo Dnepr motorcycle to a driven sidecar combination, we can provide you with the complete driveline and sidecar chassis needed to build the vehicle yourself, if prefered including a military or civil type sidecar body. These driveline components are as a matter of course also upgraded to our European quality standards.


Options

Shockabsorbers: although the standard Russian made shockabsorbers are of adequate design, overhaulable and usually up to the job, they do not give the most comfortable ride under all circumstances.
Therefore we offer a choice of several possibilities to upgrade in springs and damperbodies.

The simpliest way is a Russian damperbody, non-adjustable and with modified dampercharacteristics, equipped with a progressive spring of the Dutch make Koni (nowadays Ikon) mounted on the sidecar. This will already make life a lot easier for the sidecar passenger and will give a less bumpy ride when the sidecar is empty. This option is also available as a complete shockabsorber and spring unit with adjustable rebound-damping of the high-quality make Koni’s 7610 series, modified by us to fit to the Russian attachment method.
If you want the very best of all we can provide you with a set of three modified Koni shockabsorber units, each specially adapted to their own purpose. For the sidecar this consists of the Koni mentioned above, accompanied by two Koni shockabsorbers for the rear end of the motorcycle, which can be equipped with a variety of different springs according to the riders preference. This will smoothen out bumps and potholes other makes cannot cope with, while at the same time road stability will benefit a great deal. The Koni shockabsorbers supplied by us will be equipped with green or dark grey impregnated canvas covers to keep the dirt away, thus extending service life.

As an alternative we can also fit specially adapted British made Hagon shockabsorbers with metal covers over their progressive springs, either one for the sidecar or a set of three for the whole combination.
The big advantage of the upgrade with Koni’s, besides the adjustable rebound-damping, is the fact that these are overhaulable while the Hagons are not. Ikon from Australia still produces all spare parts for these Koni’s at reasonable prices.

If parts are not up to the BestBear standards we replace those.

 

Accessories

Besides the standard military equipment which we usually supply our vehicles with - a 10 litres jerrycan in holder, one ammunition box, machinegun holders fore and aft plus a large spade and axe - we can also deliver the original stand for the Diegtiarev DP28 machine gun.
Other accessories are a wooden floor in the sidecar body, extra ammo-box and sheet metal leg shields. We can also offer you the original bakelite emergency light, fitted with a led bulb, and the original Russian black-out device for the headlight, if you wish so mounted with a reflector for the standard Russian or 6V 25W halogen bulb. Caution: in some countries this may not be road-legal.



Although the entire production made in Kiev for the Soviet Army was of fairly good quality, we found some typical material flaws to iron out as well as a couple of parts for which there are far better alternatives available in West European quality.

 

BestBear upgrades

Our upgrades include amongst others a better oilpump and recalibration of the oil distribution throughout the entire engine, better air filtration, German made piston rings, better exhaust valves and reworking of the inlet and exhaust ports, static counter-balancing of pistons and small-ends within less than 1 gramme tolerance and better (asbestos-free) clutchplates. Contact points, ignition coil, bearings and oil seals are also replaced by West European quality parts.

With these modifications our engines are very reliable and smoothly running, also due to the fact that every single part is checked and if only doubtful replaced before we put the engine together again in a well equiped non-production workshop: one man builds one engine at the time, not hastened by production targets. Quality of workmanship is what counts. Quite the opposite of former Eastern-Block production philosophy you might say...

Weighing out and adjusting in a lathe of the pistons.

 

Recommendations

The OHV engines can do with a good 20W50 multigrade engine oil all year round.

In the flathead engines we strongly advise the use of a good quality single grade engine oil, e.g. Quaker State SAE 50 under normal conditions and SAE 30 in cold climate (below 35 F).

For the gearbox a good quality EP 80-90 gear oil GL4 or GL5 will do the job.
The rear drive and differential unit and the sidecar drivebox are best lubricated with Castrol SAF X-J differential oil.
The front fork works best with 0.13 l SAE 10 damping oil in each leg.

Do not convert by Bestbear upgraded engines back to the old original type oilpump. The recalibration of the oilways is carefully adjusted to the higher output of our better oilpump. The old type oilpump won’t be able to cope with that, with insufficient lubrication of the whole engine as a result.

The lower oilscraper groove, beneath the piston pin, must not be used. This benefits the lubrication and cooling of the piston skirt. Our modern profiled oilscrapers are so effective compared to the original design, that lubrication of the piston and cilinder bore would become inadequate should a second one be fitted.

In case the excentrical 6 volt dynamo has to be remounted on the engine it is adviseable to take off the front engine cover in order to re-adjust the gear wheel play on the tooth flanges. Make sure the dynamo gear wheel is on the left, seen towards the front of the engine.

Nice to Know

From the start of the M-72 production in 1941 until the end of the war it was prohibited to suggest (!) improvements for the basic German design, in fear of delay in production. Only in 1944 the frame was strengthened due to frequent breakages and the airfilter changed to the model still used today.

The first production runs in Irbit were housed in an old brewery but because the building was too small some tooling up had been done out in the open (in the Siberian winter!).


During the summer of 1942 not a single M-72 sidecar combination could be delivered to the Red Army, caused by shortages in raw materials and non-useable components pruduced elsewhere. Tyres were one of the main problems.

Also due to shortages during the war sometimes M-72 combinations were sent to the front without paint; these were not expected to survive long enough to rust through.