Cossack
Owners Club
info@cossackownersclub.co.uk
For Riders & Enthusiasts of
Ural - Dnepr - JMZ - Ish - Jupiter - Planeta - Tula - Minsk - Voskhod - Riga - MMVZ - MotorcyclesTechnical Tips
Or better known as (Tinkering)
The
Cossack Owners Club offers technical advice that is in
addition to that offered by the manufacturers, importers and the
dealers.
We do not offer specific technical advice here, since a poorly
executed modification can result in danger to the rider, the
passengers and other road users. Advice is given to club members
that includes advice on safety, but even so the user of the vehicle
is always ultimately responsible for the safety of the vehicle being
used. The Cossack Owners Club strives to ensure that any
modification advised on will be safe and that the modifier is aware
of the safety implications of the modifications and also any
possible effect on new (or second hand) motorcycle warranty or
increased wear on other parts.
We do offer a few ideas that may be useful advice on a varying amount of subjects.
Some might be new to you, but the tips are well used. I hope the some of you find them useful to help your servicing and riding pleasure.
The COC does not specifically support the fitment of lesser engines such as BMW, VW or Citroen, but may offer engineering advice to those in need. To ensure safety, the fitment of higher performance engines must be matched with an increase in performance of the brakes and tyres and also possibly other components such as forks and lights.
Select the folder below to see the Tip;
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CLUTCHES |
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GEARBOX OIL |
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FINAL DRIVE (URALS) |
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GENERATOR ALIGNMENT |
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GEAR CHANGING |
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FUEL TIPS |
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BRAKES |
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WHEEL BEARING ADJUSTMENT |
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MODIFYING CHROMED AIR INLET TUBES |
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WARPED CARBURETTOR FLANGES |
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SETTING UP YOUR OUTFIT |
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CHANGING GEAR |
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RUBBER COUPLINGS |
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UNLEADED PETROL |
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FITTING NON STANDARD CARBURETTORS |
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ALTERNATIVE BRAKE LINING MATERIAL |
The
holes in the floating plates elongated? - results in excessive
backlash in the transmission and rattles with clutch pulled in -
drill 6 new holes of same diameter between the damaged holes. Use a
good clutch plate as a template. Carefully clean up the new holes to
give a good fit over the clutch pillars. This can be down many times
before you run out of space!
Slow
gear change? - use 90 grade. This quietens the change and also
quietens gear noise. Modern 'Light EP80' will absorb less power but
will make slower changes. Do not use engine oil in the gear box;
funnily enough it is designed for engines whereas gear oil is
designed for gearboxes!
Oil over
brake shoes? - do not over fill. When it says 'level with the lower
threads' make sure it is, and not nearly out of the top threads!
There is a breather in the unit on the brake side, but it does
depend on the seal and the retaining plate being assembled correctly
to allow any expelled oil to run down the inside of the casing
relatively out of harm's way.
Return to
Index
With too
much oil in the case then oil will be expelled from this breather,
as the casing warms up then the air expands and forces any
over-filled oil out, if filled to the correct level then only air
should be expelled. If still a problem drill a breather hole in the
filler nut and fit a short piece of copper brake pipe in it with a
down turned end. (Dniepers already have a breather). Water ingress
when fording deep rivers can be a problem through a breather - the
cold water cools the casing; this cools the air that contracts thus
pulling water into the case - tough! Military vehicles with deep
water fording abilities have high mounted breathers for their
transmission cases.
Fed up
of having to adjust the backlash every time you remove the
generator? - mark the angular position of the generator with a
permanent marker pen or scriber, before removing it. Align the marks
on re-assembly.
Very
crunched gear change is one less gear-change before the sliding
rings and dog clutches wear out and drive is lost in that ratio and
new parts are required £££££££££. Within reason, change up early and
pause between coming out of the lower ratio and engaging the higher
ratio - change down late and if time allows, slightly release the
clutch between the ratios and blip the throttle to help synchronise
the gear teeth speeds. (Dniepers - note that there is a second
neutral notch on the cam plate between 3rd and 4th!, not on Urals).
Problem caused by big clutch running at engine speed that needs to
change speed at every gear ratio shift.
Leaks
through and out of them? - the tapered fuel taps do leak, but they
can be adjusted to improve things. Often the levers are so loose
that they rotate with vibration! Remove the nut and the lever. With
a pair of needle nosed pliers (or make a special tool), screw the
sunken 'nut' slightly further and reassemble. Do not over tighten of
you will increase wear. Re-assemble, ensuring ON and RESERVE in same
positions!
Worn or
poor performing linings? - get professionally relined with Ferodo
MZ41 material bonded on. This is the same material as used on
classic cars such as Moggies that need all the braking they can get,
it is high friction and high heat dissipation. The linings for
Moggies are per-formed at 8inches, Ural and Dnieper brakes are 200mm
= 7.87 inches which is close enough and use the same nominal liming
thickness. Never try to rivet the linings yourself, if you do not
know why not, then you must not do it! Badly riveted linings kill!
Removed
the locking ring with a 'C' spanner, but having difficulty in
undoing the nut that preloads the bearings with the special tool? -
Put the wheel back in the bike, before fully pushing home the axle,
fit the special tool in between the dust disc and the offending nut.
A little preload on the axle keeps the special tool in place,
allowing the tool to be tapped around with a soft hammer with no
chance of it coming out of the holes and causing damage! when loose,
remove wheel and continue.
MODIFYING CHROMED AIR
INLET TUBES
Chromed
air inlet tubes as fitted to the Dnieper MT9 and MT10-36 can be
easily modified to fit the side-valve M72 and MT12 engines where the
carbs sit closer to the crankcase. The length can be shortened and a
new slot cut to refit the air restrictor lever. The standard rubber
pipe or new ones cut from car water hoses can then be use to connect
up.
These
are the biggest source of air leaks causing weak mixture and poor
running. Here is a method to get them flat cheaply (instead of
paying £££ to get them machined), but it does leave many light
scores that are not important, since sealing compound fills those.
Strip the carb or stuff a cloth down the throat and tape a polythene
bag over the complete carb leaving just the warped face exposed.
Find a concrete paving slab; they are always pretty flat, certainly
flat enough for our purposes. Wet the surface with water. Grip the
carb in both hands, wear gloves to protect your knuckles. Press the
carb flange onto the slab. Use a large 'figure of 8' motion to grind
away the warpage. Check every few cycles for the effect. Adjust
pressure to get a more even effect. Use on your work bench under
surgical conditions if you do not want the neighbours to feel
convinced you only deserve to run a Ural. I use this method, and
others I have done it for are impressed with the results but never
saw the method! PS wash the carb well afterwards!
Set up
your outfit on your concrete slab drive. Resist all temptations to
have your oil stained concrete slabs replaced by nice red brick or
tarmac. You can use the regular grid pattern of the slabs to set up
the sidecar toe-in. Run the bike onto one of the line of joints,
then place a 6 foot plank on bricks touching the sidecar tyre. You
can then easily measure the toe in from the plank to any line in the
slabs that is parallel to the line the bike is standing on.
Every
crunched gear change is one less before you need to cross your
spares dealer's palm with a credit card! Change up slowly, try to
use the awkward heel and toe rocker pedal for better control, try
SAE 90 grade gear oil to slow things down. Change down at low revs
as late as you can.
The
rubber couplings on Urals and Dniepers on the swinging bikes have to
absorb longitudinal motion of the rear chromed fork. On the original
(BMW designed) plunger framed bikes, this coupling only acted as a
pivot and shock absorber. The unwanted longitudinal motion of the
rear forked coupling often punches its way through the rubber if the
shaft cir-clip adjustment is incorrect. Lubricate the rubber with
chain lube to minimise wear, it does not attack the rubber and does
not get flung off.
Modern
unleaded petrol contains really nasty carcinogenic (causes cancer)
substances like Benzine, that in laboratories has to be treated as a
poison. Do not wash your hands in it, do not breath in the fumes,
avoid washing dirt parts (of motorcycles!) in it - use proper hand
cleaner and use a degreaser or paraffin to clean parts (paraffin is
cheaper too). In the days long ago in the USA when petrol stations
had forecourt attendants to fill up the customers' petrol tanks,
many attendants developed skin cancer on their hands after the
change from leaded fuel. (Remember the times when the petrol pump
attendants in the old rural garages with slow pumps had to insist
that the big American gas-guzzling 'yank tanks' had to turn their
engines off whilst being filled, since the pumps could not keep up
with the consumption at idle! - joke). Leaded Fuel
Lead
quantities put into the atmosphere from those of us who still use
good old leaded fuel. (I am lucky that the garage in my village is
one of the few that has the licence to sell leaded 4 Star.) All the
vintage and classic car and motorcycle racing in one year only puts
into the atmosphere the same amount of lead compounds as one flight
of a light aircraft from London to Edinburgh running on high lead
aviation fuel. The amount of lead shot that is shot over the land at
living creatures in Europe by 'Sportsmen' was in 1996 was 30,000
tons - do not tell me that the use of trained hunting dogs is more
environmentally friendly either!
FITTING NON STANDARD CARBURETTORS
Fitting
carburettors from another motorcycle and getting the mixture correct
through the whole range is a long difficult task. You will need a
reliable method to measure mixture strength such as 'Color-Tune' or
lots of experience of tuning carburettors successfully. Considering
slide type carburettors - the mixture for the first 1/4 turn of the
throttle is controlled by the idle jet size and air screw (screw air
screw out to let in more air and weaken mixture), the mixture from
about ? to 3/4 throttle is controlled by the needle position and
profile (lower the needle to weaken mixture), the mixture from 3/4
to full is controlled by the main jet size.
The fuel
level controlled by the float needle position affects the mixture
differently at different throttle positions. The slide cutaway
affects mainly low throttle openings. The little depression in the
top of the needle jet contains the pool of fuel that is collected by
the needle on sudden throttle opening to give enriched mixture on
acceleration. All these effects are interrelated. So on a quiet
weekend, try your hand and ear! just because a carburettor came off
another 650cc twin does not mean it will able to be tuned to suit
your Ural without jet and even needle modifications. Oh yes and also
air cleaner and silencer condition will affect mixture at higher
engine speeds irrespective of throttle opening! The matter of tuning
the even more complicated constant depression or constant velocity
carburettors can be in fact easier, although there are a whole
different range of features that can be changed.
Do not
rely on plug colour as an indication of mixture, it is a lot less
reliable now that fuels contain no lead compounds and do you know if
you have the right plug heat range before you start testing? This is
not to say that you will not be able to get the engine running
reasonably well, but poor fuel consumption, poor starting from hot
or cold, hot running at speed, 'running on' after ignition turned
off, holed pistons etc are all indications that more work is needed.
ALTERNATIVE BRAKE LINING MATERIAL FOR BRAKE SHOES
The drum
brakes on the Soviet motorcycles do not tend to work as well as they
should for their size. After you have done all the usual things to
maximise their performance such as:
Lubricating the cables
Lubricating the pivots and cams
Ensuring
all of brake shoe material is in contact with the drum
Skimming
the drums to make sure they are round
Adjusting twin leading shoe brakes to ensure both shoes contact at
the same time
Only
then consider better brake lining material.
NB
The
friction material suggested here is suitable for the motorcycles in
question when used in the manner for which they were designed. If
you intend to use the motorcycle at high speed, in competition,
carrying or hauling loads higher than specified or for any other
unusual purpose then for safety and product liability reasons you
should either use the standard parts or take professional advice.
Any
relining of brake shoes must be done by a professional shoe relining
establishment to ensure that they are attached to give maximum
safety and performance. The use of incorrect rivets and incorrect
lining preparation will result in poor performance.
Do NOT
chamfer the leading edge of the new lining. A sharp edge,
particularly on a leading shoe, increases the performance of that
shoe. A chamfered edge will stop the shoe grabbing.
Recommended lining material is Ferodo MZ41.
In the
UK it is often used on cars such as the Morris Minor that have
similar braking challenges. Lining material manufactured for 8 inch
brake drums as on these cars will suit our brakes with a drum
diameter of xxxmm.
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