Absolute nec. modifications :
tech / Dnepr 650ccm engine
execution of the work described here is for professionals only. A lot
of expensive precise tools and a mechanic who is able to handle them
- disassemble the Engine, clean it, check the whole oil system for
parts that should not be there such as broken drills within oil passages,
pieces of iron in the crankshaft etc.. Once you have removed the oil
pan you will know what I mean.
- check the crankshaft for the right balance and if the connecting rod
assembly REALLY fits the crankshaft (check diameter and angle (!) with
the same screws you will finally use)
- check all bearing seats for correct diameter an angle
- are the ignition timing marks on the flywheel in the right place
(usually they are not !)
- reassemble the engine block with high quality bearings and seals
- trim pistons and connection rod for equal weight for both cylinders
- check the angle between the cylinders and the block
- if you use chromium Piston rings be sure that they are not too hard
for the "softiron" of the Russian cylinders.
- if you are forced to use unleaded fuel replace seat rings, valve guides
and the valves BUT don't use stiff springs for the valves, they ruin
the camshaft within a few miles.
- Finally : DON'T USE the Russian circlip with the piston pin, it works
out and the pin ruins the cylinder - this is the main reason for broken
Pistons and ruined engines.
MAKE your own circlips - best is round spring steel.
If you do this in a professional way the engine
is ready for
trouble free 20.000 km at 110km/h high speed.