Pictures taken 11/25/2003
 

Time to open up the cases and inspect
for damages. 

Left side Motoplat looks OK, that doesn't
say much about how well its going to work.
 

Primary drive gear allows reduction, lower 
left gear is jackshaft driven.

Left side Motoplat, as with most other
components, left side showed more
damage than right. This side had a
coating of rust that turned the 
ignition system almost orange in color.

Right side covers off, showing a classic
Yankee design problem, that is, if the
bike throws a drive chain, there is a 
good chance it will wedge, and crack
the engine case, requiring welding
and machine work to repair.

New Renthal bars have been added to the 
bike, big difference, lower rise and
not as swept back as the old bars.

There are a few options for how the bike can 
be restored. First - factory original, very
little discussion needed there, this is most
likely the way it should be done. There is no
doubt that a quality restoration to
factory is the most valuable bike to have.

But, I had a factory bike for 2 years, and now 
am thinking about some changes to make the
bike suit me a little better.

One option is to switch the bike to a 180 degree
firing order, like a street bike. The engine may 
start a little easier, make more power higher up
in the power band, and sound different. With the
factory expansion chambers, this may be the
ideal combination for street / trail type of use.

Other choices include polished cases instead of 
painted black, as in Ossa and Bultaco. The
expansion chambers may also look good in 
chrome, like some other classic chambers.
They look good now in polished steel.

Another step would be to replace the IRZ
carbs with Mikunis. Again, easier 
starting both hot and cold, more reliable, 
and easier to service / tune.

Once the bike is finished, it will be my daily 
rider, so it has got to be reliable. If it's 
possible, the electrical system will be 
upgraded from 6 volt to 12 volt, and a 
bright halogen headlight added fo safety.

Part of the reason for these pictures is to
help sort through these options, and determine
what might look best on the finished bike.

One of the steps to add to the reliability and
durability to the motor will be to have the main 
bearing throws machined to accept larger 
connecting rods. The Ossa 250 engine design 
started from a 160 cc motor, and the rods 
are considered to be a weak point for anything 
beyond a mild state of tuning or riding.

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