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parts are incredibly closely inspected,
either visually or with magnafluxing, before assembly.
Assume this, so we don't have to mention it on every
step).
The upper case gets machined out, to
accommodate the vastly larger displacement barrels.
At this point, most of the work has been
going on on your crankshaft. First of all, about
three pounds get cut off. With the stock engine,
the increased reciprocating weight will, of course,
increase torque. But with the Cobra, you're
picking up so much of an increase that you can afford to
shed some weight. That decreased weight means that
the bike will now rev faster.
The crankcase is then radiused and
fluted. The fluting will improve oil flow along
the crank surface. It is then balanced and
polished at R.C. and stamped R. C. ENGINEERING.
At this point, the new rods get
installed.
The rod problem was probably the first
big trouble area with Honda 750s. Not so much of a
problem so long as the engine stayed at or close to
stock horsepower. But as soon as high horsepower
started being developed, oops.
Oops meant stretched or broken rods.
Which meant busted cranks. Which meant
busted cases.
Which meant tears.
One of the reasons that this was
discovered so quickly was because of the nature of the
first big-bore kits. All of them, you may recall,
were 836cc. Why that figure? Picked out of a hat?
Nope. Reason was, that Honda 350 pistons and
barrels could be used on the 750. No tooling up
with new pistons for the cheapo manufacturers.
Unfortunately, 350 pistons are domed, and stock 750
pistons are not. Use of the 350 pistons gave a
nice, round compression like about 13:1.
Which meant instant blow-up.
Collins has sort of a rule of thumb -
that when an engine goes over 836cc, 10:1 compression,
or is designed to rev over ten grand, new rods should be
put in
He sells three varieties. First are
his standard hot-rods, which go out for $25 apiece.
Same price for the super |
