CUSTOM REPORTS
Yamaha XJ650G Maxim-I
A mini-XSU with maximum power and styling 18
Honda CB900C Custom
A triple-threat machine that coordinates performance, distance and styling 24
STYLING
The Midnight Special
A behind-the-scenes look at making the Special special 34
SPEED
Harley-Davidson 74
More oomph for America’s own 38
HANDLING
Dual-Purpose Roadsterization, Part I
Giving a single purpose to a dual-purpose bike 30
BUYER S GUIDE
Headlights
Illuminating facts about all the lamp camps 44
THE CUSTOM FILES
Good As Gold
A one-of-a kind show bike/go bike 54
The Mystery Ship
Vetter’s work of art in living color 58
Cafe Harley
Two continents worth of style 65
DEPARTMENTS
Feature Index 4
Custom Q & A 7
MotoMart 8
The Law 62
Custom Profiles 70
Tricks 72
VENERABLE IS THE WORD generally applied to the Harley 74-inch
motor—quite frequently as criticism for those who are obsessed with
more recent designs such as dual overhead cams and multiple valves.
Harley fans, though, are valid in responding that there is no point in messing
with success. Not only can they point out the fact that the 74 overhead-valve
engine has seen far more exotic designs come and go since its own introduction in
1937, but the point also can be argued that engineering perfection may not need
improvement. Examples such as the Continental aircraft four-banger, the .45 Colt
Automatic or Remington’s manual typewriter are surviving quite nicely.
The only problem is that in this age of hyperbikes the stock 74 can’t be counted
on for regular trips to the quarter-mile winner’s circle. This doesn’t mean there is
no more power in the Harley, as H-D proved itself by reviving the 80-cu.-in. engine
last year, in OHC configuration. Any Harley engine can be increased significantly
in horsepower without impairing reliability because Harley deliberately over-
engineers for reliability.
EXHAUST
THERE ARE AT LEAST as many styles of exhaust pipes for the 74 as there
arc bikes on the road. As a simple rule of thumb, those systems that arc large-
diameter, low-radius in their curves and simple in design prove most effective.
The Harley 62A Staggered Dual system, available from most dealers, is a good
example. These also arc available from many aftermarket distributors, along
with another popular style, the short drag pipes.
Any system should be coupled with low-noise add-on mufflers, since the inter-
nal baffle system, while slim-line in looks, adds little to performance.
LIFTERS
HARLEY USES HYDRAULIC valve lifters which are constantly in need of
adjustment and arc slightly power-robbing. You should replace these with
aftermarket solid lifters, which are practically adjust-and-forget items. Of
course, there will be a slight increase in valve-train noise.
At the same time, the stock pushrods should be replaced with alloy pushrods,
particularly if an aftermarket camshaft is planned.
CARBURETION
GENERALLY, one of the first changes made to a Harley is the carburetor.
Today, this may or may not be necessary. Early-model Harleys, those using
the Linkert carb, can continue to use this stock unit until the engine receives more
displacement. But machines using the Tillotsen carb should have it replaced
immediately, if for no other reason than to make the bike easier to start, better at
fuel consumption and more reliable in general.
Late-model H-Ds using either the Bcndix carb or the newer Keihin will only
need a carb change when massive amounts of cubic inches are added; these stock
carbs do an excellent job of fuel mixing.
While there are nearly as many aftermarket carbs available for the Harley as
there arc exhaust pipes, certain brands have proven their popularity:
The SU. Originally a junkyard modification, specialists have turned the SU into
a highly-tuned, specially set-up unit for the 74.
Mikuni. This carburetor, often used by Harley racers, seems equally suited for
reliability and mileage, as well as for increased midrange response.
Weber (Mikuni-Weber, Solex). Even though this carburetor works superbly...