4 valve
cylinders, heads, and accompanying parts have been around for some time
now. The most popular and well known are those designed by Jim Feuling
and marketed by Rivera Engineering.
I have the eighth set made by Feuling, and have run them since 1990 As a
matter of fact, I did an article on them for Easyriders magazine
at that time.
I like these heads. There has been a fair amount of controversy over
them folks love them or hate them. Those who hate them usually do so
because they never really learned how to set them up or haven't gotten
them working to their satisfaction. The only advice I have for them is
to read the instructions or call some-one who knows what they're doing
and ask them questions.
I have never heard anyone say they were not impressed by the power they
got by simply bolting a set of these on. Of course, when you use
combinations of stroke, bore, cams and carburetion, they really make a
believer out of you.
The most common complaint about these heads seems to be valve train
noise. This is easily taken care of by proper set up and one of the
items usually overlooked.
For most street engines I recommend a camshaft slightly milder than what
you would normally use in the same engine displacement, using two
valves per cylinder heads. The four valve heads flow better and also
seem to prefer this setup. But again, cams are different as night and
day and are as much a rider preference as a seat or handlebars.
Most of the time I recommend JIMS hydraulic lifters, but no matter what
brand you choose, they must be properly fitted to the lifter housings.
For my own personal engines, I make a set of non-adjustable push rods
using material from White Brothers. This means setting up the rocker
boxes and using a set of adjustable pushrods, adjusting them to the
proper length, and then removing them without changing the length,
measuring the length, and making a set like them.
It is time-consuming, but I am more than happy with the results and have
not had any failures. It should be noted that the 0-rings used to seal
the rocker boxes to the head do not have to be changed, provided the
engine has not been started.
