Carb bowls, aluminum manifold flanges and valve covers are just a few of the cycle parts that get a little warped over time. Volume Seven shows how to put on a new face for a better seal. Any
questions, comments or suggestions please
contact Bob Cox by phone, text or email.
efore the Japanese introduced grooves
with neoprene seals most motorcycles
depended on flat mating surfaces and
paper gaskets to achieve a good seal.
Unfortunately less than ideal metallurgy
in carburetors and overtightened valve
covers and manifolds do not stay flat
especially after undergoing multiple heat
cycles and vibration.
use a plate of approximately 3/16b thick anodized
aluminum which will fit up to two 8 1/2b x 11b sheets
of wet/dry emory paper side by side - large enough to
reface a Commando timing cover. Check for flatness
with a straight edge and look for light leaking
underneath, or use a feeler gauge. Flatness is
important especially when refacing larger items.
You first need a good
flat surface such as
plate glass or, much safer to handle, a flat
sheet of aluminum or
steel. If you have some
plate glass cut, go with
something thick and have
the edges polished and
the corners rounded.
Begin by scaping off old gasket and thoroughly cleaning surface with
solvent such as denatured alcohol
Use a fresh Sharpie to thoroughly
coat the surface to be refaced.
For aluminum surfaces I
like 400 grit
wet/dry emory
paper. In this photo is 400
on the left and 800 on the right. Use
painterbs masking tape to secure the
paper. Duct tape leaves a sticky goo.
Once you have shiny metal on all the surfaces involved in
sealing, thoroughly clean off the part to remove ALL traces
of emory grit.
Fixing warped mating surfaces on carbs,
valve covers and other parts is
simple with a flat plate, emory
paper and a bit of
patience |
