The barrel and piston maintenance is identical to standard iron barrels with a couple of small exceptions. Firstly the barrel is now working a lot harder than the original equipment, cooling is therefore important. It is advisable that the
flywheel has all it’s fins and that the cooling fins on the head / barrel are not blocked by debris or caked in oil / road dirt. Good “running in” is very important to the longevity of the installation. With care and sympathetic use the barrel
will last as long as the originals.
It is advisable to inspect the reed petals for damage every year or so dependent on how often and how hard the engine is used. Replacement reeds can be purchased separately if necessary, replace inlet gaskets to avoid air
leaks when doing this.
Oversized pistons are available up to 66.5mm diameter in increments of 0.25mm. The iron barrel can be re-bored and honed just like the original units.
The installation will require “running in” after each re-bore. We suggest a
piston to barrel clearance of between 0.08 to 0.09mm. The piston measurement is taken from the widest point of the piston. In the case of the piston supplied with this kit the widest point is found at the base of the piston skirt.
A 0.08 to 0.09mm clearance is probably considered a very large piston clearance by most re-bore standards but it has proved very reliable in this iron barrel configuration. Always insure that honing is performed on a proper honing machine (Sunnen or Delapina types) power drill attachments with spring loaded stones do not provide acceptable quality standards for squareness, taper or ovality.