Friday, 14 November 2014

Lowering height of cylinder as an experimental alternative to a longer conrod -required due to lower piston compression height.
Not easy when the task is just on the border of the capacity of my lathe. Low speed is the answer though.

Always seems a shame to have to strip everything apart at the end of the season but I am putting in a different engine so everything within the cradle must come out. I have tried doing it by leaving the gearbox in and raising the engine but it is more trouble than it is worth.

Having recently bought an old oil pump  found it to be seized through not used. This is very common as the main body is made from Mazak- the British trade name for Zamak. It is an alloy which shrinks with extended age. This feature is fine if used regularly as it takes up wear on the pump wheels but leads to seizure if left idle.
It was used due to being cheap and very easily die cast- being zinc based- for jobs like this. The only solution I have found is to dismantle the pump with great care - heat the body so that it is too hot to hold ( it is cold in the photo!) and use circlip pliers and much metal polish such as Brasso to free each impeller wheel round and then when each is done do it for the assembled pump.

Wednesday, 5 November 2014

Now that the season is over and work can start on the bike I decided to build a new engine with a lighter flywheel after having much thought over the pros and cons of flywheel weight. There is much in the way of arguments for ' heavy' as the momentum gives explosive acceleration due to the kinetic energy stored in the flywheels when the lights turn green.
However I am experimenting with a badly corroded set of flywheels so they would have needed dressing anyway. I loath turning cast iron as it comes off as crumbly dust which gets everywhere. I have heard of people trying a magnet at the tool to try and collect it but I just brush it down.