You can do it yourself. It is straight forward but to do it with no risk of swarf contamination in the crank case it is advisable to remove all of the internals (crank, cam, followers etc).
With the components removed you simply have to drill out the governor arm "turret" to tap a thread to take an m8 banjo bolt then flush the crankcase with loads of petrol to ensure you get all of the swarf out.
There used to be loads of articles/threads on this site that would explain the steps in detail but it has been years since I have seems anything.
Good luck. But the crankcase is where the vast majority of race engines take their vacuum from and I doubt this is coincidence! Graeme
|
|