While discussing with a mate whether to thrash an engine from day 1 or whether to break it in gently, ( not much of a discussion coz I havent a clue what he was talking about ), he said the following 2 things
Just be careful about not pushing car hard enough P. Some cars that are run in too careful get polished bores, which leads to power loss. (Some cars can make 20 or so less bhp from not been run right).
A really good thing to do is a third gear burn. Open it up in third from about 30. Then, at 3/4 max revs just let off throttle and let it slow to 30 again. This causes a vacum in the cylinders that pulls the rings to the bores nicely.
They once did a test in a bike mag I had. 3 bikes. One was run in by someones gran (really slowly). One was run in for first 500 miles, than absolutely thrashed. The other was caned from new.
The 3rd made most power (by 10 bhp or more), but the manufacturer said the engine would not last as long as the others (still more than enough for the first owner however, so let the next guy worry!). The second made good power, and would last ages and ages (and would eventually make the same power as the third, but not for a lot of miles). The first was knacked. No power and could prove unreliable.
Is this right, and if so what does the 3rd gear stuff that improves the engine performance?