by Knowledge » Thu Sep 03, 2020 7:33 pm
The issue with the 225Mugello is that it is a bored-out version of the 200 and the transfers have been set-up for the 200. Due to the angle that they enter the bore on the 200, when the barrel is bored out for 225, it effectively reduces the height (duration) of the transfers. The result is a bigger capacity with a reduced transfer timing.
When I built one at the beginning of the year, I was offered a 58/115 crank. I used a 9mm packing plate which put the A transfers at 122.6 degrees, which was a big improvement over the 116.7 degrees obtained with the 8mm packing plate.
The inlet reduced from 161 to 159 degrees (good) and the exhaust was up from 178 to 182.7.
I don’t recalling doing any porting work as such, and concentrated on getting the squish and CR into the right ballpark.
He saw 76.8mph on his GPS recently.