There rules can be interpreted in different ways with noise, it depends how the tester is on the day
![Confused :?](./images/smilies/icon_e_confused.gif)
They tried numerous ways of testing my X1, but when it failed on idle they gave up
This is the official line
Engine Size 1 cylinder 2 cylinder 3 cylinder 4 cylinder
250cc (4 stroke) 5,500rpm 8,500rpm
400cc (4 stroke) 5,000rpm 6,500rpm 7,000rpm 8,000rpm
600cc (4 stroke) 5,000rpm 5,500rpm 6,500rpm 7,000rpm
750cc (4 stroke) 5,000rpm 5,500 rpm 6,500rpm 7,000rpm
+750cc (4 stroke) 4,500rpm 5,000rpm 5,000rpm 5,500rpm
125cc (2 stroke) 7,000rpm
250cc (2 stroke) 7,000rpm
500cc (2 stroke) 5,500rpm 7,000rpm 7,000rpm
In cases where the motorcycle has two separated exhausts the measurement will be taken as above from the median point between the two. The limit at Snetterton is 102db. As you can see its a joke with a four cylinder bike only 500rpm more than a twin cylinder, even though the fours maximum power could be over 16000rpm, where 5000rpm on a Harley based motor and its nearly all over!!