I'm trying to get one of these working for a friend. Model number is MBS220E, but it looks identical to the current MBS 240E. When I plugged it in it worked for a few seconds before coming to a dead stop. On investigation, the drive belt from the motor to the wheel which drives the blade has turned to dust, and the reinforcing cords were wrapped round the wheel. Measuring it up it looks like a 2mm pitch 290 tooth belt, but there is also a 0.08" pitch. I'm not sure it matters, I certainly can't measure the pulley accurately enough to check. The big wheel does not have teeth, not an unusual arrangement as the wrap o the big wheel is a lot more. No idea how wide, 8mm would look to be the max that will fit.
I've got a price from Axminster for a genuine spare, good job I was sitting down. Similar belts are available on the interweb for 1/6 the price. Could some kinds soul who has one of these have a look and see if there are any identification numbers on the belt, it is most unlikely to be bespoke.
Thanks