Originally posted by tiba_karotsu
ok guys i met a customer who's gonna have tune his Jog scooter for sprint racing & he kocht (hehehe incorporating some Dutch words into my posts) an MHR Cross cilinder kit (Mina) & MHR Team krukas with 85mm Ti rod. i opened the box & i behold the barrel has very same ports as Speed cilinder (Mina) & they even have same # (9183) cast on the side of the barrel.
the differences are in the piston & krukas especially on the conrod & the output shaft where the oil seal's "lips" touch the shaft. since the effect of the longer rods reduce port timing (the reason why MHR Cross port timing is milder than Speed with shorter 80mm rod) the rpm/peak power output is moved lower down the powerband making it suited for road usage.
with the MHR Team krukas (85mm rod) you must use an oil seal of 42mm od x 17mm id x 8mm th whereas the MHR team krukas (80mm rod) uses a 42mm od x 20mm id x 8mm th.
again we are talking about Minarelli here & not Piaggio.