Have you had a look at the carby information on the bulletin board area Parts List and repair manual. You will find information on leaks that will be of some help.
I will also put up some information on the motor this week once I have scanned it in.
Sorry but it is taking longer than I thought to get the information up in that area.
Regards,
Bruce
Please do not PM me asking for support. Post on the forums as it helps all members not just the individual.