27-06-13, 08:36 AM
Trimming the end 8-10mm of the HT leads can often cure this sort of ailment. Over time the wire inside gets broken up and corroded where it screws into the plug cap, giving it some clean metal to contact makes a difference. The original plug caps can also develop flaws in the insulation... loads of people replace them with straight NGKs since the OEM ones are a stupid price.
If that and a service doesn't help, then it's possible you have some blocked jets in one or more of the carbs.
If that and a service doesn't help, then it's possible you have some blocked jets in one or more of the carbs.