I have made various passing remarks about a niggly problem with my ageing GB400. It just rolled 85,000km today and I have had it since new (16 Aug 1988). The main symptoms of the "problem" is that it randomly misfires on startup when idling on choke (I try to keep the revs low) and it backfires (single ear splitter) when throttled off coming to a stop or corner. The misfire "feels" like sudden loss of compresson rather than electrical fault (but wot would I know). Otherwise it goes fine and goes slightly less on a tank of fuel than it did when new.
So I am now wondering if it could be a sticky valve. Any enlightenment would be appreciated:
Is a sticky valve likely/possible?
What would be the symptoms?
Inlet more likely than exhaust?
What are the repair options (other than head off) ie upper cylinder lube (brand etc)?
Does this happen often in bikes?
Add your own question here (with good answer)
Bookmarks