So i spoke to geoff baines whos fettling my R we quickly moved to plugs. as we all know the R comes specified with a surface discharge plug the champion qa55v. now looking through paperwork, my bike currently has Champion RA59 GC and has previously had NGK DCPR9E. both are single electrode plugs the former with a standard gap of 0.7mm and the latter with a preset of around 0.6-0.85mm geoff has informed me that the qa55v may make the bike unwieldy at low revs and feels that an ngk dcr9e ix may be more suitable being a single electrode plug with a gap of 0.6mm ive read that this may be too tight and some swear by increasing the gap for lots of scientific reasons etc that are well covered on this forum already my questions is, if it were your bike which plugs and why im intending to use it for spirited dry weekend miles only no track days anticipated (yet) but i dont want it to bog and splutter when im at the lights or a pedestrian crossing or at the forecourt en route to pouring v power nitro into the tank!
It's iridium plugs that need to have at least their preset gap to deliver any advantage. Otherwise use what gap either Ducati or the plug manufacturer recommends
With the squish set at 1mm on my 853, the surface discharge plug is the only one I can use. I was warned that these plugs foul very easily which can result in flooding the combustion chamber and they are not suited to idling revs. I had not experienced any issues until the first session at Mallory last week when the engine refused point blank to tick over to such an extent that I had to feather the clutch and keep the revs up whilst braking into Edwina's, the hairpin and the bus stop. Several high rev laps fortunately cleared the problem and I had no further issues. IMO I'd stick to the ordinary NGKs. Andy
The preset gap is the minimum and perhaps the optimum. What you really want to do is avoid setting the gap to the gap Ducati recommend as its too small for iridium.
