OK, so I'm going to replace the plugs in my 916. I've ordered a couple of NGK DC9PRE's I don't actually have a spark plug spanner, but no problem I'll order one. However reading on some forums, people have said the NGK plugs have a shorter shank than the Champions and a standard plug spanner might not be able to tighten the plug down properly - seems people have had to grind the outside of their spanner down a bit to get right down to where the engine steps in a bit! is this right? and if so, being as I've got to buy a spanner anyhow, are there any spanner / sockets that will just work "as is" - save me having to modify a standard spark plug spanner...
It was certainly true for my Iridium plugs on my 748 and 998. I have a lathe so machining down a standard socket wasn't too difficult. You could try and buy a thin wall plug socket but it's not a guarantee it would fit, you may still have to skim a bit off.
Cool - my old man has a lathe and he loves anything that requires him to get the lathe spinning, so I'll get him to cut it down if needs be. NB What gap do you use for the NGK plugs? I've heard people saying they run them with 0.9mm as opposed to the Champion plugs at 0.7?
I filed down my tool kit spanner. I ordered one off the interweb but it was too long to fit under a raised 999 tank and wasn't thin wall enough either.
box spanner is the way to go for plugs. i have had a number of bikes where you needed a thin long socket and a box spanner was the only option. I have probably three plug sockets from various sets, I use on the mower, bi-annually
The kit spanner is a box spanner but it's still not quite thin enough and needs to be filed down to reach the flats on an NGK plug inside the spark plug tunnel
It beggars belief that Ducati would supply a box spanner that doesn't fit the bike/plug. Are you sure its the OEM spanner
Ducati spec. Champion plugs so the toolkit socket will\should fit those but NGK's cannot be reached by it. For me it was a quick job to turn the socket down but it does leave the socket wall on my socket quite thin, however it has never failed despite a lot of use.
I have three bikes in the 748-988 range and one uses race plugs which require regular checking for trackdays etc.. So overall quite often and it is a bit of a job. A decent socket makes it easier along with few decent length bar extensions to put on the rachet. Iridium plugs properly gapped do work nicely and I use these on all my road bikes, for me I can feel a slight improvement.
As previously a as previously alluded to in his thread, NGK plugs have the hex flats further down the plug body than Champion and the plug tunnel tapers, so most plug spanners won't reach the flats before fouling the taper.
My kit spanner has cracked withe being too thin but then it's such a tight fit in the taper that it still does the job...
They allow a larger gap, which gives a fatter spark, giving you far fewer low speed misfires, so smoother idle and low speed running, as well as better throttle response AND they last for tens of thousands of miles without having to worry about the plug gap. Win/win
I just used the gap they come set at. I'd have to check what it is exactly but it is a point or two of a mm or two larger than the standard gap with oem plugs. If you reduce the gap to oem, you lose the performance advantage but the longevity is still there of course.
I use 30 Thou. and I believe you can go up to about 35 thou if your ignition is capable of creating a good enough spark. The larger the gap the better is the general rule as long as your coils can produce a strong and steady spark.
