Here's an interesting one. Been changing a few bits on my 998 and thought I'd put in some new spark plugs. The original plugs are Champion so I bought the equivalent NGK plugs. CR9EB, went to fit them with the plug spanner from the tool kit and could not tighten them as the spanner winds them down so far then hits the head casting before the plug has bottomed out. So, compared the Champion with the NGK plugs and they are physically different in body dimensions and also reach. Has anyone else experienced this? Useful comments would be appreciated.
Yeah sounds about right, the hex on the NGK's is shorter and further down the plug, I found the tool kit one didn't work or any of my socket ones but I've a few old school box spanners for plugs one of which was perfect for the job
You need to buy one of these https://m.ebay.ie/itm/Sealey-AK6557...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
I had the exact same issues with changing brands. I got an old spark plug socket and tapered/chamfered the end with an angle grinder, to fit in the head. Worked a treat.
This is a (well) known issue with NGK plugs and as has already been mentioned a thin wall socket or a socket machined down to fit will do the trick. There is one make of Japanese plug, Nippon Denso, where although correct in every other way the shoulder of the plug is such that fitting them in a Ducati head is impossible! So at least with NGK plugs there is a simple enough solution.
Just buy the aforementioned Sealey socket. The well the plug sits in is tapered, so standard sockets foul the taper with an NGK plug as the hex flats are located further down the body of the plug than with a Champion equivalent. The thin walls of the Sealey socket allow it to slide far enough down the tapered well to grip the hex flats perfectly. As NGK plugs are better and cheaper than Champion and the Sealey socket is great quality and just a few quid, it's a win/win no brainer.
I fit the Champions 9/10 times. Saves the aforementioned problems if customers take the plugs out. Also, the NGK tip is set deeper into the nose of the plug and may shroud the spark a little once in the head. Other alternative is a NGK MAR9 out of a MTS/Diavel. The thin plug socket is a must though if you're set on NGK. I'm not a great lover of Champion but the Testastretta heads force a change. Not had any issues.
