Hello again folks. Took the plugs out of my 2002 748S slabside, (ST4 type heads) they are RA4HC, now, some sites say RG4HC, but more say RA59GC, confused is the word. Any suggestions?, anyone else have the same bike?, which plugs. Thanks Alan.
Unfortunately, I don't have one, Mr Haynes says RA59GC. Just wondered if the spec was different for the ST4 heads on the last 748's, ST4 plug is RA59GC as well though. I'll probably just get those. Thanks Alan.
My manual says Champion A 55 V but I've just noticed yours is an S and mine is an R - but having looked it up and typed this out....... Good luck with finding the answer
Factory manuals state RA59GC as well as the MY02 748 owners manual. Most avoid Champion plugs and go for NGK, some avoid Iridium but many swear by them (I have sworn at them) RG4HC are the ones specified for 998s in the same owners manual Issued for MY02 748/998. If you don't read the manual correctly you might think the RG4HC is the one for the 748
Thanks Folks, great info, and real quick too. I'll bet that's exactly what's happened, a quick scan of the manual and someone has ordered and fitted 998 plugs by mistake. I've ordered the Champion RA59GC. Thanks again, Alan.
Having Testabassa heads on the 2002 748 doesn't change the type of plug to earlier 748s. Not sure though that the plugs for the 998 would be the same as that's a Testastretta. Of note, none of the 748R had the dropped cam heads, even the 2002. I think it's important make sure the plugs that will fit down the head with enough room for the socket
DCR9EIX -- Do you guys alter the gap? Preset to 0.8mm Copper Champion plug in the manual is 0.6mm Anybody run the racing NGK plug , R2525-10
No, I run them with the preset gap. The ignition system is quite capable of firing the larger gap which helps reduce plug fouling. In fact NGK do not recommend altering the gap as the fine centre electrode is easily damaged.
Interesting. Like Derek, I always stuck with the preset gap but I have read recommendations to increase the gap for an even fatter spark. It would be interesting to hear how you get on...