EXUP Worldwide was born from the ashes of the original EXUP Brotherhood – the definitive forum for all those who have interest in Yamaha FZ, FZR, and YZF motorcycles.
Have just taken the plugs out of my owo1 to change them (Nippon Denso X27ESR-U) and am a little worried that the threaded part of the plug and collar below is soaking wet with oil on all plugs! Excuse my mechanical ignorance but this cannot be good having oil in the cylinder can it? Can anyone help calm my fears it couldn't possibly be down to the fact that the ow runs without oil scraper rings could it or am I just clutching at straws??
Tough to say with out knowing the history of the engine. But the OW01 came stock with at the time was a race piston, 2 rings if memory serves me right, and they will lose their seal on the cylinder well before your average YZF750 or FZR1000. The nature of the race beast. Do a compression test. If the rings are bad, be a set of kit pistons, .5mm over and you are set, hone the cylinder ans while the head is off get some head work done and presto an extra 10+ horse power. Yippie!
Cheers Gents
Am going to do a compression test but have put the new plugs in and fired her up and everything seems sweet the odd thing is if the rings were shot I would expect the bike to smoke and there is no blue smoke whatsoever!
I think you'll find the the cam cover lid has whats called "plug tube seals" incorporated into the head/cover assembly, if these weep oil is displaced down the plug tube (hole) and sits around the base of the plug/washer area, what you have is a residue left on the plug as you've pulled it out and the constant heating and cooling thins this oil to run down the thread when extremely thin with heat!
Use a dentist mirror and torch and check down your plug holes for weeping gasket/camcover seals.
on all plugs! Excuse my mechanical ignorance but this cannot be good having oil in the cylinder can it? Can anyone help calm my fears it couldn't possibly be down to the fact that the ow runs without oil scraper rings could it or am I just clutching at straws?? 
