I got my F2 project bike running two months ago and have ridden it for over 1K miles now. All I did was a thorough carb cleaning and sync. While doing the work, I inspected the existing NGK plugs which are a little black but are otherwise okay so I reused them after slight cleaning.

I got my new Denso (IUH27) plugs yesterday and decided to install them. It was a good time to have a look at the old NGK plugs, anyway. I removed the carbs to do this and looking into the intake ports, I saw oil behind the valves on cylinders #3 and #4. There is a good drop or two collected behind the valves which happened to be fully closed. The liquid looked greenish initially but I wiped it off and it is, indeed, oil. Do I have a valve guide problem? The bike fell on its left side while parked about 2 weeks ago. I've ridden it without any issues. The bike starts every single try. I am not detecting any loss of oil.

When I removed the plugs, there is some oil on the threads of each one. The electrodes had no additional wear from the last time they were checked and the insulator is a slight tan. Except for the oily threads, they looked very good. I installed the new Denso plugs and put the bike together after some cleaning. I can't believe how much better the bike runs now. Throttle response is much better and the engine revs more readily than before. I used Denso iridiums on my S2K also and thought I felt a difference but the improvement on my F2 is much more apparent.

I will take a look at the plugs and check on the oil behind the valves after a few rides but if anyone has any experience with this, I'd appreciate your insight.

Thanks!

 

Id worry about it when your bike starts sucking oil and blowing smoke. Till then, ride on. There is no point in worrying about valve guides.

 

I whole heartedly agree with dissevered. not worth the trouble. you dont even want to know how much you will spend on a valve job... hint(A WHOLE LOT MORE THAN THE MOTOR IS WORTH)