Thanx for accepting....I have a Pantah NCR replica and use it for Classic Racing in Scandinavia. I´m rebuilding the bike these days with new engine, new frame, wheels etc. The race frame is light and nice, but tube in frame makes spark plug in rear cylinder a really difficult change. Bike is fitted with 800 engine and plug holes are 12 mm wide. I need short spark plugs to be able to fit in between frame and engine. What spark plugs will fit ?
How much shorter do they need to be? I wonder if surface discharge plugs are any shorter than conventional...
Welcome PantahRacer, Why not modify the frame so the plugs fit? Sounds like the bike is in bits anyway.