I traded off my 76 MC5 125 for a 73 Jackpiner a couple of weeks ago. This is the bike I always wanted. I took it for a ride last weekend. It is very fast and I love the way it handles. It has some carb issues as it wants to load up on low end if you are not careful. I may change the Bing to a 30mm Mikuni as I have a brand new one sitting on the shelf. One thing I noticed on this bike while inspecting it is the bolt that secures the head to the cylinder between the rear cylinder studs is missing. I tried to put in a new one, but it feels like the old one is broken off inside the cylinder. I took it for a ride anyways and there is no signs of leaking around the head. I don't feel real good about this bolt being gone, but I am not sure how bad it needs to be there. Has anyone experienced this problem? Am I playing with fire to run the bike without it? The bike is on the POG registry. I was told that it had belonged to Clay Light at one time who is a member. Happy to have a Jackpiner!!!:)
Doug Bridges
73 Jackpiner
Doug
Most likely it is a 7mm bolt, strange but true. You can remove it and install another and should have no problem. I have though seen engines ran without them. If it were me, I would remove the existing bolt, chase the threads and install new. KTM wanted it for a reason but they should have went with a 8mm instead. Good Luck