What caused the problem in the first place?

1. CFMoto applied an RTV or Sealant on the cylinder and head in an attempt to remedy a known head leak:
1. The RTV was applied only from the centerline of the cylinder, to the left side of the head and cylinder housing. This means it wasn't a "for good measure" fix, it was intended to fix a specific problem, or for a specific purpose.
2. The RTV is on the same side of the cylinder that the leak occurred.
3. The RTV is on the same side of the cylinder as the inherent assembly flaw or engineering flaw.
   
4. The RTV applied to the head-cylinder-gasket junctions was counterproductive. It caused more problems than solving them.
1. The RTV was put on sloppily, and oozed into the lower timing chain head bolt cavity.
2. This RTV prevented the proper torque being applied to the lower left head bolt, and allowed torque to relax in use.
3. This may be an individual scooter's issue, or could be commonplace. In any case, this did not solve the problem, and in my case it made it worse.
2. The Stock "acorn nuts" have adequate clearance for the cylinder studs, due to copper colored spacers atop the rocker arm assembly. However, the internal friction between the nuts, the spacers, and the studs is such that prevailing torque precluded a proper final torque value, on the order of 30% of the required torque value.
   
3. The Cylinder bolts are weak. Because of the above condition with the stock hardware, the internal friction adds shear stress (twist) to these weak studs. Under torque called out in the CFMoto Echarm service manual, the bolts torque forward something on the order of 90 degrees with the stock "acorn nut" hardware. This means that when torque is applied and released, the tool will move 90 degrees forward when tightening, but will relax back 90 degrees when the wrench is released. It is possible that some units- even beyond the 2006- could experience gasket leaks due to studs stretching over time. But only time will tell.
4. The left hand alignment sleeve is 0.064" too long. The protrusion of this pin above the surface of the head is something like 0.370". The cavity left in the rocker arm assembly is only 0.306". This means that the head gasket will NEVER become fully compressed. There is a slight lead angle on the sleeve, that may enter into the counter bores a little bit more, but regardless- this is the major reason why the head gasket leaks.

The long sleeve(s) caused the problem. The RTV made it squeak through inspection, but amplified the final problem. The weak studs and incorrect hardware make the entire affair impossible to correctly torque. All together, these three things MUST be remedied in order to properly address the cylinder head leak. Look forward to the next posts for a detailed process and procedure on how to do this.