How can I believe Tim and Savage? Cylinder Head!

2006 QLink Pegasus 150cc Cylinder Head

This is the condition of the head prior to cleaning:

The red identifies the remaining RTV / Sealant on the problem side of the head.

The orange shows that there are no leaks going into the timing chain cavity. This is important, as if a particular bike did not seal well, coolant could be forced from the coolant passage into the timing chain cavity. This could mean coolant (and lack of lubrication) flowing into the timing chain, and upper end of the motor to the rockers, valve stems, and camshaft.

The yellow in the following image shows the actual leak path between the combustion chamber and the coolant passage. Again- the black residue found here is a combination of burnt antifreeze and carbon deposits. This is a huge image that will show, in an upcoming post, how the aluminum began to suffer fatigue as a result of the hot, high pressure gas, flowing over the sharp edge of the coolant passage opening.

The green circle shows where you should look if you click on the image and view it full size. The blue highlight did not do well in the photo, but if you look at the larger version, you'll clearly see when comparing it to the first image- there is a load of RTV in this hole.

Following a good cleaning, this cylinder head was placed atop a granite inspection table. Using standoffs that are within 0.0002" in height, the entire surface of the head was inspected for warping. This head measured ONLY 0.0005" different from corner to corner! Incredible! No head warping, and it had a few hundred Km put on it (gingerly) since the gasket first lost its seal!