As the quest for top level performance progresses, our GT750 powered race car continues to be refined. By using modern machining and modeling technology we transformed the outdated GT750 head into a modern masterpiece. The factory head was lacking squish and a proper combustion chamber, the design favored reducing piston temperatures but was prone to head gasket issues and overheating. The spark plugs were also asymmetrical over the cylinders meaning the cylinders ran inconsistently in relation to each other. Ultimately, the factory design was a failure when making power is the goal, and comparable race engines of the time such as the TR750 used centered plugs and a somewhat better combustion chamber designs. Later, squish design and toroidal combustion chambers were developed, but the GT750 was no longer in production. However, these design features can be achieved inside a GT750 head, it requires the head to be welded up, effectively turning it back into a clean billet for machining in the combustion chamber areas. Once that is completed, the head can be machined to achieve designs common in modern 2 stroke racing engines.
As the process is further fine tuned, it will be offered for sale here. The research and development phases were extensive, broaching 100 hours over the last 15 months. The idea is to machine heads to the individual’s combustion chamber specifications, producing the custom head volume and combustion chamber geometry. This requires custom drafting and custom machining. Suffice it to say, the time investment for the design phases is quite large, the machining phases are extensive but not overly complicated. That said, I am still working out the cost to do this for customers, and it likely will be based on the capabilities of the customer. The fixturing is at this point complete, so I can accept any GT750 head. That said, I am not equipped to weld heads, and thus customers will have to take care of that via other means. Additionally, the ideal way to complete this process is to match the head to the cylinders, which requires the cylinder be sent to me as well. This means the new combustion cambers are matched directly to each cylinder, this solves the persistent problem that GT750s experience where the combustion chamber isn’t centered over the cylinder.
Anyways, I have added some photos here that shows the process. If you are customer interested in this process, please feel free to contact me. I’m not likely going to post this product for sale at the moment on my store front as there are just too many variables in the process to set a price. As I learn more about the results of our head work my designs and strategies will likely evolve accordingly as well. So stay tuned!
Hi Chris, I’m just building a GT750 motor for road use and want to use new type combustion chambers, would be interested as to what stage you at at. – Phil
This is a project I can likely complete, but we will have to speak on details. I have sent you an email.