Honda 110 Transmission and clutch questions

[JV BAJA]

For a college engineering project a group of students and I are building a mini baja car for an S.A.E. Competition. We decided to use the Honda atc 110 transmission coupled with a 10 hp Brigs and Stratton (which is the required engine and must be stock). How can we modify the clutch to engage harder and at lower rpms? We are not sure if the clutch engages based on rpm's or torque. Any info would be very helpful.
If we can’t make this work we need another transmission solution. Any Ideas for a low hp and high efficiency tranny that can take some serious punishment?

[ATCnut]

The auto clutch part of the tranny engages based on RPM. It is a cyntrifical clutch. I am not sure how you are planning to couple your motor to the tranny, it is intergral to the crank in the 110 motor. If you have that part figured out, I might recommend using a honda tranny with a manual clutch instead of the auto clutch setup of the ATC110. Then you would have control of the clutch.

[JV BAJA]

Thanks for the help. We ran the car for the first time just the other day, and it worked better then we hoped. To use an external power setup, we took the cylinder jug off and sealed that opening, a custom power in-shaft was fitted that sticks out where the recoil used to be and has a chain sprocket mounted on it. This comes all the way through the tranny into the clutch. The opening in the case opposite the clutch, I assume where the recoil and mag, were once housed, is now fitted with a cover plate that houses a bearing to support the end of the shaft. Another issue we had was the fact that we no longer had an oil pump. To combat this, the two graphite bushings in the housing were replaced with shell bearings, and we ran a higher oil level to mostly submerge the gears in oil. We were afraid that the increased amount of oil might lead to a higher running temperature, but after testing it proved to make very little difference. We’ve considered mounting an external oil cooler for the tranny considering the amount of runtime this will be seeing, but we need to do more testing before we dive into that. We really need to nail down anything that will prolong the life of the tranny. It has to last for a 100 mile endurance race and multiple other events. So far so good, I’ll check back in when more testing has been done.