I just bought a Savage 21, and after breaking in the engin I find that its not shifting into second gear at all. I am new to the nitro truck arena and need help on the how to adjust the transmission.

I was also wanting to know if there are any sites or anything that can help in tuning the engine. I dont know if i'm doing it right or not. it might be the weather but i have been having probs getting the motor to run smothly. it happens every now and then. I have run a whole tank of fuel through it and it will run great, but then the next time it wont run the same. I'm using a hotter glow plug for breakin, and traxxas 20% fuel.

Can anyone help??? Any help will be much appreciated. thanks.