ORIGINAL: sam123
Thanks for all the help guys

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So I guess the piston and liner should be ok as long as I use more oil than usual. Maybe once I get it going I could experiment with different fuel-oil ratios and oil types.
Nikolas, the engine I plan on converting is a Thunder Tiger .21 Pro. Apparently it is a re-badged OS engine. So, the quality is not too bad. It has not been used much, but has already been broken in on 5% nitro.
Jezmo and captinjohn, I am fairly confident that the carb will be ok. It dosen't use the same 'click' system as the plane engines, but fully adjustable screws like on the weed eater engines. I do have a few spare walbro carbs, but the smallest I have is from an 18cc weed eater, so it would probably be too big.
And yes I know what you mean about being careful with the cdi

. Ive been shocked a few times by my weed eater engines and wow did it hurt.
Also, captinjohn, I will have to take a look at that engine you speak of! Sounds very interesting . And thanks for the link.
I have another question for you guys: How much does the entire cdi system weigh, including the battery (approximately)? Could the cdi be run off the reciever battery if I use higher capacity cells?