Well, at least you have to have one cylinder head on. I had been wanting to post this for a while, but wanted to try it first to make sure it worked. It works on my dirt bikes, just wanted to make sure it worked on my SHO motor. It is called an engine lock up tool and Steahly Off Road sells it. Here is a link.
http://www.steahlyoffroad.com/tools/engine-lock-up-tool.html
I drilled a hole in the tool and hammered an allen socket in the tool so that I could intall it in the spark plug hole. Use your hand only to install, no ratchet.

Use a coat hanger to find TDC of the cylinder you chose. I choose #4 in case something went wrong, it would be easier to remove the front cylinder head than the rear.

To remove crank bolt: After tdc is found, rotate crank clockwise about 15 degrees and install lock up tool. then remove bolt with breaker bar. It is that easy!
To Torque: After tdc is found, rotate crank counter-clockwise about 15 degrees and install lock up tool. Then tighten crank bolt to proper torque. Agian, that easy.

http://www.steahlyoffroad.com/tools/engine-lock-up-tool.html
I drilled a hole in the tool and hammered an allen socket in the tool so that I could intall it in the spark plug hole. Use your hand only to install, no ratchet.

Use a coat hanger to find TDC of the cylinder you chose. I choose #4 in case something went wrong, it would be easier to remove the front cylinder head than the rear.

To remove crank bolt: After tdc is found, rotate crank clockwise about 15 degrees and install lock up tool. then remove bolt with breaker bar. It is that easy!
To Torque: After tdc is found, rotate crank counter-clockwise about 15 degrees and install lock up tool. Then tighten crank bolt to proper torque. Agian, that easy.
