Timing a 81 honda atc 200?

i recently bought a 81 honda atc as a project to work on, i had to take the upper portion of the motor apart because it was siezed. i have it unsiezed now, however, i cant time it. I cant get to the crank gear, because i dont have the proper bolts to use the harmonic balance remover. And i cant take apart the lower part of the engine without removing it. Is there any way to time it without dismantiling the lower part of the engine??