very good advise. i have fisrt hand experience---
i had 1 tank split wide open last june while on vacation,fix that problem with new aluminum tanks.this past sunday we went to the lake for a test ride and lost the upper end of the motor(3 cylinders).pulled the heads sunday afternoon,found the valves gummed up with black crap,other then carbon.
this is a good warning --- please be advised.good luck brawny