Do you have the Clymer manual? If not, you can find it in the sticky in this section. It includes the Hondamatic version of the 400. Balancer chain should be identical to the standard 400, with the exception that it looks like you'll have to remove the both right side covers to access the adjustment nut.
A forum community dedicated to Honda Twin cylinder motorcycle owners and enthusiasts. Come join the discussion about performance, engine builds, classifieds, modifications, troubleshooting, maintenance, and more!