Has anyone experienced any unusual vibration? (High frequency, not a result of imballanced tires etc.

After about 10 hrs of use my Baja 90 started to produce a very auditable (can hear it) vibration from 20KPH up when under regular load. Under light and heavy loads there is no vibration. When coasting down hill at any speed there is no vibration so it is the engin/transmition. The chain is fine, greased and adjusted as per specs. The oil level is also fine and the engin was not overly stressed during the break in.

The engine sounds fine and has not lost any power. I'm thinking that it could be the transmition.

Any ideas?

 

is you rengine a copy of the honda z50/step thru design?
similiar to this...

http://store1.yimg.com/I/dratv_1860_15725017

if so it could be the two engine mount bolts, these need to be torqued up to the factory specs or they will vcause a vibration

it may be a good idea to replace them with genuine honda bolts/nut's as they also have a tendency to stretch

Karl