Thema Balancer belt

[Chris D.]

Hi,

Just putting mt thema motor back together, and have found a slight prob..
When the motor is cranked on the starter , he balancet belt will gradually work its way outwards untill it is about 6 mm off the toothed wheel, I have reversed the belt
and changed the idler to see if it is different but no..still gradually moves out.
This would indicate that a wheel is out of line ?.
The 3 main wheels, crank and 2 idler wheels would be unlikely to be the culprits its would seem to be the idler, or its cast mounting ?.
Has anyone had this and cured it before ??
Thanks
Chris