Losing any? Oil in the coolant? Leaking combustion gasses past the prechamber? Could be any number of things....

Surging at idle might be indicative of an electrical problem. Disable the electronic governor?

The heat shields look like big washers.

Jay.

__________________
On the road, currently:
'83 300D (German spec.) 168k mi. - - Wolfgang (tucked snugly away for the winter!)
'87 300D 375k mi. - finally went over to "The Dark Side"
'87 300TD 225k mi.
Cannondale 66cm CAAD5 w/Campy/Jamis Aurora
Hujsak Custom Fixie/Landshark Track Shark Custom/Ahearne Custom 29'er