Since the dry centrifugal clutch does not operate in oil, adding Bell Hammer or Bell Scooter will not cause negative effects.
The final gear box contains metal gears in direct contact, so enhancing lubrication is effective. Adding about 5–10% of Bell Hammer (LS or Gold concentrate) or Bell Scooter can reduce wear, improve oil film strength, and help suppress heat and noise.
However, do not use it in 2-stroke engine oil. In separate lubrication systems it may risk seizure, and in premix systems it may cause carbon buildup.
It can also be safely added to your current Grondeman gear oil. Use 5–10% of the total volume, preferably at the next oil change.