Honda 1981 GL1100 interstate Owner's Manual page 93

Problems which may affect Motorcycle Emissions
If you are aware of any of the following symptoms, have
repaired by your local Honda Motorcycle Dealer.
Symptoms:
l Hard stafting or stalling after starting
2. Rough idle
3. Misfiring or backfiing during acceleration
4. After-buming (backfiring)
5. Poor performance (driveability) and poor fuel economy
inspected