BMW Airhead Pre Purchase Inspection

There seems to be a type when it comes to Airhead BMW owners; one that is meticulous, takes pride in fixing things themselves and keeps a good record of when maintenance was done. An indicator of this is if the bike comes with the original (or some sort of factory) tool kit. It truly did allow you to take the motorcycle down quite far when it came to roadside breakdowns or home repairs.

Engine

  • Achtung! Ask for service records. Assuming the odometer is correct, it’s easy to line up mileage and what maintenance needs to have been performed. 

  • Place the bike on the centerstand and put the bike in 5th gear.

  • Pull the spark plug wires and then clean around the spark plug before removing it.

  • Rotate the motor over with the rear wheel and take a look at the valves with your flashlight to make sure they are nice and thick on the edge like the edge of a quarter/dime. If they are getting sharp on the edge, it’s getting time for a head job.

  • You can also do a compression test now, you will get different results hot and cold and with and without the carbs off (the correct way to do it), but you can do it with the throttle fully open.

Leaks

Take your flashlight out again and look the bike over for leaks. Common areas are where the push rod tubes interface with the block, rear main seal (seen from below above where the rear engine bolt goes through the engine. The neutral switches also like to leak here. Timing chains can get loud over 60k miles and also cause weird motor issues when the chain slacks. This is also an area to check for leaks. 

Test ride

You should take the bike for a test ride and feel for any vibrations from the motor or chassis. Bike is to be started with the choke on full then turned to half after a moment of idling then off after a minute of riding. Go into fifth gear on a highway or country road at 3000 RPM’s and do a full or close to full throttle acceleration to feel if the clutch is slipping. Some hard braking should be done as well. Rear pedal vibration usually means the brake track is worn on the rear wheel.