[MOTO BISTRO]

The best way is to completely disassembly the forks for a complete, thorough inspection. If you have had no service done to them in 4 years, replacing the seals now is a lot cheaper, including headache time, than replacing them in 1k miles when they decide to start leaking for no apparent reason. Having a certified tech do this work is always nice, as small changes in fork oil level, compression/rebound adjustments and overall proper reassembly, makes all the difference. Cleanliness is next to godliness especially when it comes to suspension. If I remember correctly www.ducshop.com was running a special for servicing suspension. Its not a difficult process, but suspension experts make all the difference