2008 Suzuki LT-A400/F, LT-F400/F ATV Service Manual, Page 202Get this manual
1I-5 Starting System: Carbon Brush Inspect the carbon brushes for abnormal wear, cracks or smoothness in the brush holderIf either carbon brush is defective, replace the brush holder set with new oneMeasure the length "a" of the carbon brushes using vernier calipersIf the measurement is less than the service limit, replace the housing end assembly with new oneBrush length "a" Service limit: 6.5 mm (0.26 in) Special tool0990020102 (Vernier calipers (120 mm, 200 mm))
I649G1190017-03
Oil Seal Check the seal lip for damageIf any damage is found, replace the housing end (Inside)
I831G1190065-01
Commutator Inspect the commutator for discoloration, abnormal wear or undercut "A"If the commutator is abnormally worn, replace the armatureIf the commutator surface is discolored, polish it with #400 sandpaper and wipe it using clean, dry clothIf there is no undercut, scrape out the insulator (1) with saw blade"A"