My neighbor came by late last week with a project: Find out why his ATV wouldn't start and fix it. He uses this ATV every single day and it starts and stops constantly. The starter button is actually worn!
After a few minutes of fiddling, it was obvious the starter motor had a burned commutator or stuck brushes. Whacking the starter with a plastic hammer or turning the armature slightly was sufficient to make the starter work for one start, then it would fail to run again without fiddling.
After wrangling the starter out of the bike:
Once disassembled, I got a nice bag full of brush dust out of the end bell. Yep, those brushes are done!
The comm looks a little toasty too:
A new starter is $370 and the armature is not available separately. However, new brushes, brush holders, springs, and seals are available for roughly $65. The existing starter bearings are in excellent shape. Solution: Turn the commutator and save my neighbor a few hundred bucks.
Here's the setup in a tiny Atlas 6" bench lathe. This machine is next to useless for any heavy cutting, but excels at simple maintenance tasks like commutator turning:
The starter gear is padded from the lathe dog by a chuck of Maple and a folded sheet of printer paper:
First pass:
Second pass:
Finished result:
The mica is still low enough that I don't need to do any undercutting. Parts are on order and when they arrive I'll bed in the brushes and get this thing back together!
After a few minutes of fiddling, it was obvious the starter motor had a burned commutator or stuck brushes. Whacking the starter with a plastic hammer or turning the armature slightly was sufficient to make the starter work for one start, then it would fail to run again without fiddling.
After wrangling the starter out of the bike:
Once disassembled, I got a nice bag full of brush dust out of the end bell. Yep, those brushes are done!
The comm looks a little toasty too:
A new starter is $370 and the armature is not available separately. However, new brushes, brush holders, springs, and seals are available for roughly $65. The existing starter bearings are in excellent shape. Solution: Turn the commutator and save my neighbor a few hundred bucks.
Here's the setup in a tiny Atlas 6" bench lathe. This machine is next to useless for any heavy cutting, but excels at simple maintenance tasks like commutator turning:
The starter gear is padded from the lathe dog by a chuck of Maple and a folded sheet of printer paper:
First pass:
Second pass:
Finished result:
The mica is still low enough that I don't need to do any undercutting. Parts are on order and when they arrive I'll bed in the brushes and get this thing back together!
