GT185 New Armature blowing blue sparks at the brushes

[carsonwcram]

I finally fabbed up an armature puller to get the old one off and a newer one on the bike.

Here's what's happening:

-put on the new armature and cleaned up the surface that the brushes touch.
-installed new brushes to replace the burn up ones.
-put it all back together.

the bike idles great but anything over 3000 RPM and it blows blue sparks from where the brushes are contacting the armature.

I can't figure it out. any help would be much appreciated.

This is all in attempt to get my charging system to work properly.

[parksie]

Sounds like the brushes are bouncing at the higher revs.

[carsonwcram]

Sounds like the brushes are bouncing at the higher revs.

Ok....what does that mean? What would cause them to do it?

[oldjapanesebikes]

A small amount of sparking with these is normal eh ? It usually is more like a sparkle than big flashes - much as you would notice in any small motor - a power drill for example, or a Skill saw. Just how bad is the sparking ? If the brush springs are tired, it may spark more than it should. Also, I suspect (jabcb will be able to confirm) that if the commutator is either worn or not under cut and cleaned properly you will also get sparking. I have the shop manual on line at this link: http://www.oldjapanesebikes.com/mraxl_G ... index.html" onclick="window.open(this.href);return false;

[Alan H]

Make sure the brush springs are holding the brushes to the commutator and also ensure that the brushes are the same shape as what they are running on. (Put the (very fine) emery cloth rough side to the brushes and gently wear the brushes to the same profile as the comm.

As OJB says, make sure that the comm slots are undercut properly and no 'catches' between segments. Post a pic and we might be able to help more.

If the battery is flat or nearly so, there will be more current running through the comm so the sparks will be more visible too.