Advance Unit Mystery Dust

[YamadudeXS650C]

Hey, I'm interested in opinions as to where this Mystery Dust came from that I found in my 1976 XS650C advance unit (pic 1) when I first opened it up. I am restoring the whole bike. I bought it in running condition with 15K miles. It has a Dyna III electronic ignition (see pic 2). I disassembled the advance unit assembly and everything looks OK upon inspection. I pulled the rod out of the cam from the left side, and it is in decent shape, though it did apparently run out of grease on the bearings; thankfully, the bearing surfaces on the rod are not scored.

So, I found nothing internally that would account for all this dark red dust in the advance area, except maybe the obvious, that is, the coating scraped off the advance weights, which it is, at the surfaces of contact. However, the weights are coated with a copper colored substance, not dark red.

Any ideas or similar findings in your engine?

Yamadude
Central New York XS650 Owners

 

[TwoManyXS1Bs]

That's 'rust dust', flung out of the advance unit. Yours is actually less than I've found in mine. It can be reduced if the advance unit is periodically fogged with a spray oil, like WD-40 or Birchwood Casey's 'Sheath', or Amsoil's Protect...

 

[YamadudeXS650C]

....yes, come to think of it I did find that the posts the weights are attached to were rusty, so i hit them with WD40 after wire brushing them.

 

[TwoManyXS1Bs]

If you want to take it to the next level, you could use 'cold blueing' on the ATU parts. I've used this on my machine tooling, works quite well.

http://www.brownells.com/gunsmith-t...ld-bluing-chemicals/oxpho-blue--prod1072.aspx

 

[YamadudeXS650C]

Cool ! A product I didnt know was available to the gearhead public, and as a gun owner, I am doubly interested.
Thanks!

 

[5twins]

The advance unit backing plate is just plain steel. I keep mine wiped down with oil. After a thorough cleaning, I wipe the whole plate down with oil and lightly grease the weight pivot posts. To maintain it afterwards, I apply a little foaming chain lube to the pivot posts and also a few drops on the springs. I'll re-apply some oil to the backing plate occasionally using a Q-tip.

WD40 is a terrible lube and protectant. Yes, it will free up stuck parts and clean things, but it leaves very little lube behind after it dries. The parts may actually rust up worse afterward if you don't use some other type of protection.

 

[YamadudeXS650C]

Thanks for the input, 5Twins. With a similar sense of the limits of WD40, I decided yesterday to go back in with some Zep45-NC with teflon on the trusty Q-tip (a very versatile tool, isnt it?) . Being an assembly with obvious vulnerabilities, I plan to do periodic checks of the advance unit and rod lubrication, and will consider your idea if needed.

Dissembled the front forks last night; came apart easily (!) but the the stink of the 40 year-old oil was a killer. Wasn't expecting that.