Corroded points plates

[Guest]

Hey all,

I've been trying to narrow down why I only have weak spark off of one coil, and it's led me to this:



It would appear that a fair amount of water has been getting in there and causing some corrosion. I'm not an expert by any means, but this looks bloody terrible compared to the pictures of nice gold plates I see on the web.

Is replacement in order or should I attempt to clean these somehow? I found a fairly cheap set of points plates online, so I'm tempted to just replace them. My only concern with that is setting the dynamic timing...is this something that a reasonably intelligent fellow with some time on his hands could figure out?

[chef1366]

Make sure the cam is good and the advance moves freely.
Replace the points and condensers
Clean up the plate.

[azr]

The manual clearly runs you through static timing, you just need a feeler gauge and some sort of light source for a 12 volt system. If water is getting in there it won't do your points any good while your riding, make sure you fix the leak problem as well.

[billyhoyle]

Make sure the cam is good and the advance moves freely.
Replace the points and condensers
Clean up the plate.

The second two points are clear (and by points I mean your points, not the points on the bike), but I'm not sure what you mean by 'the advance moves freely'. Are you talking about turning the crank with the bolt in the center of the points plate? If so, it turns just fine.

I haven't had a chance to look at the cam yet, but will be doing so at some point in the near future.

[billyhoyle]

The manual clearly runs you through static timing, you just need a feeler gauge and some sort of light source for a 12 volt system. If water is getting in there it won't do your points any good while your riding, make sure you fix the leak problem as well.

New gasket ordered this morning

Static timing I'm not too worried about. Isn't there another process you go through to set the dynamic timing when the bike is running or am I making that up? Setting timing is new to me...

[azr]

Dynamic timing just refers to you using a timing light to set the timing while the engines running. Static timing sets the points and the timing but of course without the engine running. Your bike is going to run sooooo much better with new points and condensers and set properly with no more leaks. Especially in the rain Just a side note, it always helps 'us' if you have your bike in your signature or identify it in your first line of your post.

[billyhoyle]

Ahh gotcha, that makes it much clearer. I'm at least hoping that it will run...it's currently missing that crucial 'spark' component of a running bike. This is a project that I picked up for a song last summer, and it was sitting for quite some time before I got my hands on it.

Signature updated as well - thanks for the help azr!

Hmm, sig isn't showing up yet, but it should soon. Until it does, for reference I'm working on a lovely '77 GS750B.

[Big T]

Your bike has a mechanical advance, spring loaded

Pull off the points plate and grab the cam and see if it moves, it should


When you get to dyanamic timing, rev the bike up and check the spark adavance after the timing is set

That's what Chef meant

[billyhoyle]

Many thanks Big T! I'll report back here after I get some time to look at the advance.

I've ordered new points plates and gasket (not a huge investment off fleabay), so hopefully that helps.

[billyhoyle]

Well it appears the advance mechanism is rusted onto the cam. It doesn't move any which way. I'm going to soak it in some lube for a few days and see if I can get it off and clean it up.

[tkent02]

Try electrolysis for getting the rust off. Great for getting all of the rust off of small parts, or big ones. Do it in a bucket with a battery charger, easy stuff.
Google it, or do a search on here.

Before:



After:

[billyhoyle]

Holy hell, that's amazing! Did a quick google, and it looks like it will be worth the effort to set that up. Thanks for the tip!

[eil]

I also recommend plain old white vinegar for de-rusting small parts. Takes longer but there's a lot less setup.

[earlfor]

Well it appears the advance mechanism is rusted onto the cam. It doesn't move any which way. I'm going to soak it in some lube for a few days and see if I can get it off and clean it up.

The advance mechanism is a slip fit onto the shaft and is removed by pulling straight out. A good soak in PB Blaster or equivalent should free it up. Once removed, you can remove the springs, disassemble it and clean it up easily. Probably the simplest way to clean up the base plate is to remove it and polish it down with a wire wheel.

Edit. It has been awhile. If I remember correctly, to remove the advance unit, which slides straight out from its shaft) you must first pinch the spring loaded advance arms to lift them out of the slot they key into on the shaft. then the whole units slides off the shaft quite easily.

[850 Combat]

If your points cam is rusty, it will wear out the rub block quickly and the points will close up quickly. Looking at the mechanical advancer is a good call, to see if it is Rusty. Some of the old British mechanical advancers wore quickly, but I've never had a problem with a Suzuki one.