GS 550 '79 - tachometer drive on camshaft damaged - possible repairs ?

[Guest]

Hello.
After examination of my exhaust camshaft I discovered that the tachometer drive doesn't look as it should. Simply speaking - it's ground.
So, i've gone to the guy who sells used Suzuki parts. He got like 8-10 camshafts and that's where it gets interesting - every one of them was ground like mine. He says that it's common - every used Suzuki GS 550 he got had a camshaft like that...

20180212_021901.jpg

So here are the questions:
1. Why are all this camshafts so ground ? Is it common ?
2. What is the best think i can do now ? is it repairable ? could this camshaft be regenerated ?

I'll be grateful for any help.

[GregT]

Sit it in place in the head and check how much gear engagement you have. If the centerline of the cam gear and that of the tacho drive align, run it.
What's left on the cam looks like nearly every tacho drive I've seen as far as width goes.
You don't need much gear engagement - it's only driving a cable and tacho.

[Steve]

I did not see any damage in that photo.

.

[roeme]

Neither did I, but I haven't looked at it too closely when I had the cover off last time.

[Stigy]

I'm not afraid of loosing tacho. I'm afraid that if another peace of metal breaks away, it could cause serious thread for the engine, oil ports, cylinder barrels, piston rings etc. It doesn't look good. When i scratched this gear a little bit a small peace of metal has fallen off. That's a big concern for me, as i can see it for now...
Here are photos with all deterioration marked.
20180212_021901_2.jpg

[Stigy]

photo 2:
20180212_021803_2.jpg

[Stigy]

Photo 3:
20180212_021830_2.jpg

[Nessism]

The tach driven gear is in the cover. When installing the cover it's important to make sure the tach gear meshes smoothly with the worm gear on the camshaft or there will be a clash. From the look of the photo someone hamfisted the cover install and sheared off a couple of teeth. I'm not sure if that amount of damage is significant or not.

[roeme]

Ah f!$k, now that makes me worry a little; I just did my very first valve adjustment yesterday. Shouldn't a misaligned tach drive pose significant resistance to getting the cover on? I mean, I kept in mind when installing, but I can't recall to have consciously aligning it – also, the cover did "slip" into place without leaving gaps or requiring me to press down on it.

[Stigy]

So, does anybody know or can tell if that amount of damage is significant ? As far as I can tell the two sprocket don't have any free play, they match quite well and the bottom of the teeth are untouched. Still I'm really not sure what to do about that

[GregT]

So, does anybody know or can tell if that amount of damage is significant ? As far as I can tell the two sprocket don't have any free play, they match quite well and the bottom of the teeth are untouched. Still I'm really not sure what to do about that

Use it as is. The damage is insignificant and there is minimal load on the gears.

[bwringer]

Agreed -- run it.

I've actually seen a couple of these with similar damage where someone jammed the valve cover or a camshaft on without removing the tach drive gear. I haven't seen them cause any further issues at all.

This gear has virtually no load on it, so it's not going to damage anything or get worse.