Altered advance mechanism mystery

[Scooterbrain]

I have a mystery. On my 1970 XS 650 Resto, I am installing the advance plate on to the camshaft at the right side threaded end. I have the correct pin to place in the shaft to align the plate and I see the notch in the rear of the plate which will work nicely I suppose. Bike ran well when I tore it down and it had had the Alternator replaced with the 200 watt brush-less unit and a capacitor in place of the battery but still had the std ignition points in place.

The first issue is that someone "previous owner" has brazed a Pin to the rear side of the advance plate even with the slot and just about 3/16 in above it. It interfaces with nothing and I do not know why that was done. If installed it looks like it will interfere with nothing but it will be quite near the outer edge of the Camshaft seal. Does anyone know why that was done and if it will be an issue ?
Also I noticed that with the New seals " from Mikes XS " being half the thickness of the original ones, are just about even with the locating pin hole in the camshaft. I knocked the seals back so that they had really good contact with the camshaft But it still looks rather close to the locating pin hole in the shaft and I am leery of trying to knock them further back.

Any ideas anyone ?? Thank You !

 

[5twins]

There was originally a pin above the slot on the back of the advance unit plate. I think it's there to stop the locating pin stuck in the cam from flinging out due to centrifugal force. Maybe yours came loose or fell out so they brazed it back in?

The new seals from Mike's are a triple lip design so they do sit out a bit farther on the cam. Whether or not that will be a problem I can't say. There have been reports that they don't work all that well. The old single lip ones actually worked and sealed better.

 

[Scooterbrain]

Well that makes sense. Thank you for the answer. I can go ahead and finish my assembly now.

 

[retiredgentleman]

Scooter.................if you have bought the triple lip "Performance" cam oil seals from Mikesxs, you have just bought junk.
They don't fit well (too thick), and they only last about one season before they start to leak.
Go to www.boats.net and buy the Yamaha OEM oil seals (part # 93101-25044-00) also called S-25-40-6. They are single lip and will last for many, many years, likely decades. Only cost $9.96/pair plus shipping, USD.

 

[Scooterbrain]

Thanks for the heads up. I just bought the whole gasket kit. I don't think that I ordered them separately But i probably did receive Junk... I will order the better ones...............I see after a couple of months working on this thing that an alternate source for parts " other than Mikesxs" is always a good find.

 

[5twins]

Yes, do ask here about anything you're thinking about buying from MikesXS. They do have some good items but it seems more bad ones. And the list of bad stuff just keeps on growing. For instance, I used to highly recommend their fuel line. It was an exact match for the original stuff, nice and supple with a thin wall. The last time I ordered some, normal fat 1/4" type line came. And to make matters worse, I installed some and within almost exactly one year, it split at the fittings and was pissing gas out. Absolute total crap now.