Valve Adjustment

[MPittma100]

So when should you check valve adjustment? After 25 or 30 years on these bikes should be sufficient, right?

I was checking the lash on a 1980G with 15K miles. The exhausts were around .005-.006, intakes were .0025-.003. A little tight by the specs in the service manual. My question is should these valves be adjusted? Or run it like it is?

I am thinking that there is not that much wear here. But what do you guys suggest?

Thanks, MP

[Tat2demon]

Are you talking about valve shims? They should be done every 4k miles.

[trbig]

Are you talking about valve shims? They should be done every 4k miles.

Hmmm... Taking the valve cover off is a giant pain in the butt... I think I'm probably a good 100,000 miles over-due on checking them.

Since you're there, I'd shim them to the wide side of the spec. They get tighter (Smaller gaps) as time goes on. I simply unbolt the cam I'm working on (One at a time) after finding out the sizes I need. Replace the shims, bolt the cam back down and loosen the other one and repeat.. then throw it back together, being VERY VERY CAREFUL not to drop one of thos little cam cap nuts/washers down into the black hole of the cam chain galley.

[MPittma100]

Shims

Where is the best place to buy the shims? Does anyone sell an assortment?

MP

[trbig]

No idea what happened to the shim library from here or who ended up with it. But most any bike shop that's been around any length of time will probably have them. Just be aware, as I said in another thread, take a micrometer with you. Several bikes (And even cars) used the 29mm shims like our bikes have, but they also made them in a 29.5mm width, and you can't tell the difference with a naked eye... they just won't fit in the shim bucket.

[LoHo]

This isn't really really on topic, but why would an engineer think that a cam needed to be designed for 29.5mm shims when 29mm were around? Just to make it tougher on anyone working on an engine?

[trbig]

I don't know, but if they're anything like the engineers that I work with, they all want to leave their own little mark on the world, so their motto seems to be, "If it ain't broke, screw with it until it is..."