Bonneville America Forums Forums Technical Forums Performance Mods Valve shims

Ive just been looking at Pat's site to get an idea on how to do my valve shims. Now from other posts iv'e read about the subject it seems that everyone removes the cams to swap the shims. I don't have the workshop manual yet and it looks like (from the pics on pat's site) our shims are on top of the shim buckets, Am I correct? If so can we remove the shims without removing the cams if you have the proper tool to hold down the shim buckets?

The shop manual says to remove the cams to replace the shims. I've done mine twice now and I really don't see a way to get them out otherwise. Removing the cams isn't that big a deal as long as you hold the backlash gear in place it only takes a couple of minutes.

Yep, what Chy said. Plus, the shims are kinda 'set' into the top of the bucket. You cannot just pull them out. I had to pop mine out. Even if you were able to compress the bucket under the lobe, I doubt that there would be enough clearance...

The reason i ask is because i was reading this article, http://www.dansmc.com/valveclearence.htm
scroll down the page to Shim type adjusters and you will see why i asked.And click on the links in the article to see the pics.

That's an interesting article, I don't see why it wouldn't work. I may have to try to make a tool, since mine need adjusting.

I've heard, though I've never actually seen one, there is such a tool for the 900 engines in Thunderbirds and Legends and the likes and I've seen one that does the Ford overhead cam engines also.

My old CB900Custom had the little tool thingamajig for pressing the valves down. It was easy to swap shims. I did a lot of research and sperimenting and finnaly came to the conclusion that you MUST pull the cams, end of story. The shim buckets do not have enough meat to grip enough to press down with even a custom made tool.
This is the honda tool:


available here if you want to try it yourself.
Chy, you will need one for the 650custom too I believe.

Quote:

---

The shim buckets do not have enough meat to grip enough to press down with even a custom made tool.

---

Yeah I was wondering about that while looking at them. But I'l try anyway. Nothing to lose but time.

Can't wait to see how you get on Bill, keep us posted with your results.

From what I could see from some pics of exposed cams, the inner valve buckets don't have enough clearence with the cam bearing towers to get on them for valve spring compressing (without moving the cams somewhat).

When VW went to SOHC water pumpers in 1974 (Dasher) and 1975 (Rabbit), they used a "shim plucker" tool that resembled snap ring pliers with 45* angle tongs, to pluck out the shims from the depressed buckets. What holds the sims so tightly into the buckets is the oil film.

Thankfully, these Hinckley twins don't need very much valve adjustment, if any. My educated guess is that if anything, the valve clearences should tighten slightly as valves recede. (Valve recession is the sinking of the valve into the head as the valve face and cyl. head seat wear.)

The problem is that the valve and spring are in a well that looks like it is deep enough to prevent popping out the shim from the side.

It'll be a few weeks before I get a chance. I was talking it over with a couple guys that I work with, one of them a toolmaker, gunsmith, blacksmith, and fabricater from way back. Got a few ideas. I'll post my results whichever way it goes.