Hey all,

Just adjusted the valves on my twin. Piece of cake compared to my old 4-cyl -16-valve.

Reading the measure procedure, the manual calls out very specific crank angles for measuring, with the lobes facing something like 90 degrees to the valve shim.

The way I've always done this is to measure around the lobe circle with the valve off the lobe (about 90-180-270 from the lobe) and use the smallest measurement as the clearance. Is this the wrong way to go about this on this engine?

Also, I ended up improvising a valve tool, using an old Progressive shock tool and part of the valve toolset from a CB900F. The CB900F tool is too narrow; you need a tool 1/4" wide to hold down the bucket.

I sawed the end 3/8" off the shock tool to get rid of the nub and shorten it a bit. I then ground the curved part of the tool down to 1/4" wide from the previosu 3/8". This can't be used to open the valve, but it's enough to hold the bucket down while rotating the crank. With the bucket held down, I use the screwdriver tool (looks like a short, bent flat bit screwdriver) to pull the shim out of the bucket.

I figure most ppl have one of these tools laying around that they can sacrifice for this use. Don't think it's needed, but I can supply pics if anyone is interested.

I'd love to get a diagram with dimensions of the correct valve tool so I can make one. Anyone?

Here's some pics. The modified Progressive tool is scanned on engineering paper; each little square is .2", so 5 are 1". The curve was ground to 1/4" width along the curve. The tools is 1/8" metal. Main thing, when grinding this, is that you want the edge touching the bucket to be flat and square. This tool worked well for what I had into it; 15 minutes or so.



The Honda tool is shown for reference; the tip's a little under .2" wide, maybe 3/16". Angle more or less as shown. It's just a photo, after all.

I also use an old Honda tool to depress the bucket and an old screwdriver to hold it down, can be done with 2 screwdrivers easily if you don't have the GS tool or an old Honda wedge.  Didn't like the GS500 tool I bought.  Check valves with camshafts set like shown in manuals and crank on timing mark for best results.  Has worked for me for 150k GS500 miles.  If you keep enough exhaust valve clearance you won't be changing many shims over the years.

http://img.photobucket.com/albums/v443/jcp8832/ValveShimTools.jpg

http://img.photobucket.com/albums/v443/jcp8832/valveclearances.jpg

Yeah, I saw that posting on the screwdrivers and the old Honda tools. I have the same one and found that it wasn't wide enough either.

I couldn't get the screwdriver to hold the bucket down; now I see from reading it again what I was doing wrong. I was trying to keep the screwdriver in place while rotating the cam, which is something like impossible. I think what you're suggesting is using the 1/4" screwdriver to further compress the bucket while off lobe and slightly held down with the Honda tool or similar.

I used the 1/4" width as guidance to form the tool above. It works pretty much like the old Honda tool, in that you rotate the cam to compress the valve, and keep it spinning to take the valve off lobe.

I'm going to be back into this engine soon; the exhaust valves were tight and with a smaller shim, are still on the tight side. I'm going to let it bash out the carbon for a few hundred miles and check it again this winter.

I've used the 2 screwdriver method and I like it, but just taking the camshafts off is pretty easy too.