Valve shim replacement one cam at a time?

It's time to replace the valve shims in my GT550 (which has a variant of the early KZ550 engine). The valves had clearance but they were close when I put the bike back together during the restoration. I've ridden it (quite hard) for 1000 miles, and it's been great, but now it occasionally cuts when idling. The clutch cable is properly adjusted and the carbs are fine, but I know I must be pushing my luck with the valve clearances now...

I understand that because the shims are so small, the only really easy and convenient way to change valve shims is by removing cams. I don't want to skip a tooth on the valve timing, and I'm not a fan of counting the cam chain links to make it line up, so I thought of this idea. How about tying a zip tie between one of the cam gears and the cam chain, and then painting a mark on a point crossing the cam chain and the other cam gear. Then removing that other (not tied) cam, inspecting the shims, ordering replacements for that side. Then putting the cam back in, lining it up with the painted mark, then doing the same with the other side? Does this sound feasible?

Thanks in advance

I've explained the one cam idea here over the years. No need to even mark anything, although that never hurts. Simply unbolt one cam and carefully move it towards center of the engine and be sure to keep all tension on the front of the chain for the exhaust, and rear of the engine for the intake cam. So keep the chain tight, and all slack in the center, move the cam towards center, replace shims, and carefully replace the cam in position, then done, torque that one and go to the other. Timing is never altered if you are careful. Works on the single row chain, and I've done it for over 200,000 miles if not more. On hyvo chain don't know.

Excellent. Just like I imagined, then. That's going to be how I'm going to do it.

Just out of interest, do you know of any equivalent to this sort of valve-depressor tool (which let's you take shims out without removing cams) which I use on my Yamaha?
www.lasertools.co.uk/product/6519

It wouldn't fit on my Kawasaki 550, but I'm just wondering if there's a tool, perhaps a screw-down one, which will do the same job.

I've heard some use the HAZET 2577-2 VALVE SPRING COMPRESSOR

Correct, modified my HAZET valve spring compressor from 8 valve head to 16 and 20 valve head tool.

Pagala wrote: Excellent. Just like I imagined, then. That's going to be how I'm going to do it.

Just out of interest, do you know of any equivalent to this sort of valve-depressor tool (which let's you take shims out without removing cams) which I use on my Yamaha?
www.lasertools.co.uk/product/6519

It wouldn't fit on my Kawasaki 550, but I'm just wondering if there's a tool, perhaps a screw-down one, which will do the same job.

Take a look at your engine. I believe you will find that the shims are UNDER the buckets. Given that, there is no way to replace a shim without first removing the bucket and there is no way to remove the bucket without first removing the cam. Ed

The Picture i post before you see a KZ 650 head with shim under bucket. You have to remove the cams and buckets for a valve shim change.

Thanks guys for the valve tool information. I think it might be more trouble than it's worth to buy and adapt a tool to use in that way, so I'll just remove the cams instead.

650ed wrote: Take a look at your engine. I believe you will find that the shims are UNDER the buckets. Given that, there is no way to replace a shim without first removing the bucket

That's where you're wrong.
Apart from the tool I posted, which works on bigger buckets and bigger shims on bigger engines, a dexterous person (not me) could do it on this engine using a lever and a metal sliver to push and hold down the edge of the bucket. Alternatively, some people do it by stuffing something like a folded ziptie down the spark plug hole to trap the returning valve (in between the back of the valve face and the cylinder head). Either method would result in holding the bucket down sufficiently to pop the shim out with the edge of a small flathead screwdriver.

On a shim under bucket style engine the cams HAVE TO REMOVED to get at the shims period unless you beam the shims out. And if you ever manage to remove the the shims leaving the cams in place please record the procedure and post it.

If shim under buckets the cams MUST be removed.
Steve

baldy110 wrote: On a shim under bucket style engine the cams HAVE TO REMOVED to get at the shims period unless you beam the shims out. And if you ever manage to remove the the shims leaving the cams in place please record the procedure and post it.

That's a pretty stupid position to hold for ALL shim-under-bucket-style engines. What do you think that device I posted is for?

SWest wrote: If shim under buckets the cams MUST be removed.
Steve

If you're saying that whenever you have shims under buckets you have to remove the cams to remove the shims I can meet that "challenge" if you're saying that's the ONLY way to do it.