A bit of a SNAFU

So it was several months ago that I got a three angle valve job done and now comes to the time to set valve clearances (or lack thereof).

You guessed it, bolt the cam back in and there isn't enough clearance for a 0.002" feeler.

Readings of the clearances prior to the grind are considered missing in action at the moment... which doesn't leave me with much to work with.

Is there ANY way I can get these valves set to spec with only 1 new set of shims? I can't fathom how to figure it out without buying a couple extra shims about 20-30 thousandths thinner and then mesuring all the valves individually before buying the right shims.

I could measure how thick the bucket is, and how much space is between the valve stem and where the bucket rests, but I don't know how inaccurate this would be for calculating new shim widths.

All the shims are between 0.098"-0.102"

I feel pretty stupid now, any advice for a hasty schmuck?

Edit: I will probably be jumping back and fourth between metric and imperial, I promise to keep track of my conversions:whistle:

Post edited by: nfswift, at: 2006/03/13 19:33

your machinist should have taken the stem length into account when doing the valve work.

meaning, they should have trimmed the end an appropriate amount, and re-radiused them.

--r

What year and model bike are we talking about here?

I would just buy the smallest shim you can then do your math from there.

From the sound of it you might have under the bucket shims, in that case it is a real bummer. Take your time with those cams. Don't need to strip any bolts out.

Post edited by: savedrider, at: 2006/03/14 00:04

Ah, the shop didn't touch the valve stems when I had the head being worked on, don't know what to think about that one.

And it looks like I'll be doing something close to what saverider suggested... lots of wrench turning left before the 650 leaves the garage

I hate hate hate hate hate underbucket shims :pinch:

Is there a spec in the FSM for the length of stem exposed when the valves are installed? This would likely be measured from the bottom of the bucket bore to the top of the valve stem. Minimum would correspond to the maximum shim thickness and maximum to the minimum shim thickness. You could get real close to the right shim thickness by interpolating. You'll find out if the stems are too long as well.

-Duck

Post edited by: Duck, at: 2006/03/15 04:48

I'm not sure Duck, I'll have to check that out.

That'd be great if I could just do the math and have an accurate ballpark, buy a shim a couple size under and begin measuring for the lot of shims.

However, how do you measure stem-top to bucket clearance with underbucket shims? I tried with the bucket off with calipres but the readings were a bit sketchy.

I hope I don't have to get the stems ground as well, ackh.

Edit: Oh yea, I have a Clymers but no FSM. Maybe stem spec will still be included.

Post edited by: nfswift, at: 2006/03/15 14:05

Post edited by: nfswift, at: 2006/03/15 14:05

I have not tried this yet, but it seems to me that it should work.

Why can't you put the buckets on with no shims, then measure the clearance and subtract the desired clearance from that number and the remainder will be the thickness of the needed shim?

nfswift, The KZ1000 Kawasaki Factory Service Manual has a chart that gives you a shim size to install based on the valve stem measurement. I used this method to determine the initial shim size needed and set my last cylinder head up like this. I found when I actually checked valve lash that I only needed to swap one shim for a size larger or smaller (can't recall which). You measure the valve stem length with the valve well empty. Set the valve in place and use the back end of a digital caliper to measure the length in millimeters.

steell wrote:

I have not tried this yet, but it seems to me that it should work.

Why can't you put the buckets on with no shims, then measure the clearance and subtract the desired clearance from that number and the remainder will be the thickness of the needed shim?

It would not give an accurate reading. On a 650 the shims sit on top of the valve with a small ridge all around it, that holds the shim in position. By removing the shim the bucket sits on top of the ridge, not the valve stem.

nfswift, I have a '77 650 Factory Manual. When I get home I will look and see if this shim/stem height chart that George speaks of for the 1000 models is in it. I'll see if I can get a copy and post it.

I have already typed in the stem length vs shim size chart from the KZ1000 manual available in the article I wrote awhile back. I wish folks would try using the Filebase and Articles sections of this site as they contain a lot of great material and are usually organized better than is possible in a discussion forum thread.

Valve Clearance Article

Post edited by: wiredgeorge, at: 2006/03/15 16:36

I can't get the damn site to update my signature, I think I remember having that problem before and just giving up now.

Ah well, we are refering to setting valve clearance on a KZ 650, I'm not sure if the chart will apply to underbucket style shim systems.

Ok, I just checked a GPz750 head, and my idea will work, "if" you have the measuring tools to do it

You would have to measure the distance from the top of the valve to the top of the ridge, and then add that measurement into the calculation.

I think it could be done with a dial caliper (or digital, or even vernier), and a set of feeler gauges.

I'll be assembling a GPz750 head in a couple of days, so I'll do it that way and let you know how it turns out.