Bench setting of valves after rebuild 1982 GPZ750

Just got my cylinder head back from the machine shop, and I wanted to set the valve clearances off the bike. I'm pretty sure I will have no clearance at the exhaust valves due to extensive seat refinishing, (lots of pits I was told.) Could anyone explain the basic procedure? Thanks in advance, Mark

I'm assuming you have a factory service manual.

It's harder but you have to keep loosening the cam bearing caps to rotate the cam(s) so their lobes are pointing away from the valve stem...

However, the most important things to do is only install one camshaft at a time or you'll drive an intake and exhaust valve head into each other and bend one!!
And, make sure you block the head well off your workbench and at it's far ends out of the combustion chamber area or you'll drive a valve head into the bench top and bend one that way too.

You can use some weaker springs to make the adjustment easier. Just be sure to reinstall the correct ones before reinstalling the head.
Why do you want to do this before installing the head?

Were the valves "tipped"? It might be a good idea to check the clearances before it goes on the bike.
Steve

Maybe start with the smallest shims you have and follow Missions advice so you don't end with any bent valves....... I almost did it flat on the bench till I searched on here and found out to raise the head. Was some what of a pain cause you have to remove them and move them so many times (part of the reason I installed heli coils in all of em) I even made a little set up out of wood at an angle and dowel pins to hold it but that was a little over kill.......... Remember no more than 70 to 85 "inch Lbs"...... I go with the lower figure.

My clearances stayed within .0005 on a couple and no change on the other 6 so I didn't have to change any till 500 miles.....then I only had to change 2 ......1 shim size on the ex side only.

Thanks for all of your advice, Mark

+1 on Swest's comment, if the seats have had to be altered significantly it's possible the valve stems could be too long to work even wit the thinnest of shims, that's a good reason to check the clearances before putting the head on in case the valve stems need trimming.

Yes I agree, Thats why I'm working with it off of the bike.
The intakes were fine, hadn't really changed from before the valve job, but there is no clearance for the exhaust valves. Right now the shims installed are 2.40. How many sizes down should i order to be in the ballpark? Thanks, Mark

Madtrout wrote: Yes I agree, Thats why I'm working with it off of the bike.
The intakes were fine, hadn't really changed from before the valve job, but there is no clearance for the exhaust valves. Right now the shims installed are 2.40. How many sizes down should i order to be in the ballpark? Thanks, Mark

You need one .200mm shim which is the thinnest and use that to measure the clearances then work out what shims you need.
If you still have no clearance with the .200 shim you will need to tip the valve stems.

If you are at 2.40 already I'd take the valves back to the shop and have the stem shortened. You want to start off with the shims in the 2.60 range or higher since the head is already apart.

I set my valves by using just the inner spring and installing one valve at a time. Just lay the cam in the saddle and measaure. I spent a lot of time doing all this and at the end of the day, once the head was installed and I double checked, I had to change every single shim to something thicker. I was surprised. Maybe I did something wrong? Or maybe you just can't properly replicate the real world configuration with the head on a workbench?

Is it a good idea to grind the valve stems on shim-on-bottom type setups? Just a couple of hours ago I learned that I'm in the same boat with the #2 intake valve on my '83 GPz 750 head. FSM says "don't grind them" because the shim may contact the spring retainers or split keepers which could cause it to drop a valve.

It depends on how much you take off.
Steve