No valve clearance!

Sweet, thanks jay. honestly I had no idea that this shop had no previous experience with motercyle heads, I did not know enough to ask and was probably to shy to:laugh: . Well I will just have to take it as a learning experience, you can bet the next time i want to do a vavle job I will make sure it is done right:woohoo: !!

I have a nice set of used valves and keepers that have never been ground and seated very well. I'll give those to you for the shipping. I recently pulled my 1976 KZ900 down to clean the heads, change what I was told to be the worse valve guides ever used in a gasoline engine. I had the bowls lightly cleaned up, a Serdi valve job done, I purchased new Kibble White Diamond valves, keepers, and seals plus had my pistons Swain coated, and new rings for the reassembly. The cylinders still had the cross-hatch pattern in them and absolulte 0 (zero) wear. The rings glazed over and the engine never broke-in so that's where the 125 psi on #2 and #3 came from. - not wear.

Here is a chart of the valve heights you should have - straight from the factory manual.

Regards,
Gordon

Sorry, the board won't let me attach pdf files. I can email the charts if you'll PM an address.

Ilbikes wrote:

The cylinders still had the cross-hatch pattern in them and absolulte 0 (zero) wear. The rings glazed over and the engine never broke-in so that's where the 125 psi on #2 and #3 came from. - not wear.

How wierd. I just rebuilt mine with a bore and new pistons and the compression was back up to the stock 160 psi after I ran it about 15 minutes of city riding. I guess it broke in really quick....:laugh:

Sorry, I just noticed your avitar - yours is a KZ750. My KZ900 valves won't be of any use.

Break-in of rings requires full pressure to force the rings out against the walls. This engine had 17,895 on it when I bought it recently and had never sealed the rings - never would. If you take it too easy in the first several hundred, the rings lose their sharp edges (called glazing) and will not seal in the cylinder. New rings and ball honing is the easy solution - then proper break-in.

I have never had problems breaking one in either. Every heat cycle should get a full throttle load for a few seconds, then relax, load, relax. The cylinder pressure forces the rings out against the bore and they break-in (wear-in) like they are designed to.

These are 18,000 mile stock bores and untouched photos -

Gordon

Thanks for the offer Ibikes! And that is some great advice on how to break in new rings, I am getting my cylinders de-glazed and new rings installed while i wait for my new shims. I love this forum!

I had a problem like that, the machine shop forgot to grind one valve (it was a replacement for a bent valve).


Take the shims out, measure the depth of the shim "seat", then put the buckets back on, get a feeler gauge under there...(hope for some clearance) do some math and you will find out what needs to come off of the valves.

it can be done with a dremel (at least my guy told me he does it in that way often.... ) but I had him pull the valve and grind it proper, just for jits and shiggles.

A dremel to grind a valve stem? I can't imagine it...Unless you saw him grind it then how do you know he did yours properly ?

I'd like to know how you can grind the tip of a valve stem flat and square with the stem, grinding it by hand with a Dremel.

I can maybe see building a couple of fixtures to do it, one holding the valve and another holding the Dremel, but not by hand.