Rings or not

Thanks for you kind comments. I am a massive Zed head and have a thou and a niner as well, to name but a few. I thought green Kawasakis going faster was accepted science and never disputed :lol: She was black originally, but now quicker in green. :lol:

She is a Godier Genoud special built in France when she was new. She only has one shock on one side - a Koni F1. The forks have 2" slugs in making the ride height excessive, but give a bit more ground clearance; though I have still scrapped both sides out! When examining the head I can see that someone has done some porting work to the head.She was fitted with Brembo Goldline master cylinder, calipers and discs back in the day. I have replaced the calipers with Harrison Billet 6 pots and a more modern Bembo mastercylinder - the original Brembo was had too big a piston bore and gave a wooden feel. She stops like a sports bike now

I pulled the head apart last night and discovered that all the shims are pretty thin. The valves look good and the engine is pretty low mileage, so I can only assume that someone got a tad overenthusiastic when re-cutting the valve faces in the past. Two are actually minimum 2.00 and the fattest is 2.25 :roll: I shall nip 0.4 or even 0.5 off the top of the stems. I know Mr Kawasaki says only 0.3 but given how tight they are I have little choice. There's plenty of room at the top of the keepers. I'll need to change the exhaust guides as they're all sloppy, which won't help the thin shim problem :grr:

I have managed to source some NOS piston fitting tools and I think I'll try them and treat the old girl to a new set of rings, just to be on the safe side. I can get a set of genuine ones ... for a price!

My only word of caution regarding grinding the top of the shims is to check/ensure that the cam followers don't start picking up the valve spring retainers. I looked at taking more than .5mm off of the valve stems for the same reason but shyed away. If you assemble a valve with the retainer and keeps on lt and place a straight edge across the top of the stem, you'll see what happens when you take more than .5mm off of the stem and I don't think the tit in the bottom of the shim bucket will accomodate a whole lot more.
I have 4 valves needing 1.95mm shims to get .005" clearance. The valve faces have been ground but when I take measurments with new valves and compare to the ground valves the difference is only .003". So even with new valves I still need 1.95mm shims. The only resolve for you and I is to have the valve seats replaced in the cylinder head. Not a big job for a good shop but they need to be cautioned that when cutting the new seats to cut to the lower dimension as spec'd in the service manual to get you to the 2.80 - 2.90 mm shims. Then you have lots of options down the road.
I have decided to grind the cams. I'll be taking .8mm (.032") of of the base circle to get me back to 2.70- 2.80mm shims and hopefully + .025" in lift. Another trick I want to do is run with 2 intake camshafts instead of 1 intake and one exhaust. The intake cams have a higher lift than the exhaust by .5mm (.020") and I can make up the duration from 270 to 280 in the grind. Both of the cams come from the same billet and if you look at the intake cam, you can see the boss on the cam where the tach gear is cut when used for an exhaust cam. That gear is a 4 start 2.5mm pitch gear. Simple enough to cut. Anyway, I'm hogging your topic and I shouldn't be doing it. Just thought I'd throw in some things for you to think about.

Kawboy wrote: My only word of caution regarding grinding the top of the shims is to check/ensure that the cam followers don't start picking up the valve spring retainers. I looked at taking more than .5mm off of the valve stems for the same reason but shyed away. If you assemble a valve with the retainer and keeps on lt and place a straight edge across the top of the stem, you'll see what happens when you take more than .5mm off of the stem and I don't think the tit in the bottom of the shim bucket will accomodate a whole lot more.
I have 4 valves needing 1.95mm shims to get .005" clearance. The valve faces have been ground but when I take measurments with new valves and compare to the ground valves the difference is only .003". So even with new valves I still need 1.95mm shims. The only resolve for you and I is to have the valve seats replaced in the cylinder head. Not a big job for a good shop but they need to be cautioned that when cutting the new seats to cut to the lower dimension as spec'd in the service manual to get you to the 2.80 - 2.90 mm shims. Then you have lots of options down the road.
I have decided to grind the cams. I'll be taking .8mm (.032") of of the base circle to get me back to 2.70- 2.80mm shims and hopefully + .025" in lift. Another trick I want to do is run with 2 intake camshafts instead of 1 intake and one exhaust. The intake cams have a higher lift than the exhaust by .5mm (.020") and I can make up the duration from 270 to 280 in the grind. Both of the cams come from the same billet and if you look at the intake cam, you can see the boss on the cam where the tach gear is cut when used for an exhaust cam. That gear is a 4 start 2.5mm pitch gear. Simple enough to cut. Anyway, I'm hogging your topic and I shouldn't be doing it. Just thought I'd throw in some things for you to think about.

Thanks for a very interesting reply

DO Z1300s have a tendency towards this problem? I had a look online for a replacement head, but you could see from the photos of all the heads for sale that the shims were thin.

Thanks for a very interesting reply

DO Z1300s have a tendency towards this problem? I had a look online for a replacement head, but you could see from the photos of all the heads for sale that the shims were thin.

Can't say for sure. I bought a second head off of FleeBay for a "just in case" senerio. I checked it for shim requirements with new valves and found the difference between the 2 heads of only .002" . So either way, i'm grinding camshafts to fit. Good luck with you endeavors !!

Forgive me if you've explored this already but could you ......

Use an oversized valve to move the valve head down in seat (towards the piston)

Or, use an custom length valve stem (shorter)

Or, or use valves without the keepers groves pre-cut (i.e. you could make the valve any length you need)

(not sure if any of this is available in 1300 sized valves).

Custom valves are an option but Ferrea gave me a price of $60 U.S. a piece. This would be a bandaid approach. The problem is the seats are cut too deep so to bring things back to spec if you have to shell out the money, would be to have the seats replaced at or about the same price as custom valves. Otherwise, if you go with modified valves, you now have to bear that in mind when future problems come up.
I'm pretty sure I can grind my own camshafts and get back to reasonable specs. No cost to me and if I bugger up a set of camshafts, I have 5 more sets in the shop. Don't ask me why I have 5 more sets 'cause even I don't know. I think I found a few sets on Fleebay for $40/pair shipping included so I grabbed them. Besides, this is the type of "Fun" I have. Learning something new and taking the skills I have aquired over my lifetime and applying them. Then testing for results.

Ok, I'm stopping here so I don't hog the thread.