Z1B Cylinder Head

[kawasaki_man]

I'm in the process of trying to reduce the oil consumption and smoke produced on my Z1B. Before starting the disassembly I check cylinder compression and all seemed well within spec. I've now removed the head and it appears that the engine problem is very likely to be due to excess oil running down the valve stems. My question concerns the valve guides. Do they play a part in restricting oil flow into the cylinder, or are they merely a guide for the valve to run in? The oil seals on the top of the valves guides were all new (emgo) and still seem fine. There is definitely some play between valve stem and the guides in most of the valves.

Question#2
I noticed previously and now that there is a slight bright spot on the cut out for the inlet valve on EACH of the 4 pistons. Is this normal? I've attached a photo of one of the pistons. There is no damage to the inlet valves but they must be running very close to pistons. (all valve clearances were correct.)

[z1bman]

no the valve guides do not restrict the oil flow.
it looks like your valves have been hitting the piston crown possibly valve timing out or wrong pistons/ valves fitted

[zed1015]

Looks like the cam timing was out by a tooth or two.
As mentioned above, guides are only there for the valves.
Those EMGO seals aren't the best so use APE or some Viton ones when it goes back together.

[chrisu]

If the wobble is noticeable I'd redo the guides

[PAULJAC47]

Been down this path b4 only use gen Kawa valve seals all the rest are a waste of time and effort,should be no lateral movement in valve guides to speak of,if your are sure your shim clearance are correct? what are they set to? standard pistons,valves? as others have said valve timing,not using one of them cheap nasty thin head gaskets by any chance?...Paul J

[kawasaki_man]

Thanks for all the advice/help...Pistons are standard size and ART, cams would seem original, inlet lift around 36.33mm and valve clearance was 0.10mm on all inlet valves. All valves are new.

zed1015 mentioned valve timing, that made me realise that the cam guide sprocket mounting bolts were not all correctly installed tightened, ie there was some movement in the sprocket if you tried to twist or rock it. This would in theory allow a small rotation of one of the camshafts and valve timing to be very slightly out.

Another way that the valve could be too close to the piston would be if the valve was actually seated too low in the head, ie if some repairs had been done to the valve seat previously. I was under the impression that the valve seat was cut directly into the head? However I then took a closer look at the valve seat and it is clear to see that the valve seat is a separate ring shrunk into the cylinder head and then machined. Is this correct? (photo attached)

Also what is the minimum clearance between inlet valve and piston meant to be?

[zed1015]

Thanks for all the advice/help...Pistons are standard size and ART, cams would seem original, inlet lift around 36.33mm and valve clearance was 0.10mm on all inlet valves. All valves are new.

zed1015 mentioned valve timing, that made me realise that the cam guide sprocket mounting bolts were not all correctly installed tightened, ie there was some movement in the sprocket if you tried to twist or rock it. This would in theory allow a small rotation of one of the camshafts and valve timing to be very slightly out.

Another way that the valve could be too close to the piston would be if the valve was actually seated too low in the head, ie if some repairs had been done to the valve seat previously. I was under the impression that the valve seat was cut directly into the head? However I then took a closer look at the valve seat and it is clear to see that the valve seat is a separate ring shrunk into the cylinder head and then machined. Is this correct? (photo attached)

Also what is the minimum clearance between inlet valve and piston meant to be?

Inlet valve lift is around 8.6mm.

Definatley wrong cam timing to cause contact with std cams and pistons.

You would need to be a tooth or more out for valve /piston contact, there's not enough slack in the std holes to allow that much movement unless they have been slotted.

Your valve seats look pretty good and ARE seperate rings pressed into the head as std, although it looks as if your exhaust valve hasn't been seating properly judging by the amount of carbon on the seat.

[kawasaki_man]

Thanks zed1015 for info about valve seat being correct. I totally agree with your comments about valve timing being the most likely cause of the problem, however I can say that I studied this very carefully when I first disassembled the engine in Nov 2011. When I bought the bike in Nov 2011 I decided to strip the engine since it had not run for 10 years and was in a real mess. I noticed the piston/valve problem back in Nov 2011 and even went to the extent to buy a NOS exhaust sprocket so that I could be sure where the mark should be.

According to the Kawasaki Shop manual I have it shows that there should be 28 pins (to marker on inlet sprocket) after the pin that sits on the marker on exhaust sprocket. Attached is the original photo from Nov 2011 that would seem to show this being correct.


This is the setup as found in Nov 2011.


I've also attached a photo from the Nov 2011 disassembly that has the same marks on the piston crown from inlet valves. This appears identical to the current situation. (The previous owner would have done the timing at least 10 years previously.)

Piston crown during Nov 2011 disassembly.


As far as I can tell the inlet valves are not quite touching the piston because there are no marks on them, only a lack of carbon build up in the "close contact" area of the valves.

Attached is picture of inlet valve from current June 2013 disassembly.


As far as I can tell the timing has been set up correctly both times yet inlet valve to piston clearance is negligible.

I've just checked my notes with regards to the inlet camshaft dimensions and it shows the inlet bearing to be 24.47mm and cam height to be 36.33mm, thus giving a lift of 11.86mm. The bearing size and cam height seem to be correct according to the Z1 shop manual.

Any comments / suggestions more than welcome.

[zed1015]

Sounds like the cam timing was correct as long as it wasn't a tooth out on the crank.

However 11.86mm lift is race cam territory so i think you have measured the wrong parts as the inlet (cam) bearing has nothing to do with it..

To measure valve lift you need to subtract the cam base circle measurement from the overall cam height and you should end up with a figure around 8.6mm.

If by some chance you do have extreme cams fitted they need to be degreed in on slotted sprockets as just fitting them with std sprockets could put the timing anywhere and cause valve to piston contact issues.

[ZedHead]

Valve timing looks spot on at the cam sprockets assuming 1 & 4 TDC position

[kawasaki_man]

Thanks for the patience shown in dealing with these issues, but I'm now much more confident that the problem must have been caused by not having the cam chain tight enough during camshaft reinstallation and the end result being crank slightly out of position. I'll never know for sure. I guess the easiest way to check after refitting the cam shafts is to rotate the engine and double check that the crank TDC mark still coincides with the camshaft timing marks. If not then timing must be out.

By the way, thanks zed1015 for putting me right on the cam lift, my silly mistake, I just assumed base and bearing were the same diameter, but a quick look shows this to be incorrect. I've now recalculated the lift and it comes in slightly less than your figure, mine is around 8.14mm.

Just one more question, what would be largest valve clearance you would be prepared to run so that the shim can't pop out of place?

[z1bman]

on the subject of valve timing there is a cut out in the end of each cam. when the cams are in the correct positions + crank is set to TDC 1&4 half of the cut out should be below the cylinder/ rocker cover mating surface

[ZedHead]

Service limit is 0.1mm. I have seen some people open it to 0.15mm with no problems except a bit of noise.

[skibs]

looks like a lot of oil passin through.surely worth checking the rings & deglaze bores while your down that far.
just to add to others suggestions,has the head been skimmed?(maybe a little to much)had same thing on gsx motor many yrs ago.extra clearance was gained by fitting 2 base gaskets.
once motor is built & timed correctly,rotate till inlet valve is fully open.push down on the valve(be carefull).you will feel the valve touch the piston.the amount of movement is your clearance(obviously)

[zed1015]

I always set my clearances as close to 0.15mm as possible.
Even as wide as 0.18 on race motors.
Always rotate the engine slowly a few times by hand ( With the plugs out ) then back to TDC to double check everything is in order and the timing marks still align.