Oily pipes, fresh Z1A

[MrDavo]

Well my running in was going well, 350 miles in a week after getting the Z1A back on the road after a long sleep as an unfinished project. The bike is running perfect (apart from a poor tickover when hot sometimes) but I think my valve oil seals are shot.

Saturday I did 100 miles running round the Peak district, I met a lot of people who have had a zed at some time in the past. When I got home, I noticed, to my horror, a load of oil in the ends of #1 and #2 pipes. Also, the oil level had dropped from Max to Min in only 100 miles, a bit steep. When I started from cold, I noticed a puff of blue smoke, but absolutely none during riding. I hoped it was due to overfilling - I had topped up to the top mark in the sight glass, however I would expect some oil in the airbox, and there was none.

Sunday I didn't top her up, I cleaned out the pipe ends with paper and brake cleaner, and went for a test ride. This was the result:



The upside is that those two pipes will never rust from the inside. I should watch for drivers behind me putting on their wash / wipe. Its also on the rim, chainguard and the back and front of the number plate.

I'm guessing that, as the engine was rebuilt an unknown time ago, that the valve oil seals have perished and failed. When I stop on a ride I use the sidestand, which probably pools oil on that side too. If it were bores or rings, I'd expect smoke and oiled plugs if it were using that much oil. the fact it's not oiling plugs makes me think specifically exhaust valve seals, the oil is going straight into the pipes without being burned.

I've seen the Suzuki Viton seals recommended on here, I'll order a set, also I need a Vesrah top end gasket set, can anyone point me at ones which have the split head gasket (typical Ebay blaggers are advertising sets with single head gaskets as fitting all 900s), if not I can get a full set from Z Power. Never had the head of one of these before, I have a shop manual, but there may be questions. I'll check the valve clearances before I take the head off, to see how accurate they were and give me a heads up if I need extra shims.

[Ultim8pc]

Sorry to hear of your woes. Could be stem seals or bores/rings.
Normally blue smoke on overrun is oilseals and white smoke all the time is the bores/rings.

As you'll need to top end off to sort either you'll be able to figure it out either way.

[MrDavo]

The puff of blue smoke on startup makes me think its exhaust valve seals. My 911 does that, I'm sure for the same reason, but they are 36 year old seals, as far as I know.

I was told that the engine was rebuilt by someone who was ‘ex BSB’ but he could have made the tea for all I know. How long ago is anyone’s guess, although imported and UK registered in 1995 it hasn’t come up as on the road since Swansea started publishing records, not sure which year that started.

Anyway when I get in there (I was tempted to whip the head off before putting the engine in last year, but took a calculated risk) I should know if it’s right or not.

A pair of topless photos I took last night. Nothing much to report other than all very clean with no signs of scuffing on the cams.

[MrDavo]

One of these things is not like the other....



I'm not sure if I should be worrying about the two pistons with NO carbon, or the two that have coked up that much in only 375 miles. Either way its not right, I'm glad I pulled the head off, I'm sure it wouldn't have lived a long and happy life like that. As far as I can tell I didn't have an air leak from the inlets, everything was tight, the rubbers are new. The plugs were pretty much like the pistons, pale and weak looking on #2 and #4, sooty on the other two.





Until I borrow some calipers, I can't accurately measure the bore to piston clearances. The piston thrust faces are lightly polished, as are the honing marks in the bores.

I'm wondering about the head gaskets. I had been intending to retorque the heads at 500 miles when I did a service, but when I took the head off I was surprised how untight the head nuts were, it didn't take much force to undo them. could the gasket have 'settled'? could oil and/or air have been getting into the bores around the gasket? That could explain both the air and oil where it shouldn't be? Air could get into the 'clean' cylinders (there was a whistle but I assumed it to be induction noise from the airbox), and or oil from the feed studs into the bores. Or it could just be the valve seals, which seemed to be hard and not a great fit around the valves, which had black burned oil deposits on them (they were new).

By the way, Saturdays test ride has produced my first Notice of intended Prosecution for speeding in many years. I saw the van, but too late, it must have been set to long distance looking down the hill I was coming up. At 42mph in a (deserted) 30mph limit, I just qualify for a Speed Awareness course, I looked up the limit and it is up to and including 42mph. Hopefully, it is up to plod's discretion.

[zed1015]

2 and 4 look washed with oil and are the likely to be the worst culprits of the oil in the pipes.
The other two are at least getting to burn some of it.
It seems to be a lot of oil for just stem seals so i'd be looking at the rings too.
What do the plugs look like.

[MrDavo]

The plugs look just like the pistons - dark and sooty on #1 and #3, light and weak on #2 and #4.

The rings look to be in order, no gaps lined up, and no sticking or damage visible. I wonder if there may be head gasket issues, as I said It didn't take much torque at all to get the head nuts loose. I checked the head with a straight edge, it doesn't appear to be warped, thank heavens.

As one pot on each side seems to be running on excess oil, its odd that it only came out of #1 and #2 pipes, which are linked to each other. I've had a lot of cars and bikes in bits over the years, never seen this before.

[chrisu]

Check the oil scraper ring is set up correctly . I.e butted up ends not overlapping slightly.

I’ve seen them not and it made the bike smoke

Typically found straight after a rebuild....

[MrDavo]

I'll check that, Chris, thanks.

I may have found the smoking gun. The head gaskets weren't cleaned or wiped when I took the head off, they went straight into the parts tray.

First photo is the left side, you can see oil going from the stud, top right in the photo, across the gasket (and under the head) to #2 cylinder (the lower one )



This photo you can see a similar trail, from the front right stud to cylinder #4.



2 and 4 are my two 'wet' cylinders.

Am I right in thinking that the oil feed to the exhaust cam comes up the front outer studs? There don't seem to be O rings to stop it leaking in the parts book, and oil flow diagrams I have found are vague about the route up to the top end taken by the oil.

[zed1015]

The oil feed comes up from main gallery at the rear of the block and up the two outer REAR studs BUT it is linked to the front outers via horizontal drillings in the head to the exhaust cams.

[MrDavo]

I'm going to bite the bullet and buy Kawasaki genuine head gaskets, the ones in my generic gasket set are no better than the ones I've taken out.

The real thing costs an arm and a leg (£151 pre discount and P&P) for the pair, however when I did my CB750 I paid over £110 for a real head gasket, because they work every time.

I'll never know for sure, but maybe I could have got away with just retorquing the head rather than pull it all to bits. I would still have been on knockoff gaskets and valve seals though, if I use the best I know I've done the best job I can. The Viton valve seals showed up this morning.

[Ultim8pc]

I'm going to bite the bullet and buy Kawasaki genuine head gaskets, the ones in my generic gasket set are no better than the ones I've taken out.
The real thing costs an arm and a leg (£151 pre discount and P&P) for the pair, however when I did my CB750 I paid over £110 for a real head gasket, because they work every time.
I'll never know for sure, but maybe I could have got away with just retorquing the head rather than pull it all to bits. I would still have been on knockoff gaskets and valve seals though, if I use the best I know I've done the best job I can. The Viton valve seals showed up this morning.

I'd always use genuine head and base gasket, I've had too much trouble via copies.

[Philippe]

Hi men

I never wait 500 miles before a retorque of the cylinderhead nuts. As soon as the engine has been running for 10 minutes and got warm I let it cool down an the next day I do a retorque. After a few hundred miles I do a retorque again. Never had any problems.
GrtZ
Philippe

[MrDavo]

I’m away next week, but when I get back I’m taking the barrels and pistons to an engineering shop I’ve had recommended to me, to accurately measure the clearances.

With the cost of genuine gaskets, I’m damned if I’m going to put it back together for a few oily miles, then rip it apart again. Do it properly, do it once.

[MrDavo]

I just got back from Stockport, where I have dropped the barrels and pistons off at Quasar Engineering, which come recommended by my mate in the classic bike trade.

I included a sheet saying what (and why) I need measuring, plus a copy of the page from the workshop manual dealing with piston clearances. If the measurements show that the rebore was cocked up, then +1.0mm pistons are avaiable, though I don't want to use up the rebores if I don't have to.

While I wait I need to sort the head out, here I have fitted the Viton valve seals, using the wheelie bin again as an outdoor workbench.



For the sake of my sanity and valve clearances I had been warned that under no circumstances should I get shims and valves etc mixed up. A root around revealed a tray (with lid) for dips, nuts etc that we inherited from my Mother in Law. Once at the centre of the dinner table, with its 8 compartments it turned out to be just what I needed!

[kev edwards]

You cannot beat those rolling work benches provided by the local council can you.