Not coils but still not running on all 4 cylinders

[martinz1000r]

Traced the coil issue to a dodgy connection on LT side. Also sorted out leaking cam cover but have now found something more worrying.

We now have big, fat sparks on all 4 cylinders. It starts on the button but runs like a dog under load and is definitely not running on all 4 cylinders. It is also spraying oil from between barrels and head. There are no nasty noises from the engine and all was fine so it is timed up ok from an ignition and cams point of view. I don't have a compression tested so can't tell if we have a major piston rings issue.

Plugs are not oily after a run and they look reasonable from a colour point of view if perhaps a tad weak.

Any recommendations please?

[Pigford]

If its leaking oil betwix barrels/head.... could well be loss of compression thru head gasket

[Pasc]

Martin, I'd agree with Pigford.
Machine Mart do a relatively cheap compression tester. If you can't get one sharpish you are welcome to a loan of mine if it helps. Drop me a pm if you need it.

[bigmac103]

I just had exactly the same thing on my Z1B. Check compression as Mr P says. When I got it stripped down I found a loose stud and a blown head gasket where the leak was coming from, I've replaced the gasket, thread locked the stud, replaced the valve oil seals and then found stripped threads on the camshaft bolts...I've opened up a real bag of but at least I now know what's going on with the engine

[martinz1000r]

Cheers Guys. Sounds like a fun day off for me tomorrow.

Pasc - thanks for the offer - I will pop in to Swindon tomorrow and see what Machine Mart has to offer. Failing that I will take you up on your kind offer. Will PM you if needed.

Martin

[martinz1000r]

Purchased a compression tester this morning and got the following results:

Cyl No 1; 90psi, 2; 130psi, 3; 140psi, 4; 90psi.

Something defo wrong with 1 and 4. Am wondering if I did not get the rings lined up properly when I put the barrels on? Oh well, cylinder head off

[DogsbolloxofZ1B]

When you've got to the piston rings make sure 1 & 4 top & second rings are the correct way up. Standard rings have letter N stamper and this should face the sky.

Mike

[martinz1000r]

Head is off. No obvious damage to head, valves or bores.Here are a couple of pictures:



Looks like no4 cylinder has seen no sign of combustion given how clean it is.



Fuelling issue?

No 1 cylinder looks very black so could this be where oil is coming up past rings?



Barrels off next!

[martinz1000r]

and here is why it is only running on 3 under load!!!



Slide on no.4 is not lifting with the rest. Some thing's broken in there! Any Mikuni experts?

This explains why it seems to idle and start ok and runs like a dog when on road. Only get big dollops of fuel to 1,2 and 3. No4 on idle jets only.

[chrisNI]

That'll do it....

[martinz1000r]

Easy fix!

Top off the carb reveals the retaining screw sitting on top of the slide. Screwed back in ok and all lift as they should now. Just the compression and oil issues to go.

[Al]

Glad you found the problem with combustion at least.
The other issue of oil leaks; has that head been skimmed since it destroyed the number four piston?
Have you had a straight edge on it?
Did you have a one piece gasket or a two piece and what did you fill the chain tunnel 'O' ring track with?

Just fitted the 1171 (1166) kit and a unitrack head like yours and made a simple note on one of the piston kit advice slips.

It says;
Coloured = Top
Matt = Second ring.

Bit ambiguous now but i think it refers to the fact that there are two rings of the same size in that particular kit and it wasn't obvious to me which was which.
After speaking to Debbens and others that was what i wrote to myself.

If i remember; the coloured one was blood red.

I noticed that you had had a lot of problems fitting the rings from a previous thread.
Have you definitely got the expander rings ends butted as its easier to have them overlap?

With that piston kit and the bi-spherical head you should have a compression ratio in the upper 10's
Compression pressure should be in excess of 160 p.s.i. i would think.
Comp ratio on my identical setup is 11.2:1!!!!!!!!!!!
Lucky i used a couple of base gaskets.
Have the pistons been clearanced at the exhaust pockets to take account of the different exhaust valve angle on the unitrack head?



AL

[martinz1000r]

hi Al.

Head was overhauled last summer by Tim Blakemore racing in Bristol. Don't think it is skimmed but putting a steel rule across it all looks nice and flat. It was gas flowed and valves done so hoping nothing wrong with top end.

I was using a one piece Cometic head gasket and had filled the tunnel with Permatex Ultra copper gasket goo. Should I have used the O ring in this tunnel? I have a brand new one I did not use as I read on another thread on here that it is not needed with 1 piece head gasket.

I have poured a little oil in to 1 and 4 cylinders and this does not seem to flow away. Not sure how much of a test this is but as you rightly point out we had a mare getting the barrels on so any reason not to remove them again.

What I have found is that the APE studs I fitted were not as tight as I think they should be. Most of them I have been able to tighten down considerably with a couple of nuts on the threads. Would this contribute to loss of compression and oil leakage? My thinking is that this meansd the whole assembly was not torqued down as it should be despite the nuts being tight at the head.

As to heritage of engine and head it is all Unitrack so no concerns over valve angles etc as they were made to go together.

Really appreciate all the advise! Was going to get it MOT'd today but that is out the window now!!!