Smokin!!!

[Russ]

Just like to say Hi to everyone before I pick yer brains. I'm running a Z1000 A2 fitted with a 903 Z1 engine thats been bored to 70 mm fitted with hicompression pistons and fast cams. I'VE JUST COMPLETED A TOP END JOB TO REPLACE BADLY WORN CAM CHAIN GEAR INCLUDING THE INTERNAL ADJUSTER FRONT GUIDE AND BOTTOM ROLLER. WHILE THE BARRELS WERE OFF I NOTICED THAT ALL FOUR TOP COMPRESSION RINGS WERE BROKEN NEATLY IN HALF (PROBABLY DURING THE LAST FITTING I SURMISED) SO I REPLACED ALL THE RINGS FOR NEW. I REBUILT THE ENGINE WITH NEW GASKETS AND VALVE STEM SEALS. THE ENGINE HASN'T DONE MANY MILES SINCE THE BULK OF THE WORK WAS DONE(NOT BY ME) SO BORES LOOKED GOOD SHOWING LITTLE WEAR AND SURPRISINGLY LITTLE SCORING SO I DETERMINED THEY WERE OK TO USE. RING GAPS WERE WELL ON SPEC TOO. THE PROBLEM IS IT SMOKES LIKE A RED ARROW LEAVING A SCREEN THATS EMBARRASING BEHIND ME DOWN THE ROAD. THE BIKE ITSELF GOES EXTREMELY WELL JUST SMOKY. I'VE HAD THE HEAD OFF THREE TIMES NOW AND HAVE DETERMINED THAT OIL IS GETTING INTO THE BARRELS BY SQUEEZING PAST THE HEAD GASKET ITS ALSO NOW STARTED TO SHOW AROUND THE EDGES OF THE JOINT ON THE OUTSIDE. LIKE I SAID THE GASKETS WERE NEW BUT I HAVE SINCE PUT THE OLD ONES BACK IN AND THEY HAVE IMPROVED THE SITUATION A LITTLE. IS THERE ANY WAY THE OIL PRESSURE COULD BE TOO GREAT. JUDGING BY THE LIGHT PRESSURE IS GREAT ONE KICK AND ITS OFF. BREATHERS ARE FINE . ANY IDEAS?

[Jerry]

When does it smoke? Under power tends to be a piston/ring problem. On the over-run or when pulling away after ticking over for a while points towards valve stem seals. Whatever you do, carry out as many checks as you can before you strip the motor, to try and save spending money you don't need to!

[Rich]

When are you re-torquing the head?

Did you hone the bore?

How are / did you run in?

Did you overlap the oil control ring?

[Pigford]

Zeds only run at no more than 3 psi when up to temp, so very low pressure systems.
If leaking through head gasket, head may be warped?
You really need to hone the bores if new rings fitted. Do a search for the pro's & cons of running in, there's some great advice/ideas relating to this subject, somewhere on the site

[Russ]

Smokes all the time from the word go. Obviously more when you open the throttle but seems to lessen on overrun. The rings were all set up right when they went in the compressors didn't hone the bores but still can't see how so much oil could get by. If it is a ring fit problem how long do they need to bed in. Thank for all your efforts.

[Rich]

You need to hone the bores to get the rings to bed in correctly.
Give SEP Kegworth a ring and ask about glaze busting oil or take the barrels off and hone the bores.

[Jerry]

I'm with Rich - especially if you are running Wisecos, for some reason they are really sensitive to bore surface, and will pass loads of oil, even though a compression test will appear ok - same thing happened to Glenn Dixons Z1B - Classic Bike end of last year.

[chrisNI]

I asked a question that could be linked to this about a month ago - no-one commented. See here

[big green bus]

i had a very similar problem on a gpz1100 a few months ago (remember padders) it cost a load in gasket sets, smoked like a 2 stroke from the word go. in the end it turned out to be piston ring pumping from worn piston ring grooves (not the rings) i ended up getting barrels and pistons to sort it, but as most sets are getting on a bit i would now only fit a wiseco piston kit then i know what i am getting

[hanskloss]

just a thought, might be worth checking the oil pressure, if too high possibly the oil passages are clogged by silicone or other sealant bit somewhere creating excessive pressure but not pumping enough oil where it should resulting in mentioned leak?

[Rich]

Chris - just rebuilt my lump, wiseco 1075 no smoke at all. Cheap oil dumped after twenty miles along with filter. I have only taken her up to 7K at the moment though (90 miles run in now)

[davy thomson]

Wurth do a type of flushing additive that clears all the crap from your motor, you just add it to you existng oil and run the motor for a few minutes then drain. though i think you should have honed the bores as most of the lads have said.

[DogsbolloxofZ1B]

Do you know anyone with a 'lead-down' tester? If you can lay your hands on one it will give you a very good reading on the condition of your engine. Sounds like you may need to re-cross hone those bores..

[chrisNI]

just rebuilt my lump, wiseco 1075 no smoke at all. Cheap oil dumped after twenty miles along with filter.

Good news...

[Russ]

Thanks guys for all your tips. It still seems like the oil is entering the bores from the top end though. I just spent seven hundred quid and more this winter doing this and being a poor ole Z owner can't stretch to new bores.
I'll get there somehow, let you know wot happens.