Z1OwnersClub GB

Right where do I start, ah yes, desided the Z1000a1 needed to be tarted up a bit and usual story, ended in a full resto. Anyway engine given the full treatment of welded balanced crank with a nice new set of Wiseco 1075 high compression pistons, Dyna S ignition amd Dyna coils with Taylor leads
Anyway seeing as the wallet had been totally emptied I thought I better take the sensible route and run in the engine which I completed up to 500 miles without any problems and it running as sweet as a nut. Right decided it was about time to open it up a bit but got a little carried away!
At about 9500rpm there was a horrible mis-fire and banging noise. Glided to the hard shoulder and then had to push the bloody thing 2 miles.
Got it home and checked the compression - good - checked the valve clearances - good - checked ignition timing - good - checked the quality of the spark - not that good so checked through all the associated wiring / connections - good - replaced spark plugs with new - started to a fashion so took it for a spin - not bad but not good either. Kept checking and fettling to get it to run better which it did so took it down the road again for a test - ran lumpy up to 5000rpm then cleaned out a bit so I carried on at a fair old lick with everything hunky dorry untill it just died again on the bloody motorway!!! Pushed it home agian!!! Put it in the back of the garage so I couldn't see it for a while whilst I cooled off!
Got it on the ramp today and thought I'm going to have to remove the head and barrels to see what is going on - initially looked ok but then I've noticed that the bores seem to have some areas that have obviously had the pistons rubbing against and that the pistons (all four) have wear/scratches on the skirts after only 500 miles!
Now I know what your saying (what a w****r) but is this going to mean a new set of pistons and the next size rings or could I possibly continue with these if not too bad!
I'm so skint at the moment that I've considered spray painting the kids black and offering them to Madonna to raise some cash, problem is Mrs S says she has grown quite fond of them.
Help desperately sought!!!

Sorry even the photo's are crap!

wish i could give you some answers there Mark, im siht with engnes. sorry to see youve had a bad return on the rebuild, im sure some answers will arrive soon.

Eyup!
This might sound stupid but 1075 pistons dont fit in 1015 bores. You dont say whether or not you rebored but it sounds like the pistons are not fitting quite right in the bores. If they are too tight you will suffer from partial siezures and scoring. As you have the motor down I'de be checking this. Good luck.

Hi when you rebuilt the motor did you have the bores honed with a light crosshatch?

Rebore was completed by Deben's and prior to build up I checked the piston clearance and ring gaps and they were all fine. The engine started first press of the button and ran perfectly for the first 500 miles however I didn't push the engine within that 500 miles although a lot of the milage was done two up. Just can't beleive that opening it up twice has done this amount of damage. Obviously I am going to need to know what the cause is as well so that when it is finally rebuilt it doesn't happen again. The plugs and piston crowns are really black and sooty.

Paul

we must have posted at the same time.

Yes the bores were honed and it is this honing that has been removed in some places on the bores.

Hard to see the scuffing in the pic's but it's not uncommon and i'm pretty sure you won't need new pistons ok. Get the bore clearance checked. If too tight you might be suffering cold seizures. so get them honed to the correct clearance and fit new rings. If the rest of the motor is good there is the possibility of fuel starvation which will give the same symptoms. I would say the ignition too but it's unlikely with the dyna stuff fitted.

Excessively rich mixture will wash the bore's which can cause lube and overheating problems leading to abnormal wear and scuffing. Can't see debbens getting it wrong though.

Obviously as you can see Photography is not my forte either.

Think I might have to go and see the boy's at Debben's and see what they think. The carbs are standard but I did increase the main jet size and drop the circlip down on the needle by one notch so your theory could be correct.

What size main jets are you using. On my wakisaki z1r i'm running 1075 wiseco's ,gasflowed head, jim wells cams,k&N filters,4-1 pipe. and carb is set up with 125 mains ,circlip in std position. Been like that six years now. Sounds like you should have 117.5's in or there abouts.

A bit of scuffing on the piston skirts can be polished out..... Did you "gap" the rings OK?

Running in for 500 miles sound OK to me.... as long as it was 'run in' OK... varying light throttle load/revs...

Is oil pump & screen OK Re check ignition timing & advance unit too

What pipe & air filter set up? If 4:1 & K&N's... Id have thought at least 120 mains Each motor is different though.

Can't remember the exact sizes as it was quite a long time ago now and I'm getting old so seem to forget things at the drop of a hat. It wolud appear from the responses that the overall engine build was okay it's just that I've fu**ed up finer points of the carburation.
The carbs are sat awaiting to be stripped so I'll make that my next job. The carbs are the standard 26mm items with K&N filter in the standard air box. The exhaust is a custom made 4 into 2 complete with balance pipe however there pretty much unrestricted baffles (sounds fantastic).
When it is back together I think I'm going to have to find a Dyno to see what is happening and to complete the finer tuning.
Don't think i'm going to be ready for the Ace though!!!!!!!!

Was assuming you had std pipe and air box with just the wiseco's but with the free'er pipe and K&N then you are looking at around the 120's.

i used to run my z1b on 122 jet ,middle slot on needle,k/n air filters ,and an harris.couldnt run any better.

Need better photos