Bollo**s I think I've done it now!!!!

[Pigford]

Lots of red gunk around the studs.... The oil ways weren't blocked with that stuff, were they

[Mark Stratton]

No the red gunk was as suggested by Debbens and it was only put around the non oilway studs. Don't ask me why but they seem to know their stuff so I don't question it.
Had the float bowls off and it looks like the main jets are 115's so judging by what the rest of you guys seem to be running on it would appear to be a lean mixture that is the cause of my woes.
I'm still not 100% sure about the quality of the sparks that i was getting at the time so it could be a bit of both. I've read that most people say that the Dyna coils and S ignition "will light up a bucket of piss" but I can't say that I was overly impressed. One question I haven't asked yet that is still biting at me is that the Taylor leads when measured from cap to coil on resistance seem to have an abnormally high resistance. It only bothers me because I'm a lift engineer so electricity is my game and normally a high resistance in a cable would spell trouble. So what should the resistance be of a HT lead?

[Pigford]

Double check you are getting a GOOD +12v to the coils....

I now use DYNA leads to finish off the set, but never had any trouble with Taylor before Sorry but don't know what you'd be looking at for leads

[Mark Stratton]

This is what I can't understand! Had a good 12.6 volts at the coils so was expecting a good spark. Only getting the same as standard coils. Made sure that the terminals were protected from earthing on the mounting screws and all that but still not got Blackpool illuminations.

[Pigford]

Mark, you say same as STD coils... how do you quantify this...

Have you checked max air gap it jumps, or some other method

[Mark Stratton]

To do a comparison I fitted the standard coils back on and looked at the spark it produced. Basically the spark was the same if not slightly better. Possibly I was expecting something really special on the Dyna coils. Having never used them before on any of my bikes did not really know what to expect however from what I ahve read on this forum they should be big fat juicy sparks.

[Pigford]

Mark, all due respect, but a visual check probably ain't the best for a 100% confirmation mate The telling bit is when under compression & the spark is struggling to do its job.

Keep us posted on how you get on though

[Al]

Was the top end sitting for a while (years) before you ran it up?

If you have a macro button on the camera, use that for close ups. Mine is a symbol of a tulip (flower)

Reading above i think zed 1015 hit the nail on the head with bore washing.

My guess is that it has a missfire caused by the weak spark breaking down under load specially as you say you have hi-comp pistons.

The mixture is weak at the top end which has caused partial seizures but the pistons indicate a very very rich mixture.

It's not really a mixture issue as such in the low range. More like an 8 stroke scenario under load in the higher rev range.

The rich nature of the mixture is a direct result of the missed spark (as opposed to lost spark) and the loosely attached but still pliable carbon build up created by the missfire finds it way to the rings and piston skirts under compression conditions increasingly as the revs increase and the mixture weakens, causing fretting of the rings and scoring of the skirts.
Small pieces of carbon hold the rings away from the bore and allow fuel air mixture to wash away the oil which causes overheating, friction-wear-marks and ultimately piston and ring failure.

The 'running in' is better done at higher revs in my opinion under less load. And after only 500 miles is still not ready to accept full chocolates in perhaps the way you describe.

What type of oil was in it for the running in?
Mineral or synthetic?

Are the marks in the bores where the pistons have been rubbing fore and aft or left and right?

Has there been blow by on the pistons at the locations of the ring end gaps?

Are you using premium or super un-leaded and are you running the full range of ignition advance that is set out in the original manual?

Try these guys when you get it back together;
http://www.dynojet.co.uk/tuningcentres. ... #hampshire

I use the one in Bramley near Basingstoke and they seem very helpful and knowledgeable.

Hope this helps


AL

[Mark Stratton]

Al

I'm going to try to get some better photo's tonight but basically the wear on the bores/pistons is on the for and aft not on the sides.
As previously noted the piston crowns and valves/head are very blackened by carbon.
For some reason my 75mm micrometer has disappeared (probably lent it out and it has not been returned yet!) so I can't check the pistons as yet however the bores do seem to be the same all the way round and through different points within the bores when checked with bore gauges.

Pigford

I can appreciate what your saying but how else do you test the strength of the spark. I'm not a complete idiot (well I think not anyway) but this is starting to get rather technical. Currently I'm at a loss what the next step is as my funds and severly limited. I've had to sell my Z750 project to fund the cost of replacement gaskets etc just to remove the head and barrels and see what is going on. At this rate the ZX10 nail will have to go as well.

I really appreciate all the input and help that I'm getting at the moment

[Mark Stratton]

Right these photo's are better! well sort of!!!
[img][img]http://i727.photobucket.com/albums/ww272/MarkStratton/IMG_2975.jpg[/img]
[/img]
Just popped a piston down the bore to check on clearance - the best was 0.015mm on the sides and nothing on the fore and aft.
Ring gaps were 0.403mm.

Don't look good does it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Pigford]

The pistons will clean up OK......

The Barrels can be honed & don't look that bad in photo's.... BUT...

Can you feel the scoring or is it mainly visual

Ring gaps sounds OK

[Mark Stratton]

Luckily the scoring seems to be visual so what I might do is pack it all in the tank bag and go to Debbens on Saturday morning to see if they can hone them back to life.

How would you clean the pistons? Autosolve and a bit of the old elbow grease or buff lightly with polishing mop. The last thing I want to do is cock it up even more!

Cheers

Mark

[debben1]

Hello Mark, just read your post. Those crowns are very coked up for 500 miles and there does seem to be some bore wash there, so I would suggest the fueling is too rich i am guessing you have not cleaned the airfilter in petrol or anything like that. There seems very little signs of excessive heat from the images so the poor running and cutting out sounds more like ignition, check the lead from the Dyna S to the coils, has it melted on the exhaust, come loose at the coil connection, have the coil terminals come loose ? check the terminal screws arent arcing acros to the coil mount, also check the ignition back plate does not hae any white paste oozing out from the modules, this is a sign that over 14 volts has got to the modules in which case you will need to check the rectifier /regulator. Not sure what the red gunk on studs is, we recomend a high temp rtv sealant in place of the cam chain tunnel O ring but nothing is necessary on the studs. If you want to call me I will be back in the office Wednesday and will be happy to talk you through some tests you can carry out, Regards, Steve

[Mark Stratton]

Thanks Steve, I will call you later in the week. Will you be in on Saturday morning?

Cheers

Mark

[RALPHARAMA]

The sooty plugs may be giving a false diagnosis. If your needle is a bit high you may be running a bit rich on smaller throttle openings, but when you're giving her beans, you're then running on the main jets which do seem rather small to me, especially considering the free breathing exhaust. If you're running weak at the higher throttle openings you will over heat the engine and the aluminium piston will expand more than the ferrous liner and so you are in the same situation as the proverbial choir boys arse with an over heating priest. Does it no good I would drop the exhaust valves out as well to have a looksy, as they can be damaged by excessively lean running. Prolly as well to let Debbens take a look, they certainly know their stuff.

Would yer missus not consider leasing the little ones to Madonna for a while. I'm sure you'd get a good rent and the saving in feeding costs will have yer engine rebuilt in no time

Best of luck. When you have it rebuilt I would defo stick it on a dyno, they don't charge much for bikes like ours.