A Z900 challenge to the forum with a prize

[Phil50]

As you may have read I have a heap of a Z900. It is unfixable and has had far too much money thrown at it.
The original fault was choking in fuel and running rich could not be ridden.

It was assessed by two garages, they concluded the same fault.
Low compression and carbs knackered. don't they always say carbs knackered as a substitute for knowledge on setting them up.

Anyway I had the block rebored to 66.5mm and replaced the pistons/rings cams/shims and the head (for a Z1000A4 for the 8mm studs), which was skimmed and all bead blasted.

reassembled and the compression was still low.The carbs were broken by an idiot and a newer set purchased. The fault still remained.

I fitted an electronic ignition and two cylinders packed up. I have many people look the bike over and they all say the same. "I just don't understand it"! "It should be perfect". Anyway I stripped the head and re did the valves and got the compression up to about 100psi on three pots.

Replaced the plugs for the second time. She fired up and ran for two minutes and died from black fuel inhallation. Still rich as Rothschild.

Gave up for some weeks and ran out of money to throw at it.

Eventually I replaced every jet/bit avaliable fo the carbs and cleaned all the choke valves and slides and soaked the entire carbs overnight in industrial meths. Cleaned with petrol the next day and dried out.

The bike fired up and ran perfectly. I drove it for about a mile and back to the old runnning on three or two or whatever and limped home with black dry dusty plugs as usual.

Well I gave up and called in the "Dogs Bollocks", who VERY kindly took this thing away and for a week played with it. Re did the valves and the compression is well in spec on on the lot! It should increase a bit after runnning in as well. Excellent. He also ripped the Electronic ignition out and put the old points back, replaced a coil (suspected faulty) and set the carbs up, also raised the needle from position 3 to position 2 to lean the mixture a bit

Took it for a spin and asked me to collect it. AHHHHH I was in heaven, I willl get to ride this bike this year. I picked it up after seeing it idling wonderfully only a slight uneveness put down to, it needs a good long ride.

Next day I put brand new plugs in NJK B8ES and fired it up. On half choke for about 45 secs and then off. It was perfect. I rode it slowly for about 2 miles and parked it. After 5 mins I returned to start it up and of course it was back to square one. Running rough too rich and limped home to find dry black dusty plugs.

Last resort I cleaned the plugs and put a third set of carbs on the bike and started up to find it ran on 1 and 4 only and they are rich!

Well I ain't so I have to call it a day. My options are to break it up and sell the new bits off for what I can get and the old bits also. Try and sell it for 20% less than cost as otherwise it is in super condition. Or this option

Offer the challenge to this forum to see if anyone can make it run for 5 miles with the plugs looking normal and receive a wad of sweaty money for the trouble (offer ?100+)


I am running a Harris streeet legal pipe with 115 jets. first set of carbs were with 120 but still no better. Perhaps the bike needs a good long ride at speed, but first it has not been run in yet and has done 5 miles since engine rebuild and also it cannot get further than a mile before screwing up.
The embarresment factor is also entered into by mates who buy a 25 year old H**** goldwing left in a garage for years, replce the battery and ride it round to me for a good bloody laugh! I was considering a swap but he told me to piss off.

So I await the replies
thanks
Phil

[Thezedsintheshed]

Hi , it sounds as if you have checked or changed all the obvious possibilities which should have ruled out or cured the cause of the problem, that leaves one of two possibilities , either you have replaced an item and kept the original fault or the original fault has not been traced. The only 2 items in the system that you appear not to have changed or replaced are the air filter system and the exhaust.
I ran my Z1000a1 with a road legal Harris pipe and a standard airbox a few years back and had exactly the same running problems as you are having now. Solution was to fit a set ok K & N filters and bin the legal baffle in exchange for the race baffle and the running problems dissapeared totaly. I found that the legal baffle was causing the engine to choke up changing the baffle instantly cured the running problems and fitting the K&N's was just an addition to complete the job.
Another possibility is that the choke plunger seals in the the carbs are knackered, which in effect will cause the engine to gradually flood itself and choke up. You may have inadvertantly changed one knackered set of carbs for another set.
This might sound like an obvious solution but if there is someone with a sound running Z9 that close by that can help you out then swap over the carbs and try you bike again, if it is still the same then swap the exhaust system and try it ,if everything works ok and the fault has gone then you know that the rest of your bike is ok. Then try your old carbs again before swapping back to the legal harris , that will rule out your carbs as being faulty.
All that said I still recon the original problem is being caused by the legal baffle chokeing the whole system , so try the cheapest option first, take the baffle out and nip out for a quick blast and see how it goes.
cheers Phil

[Obr]

Have you checked the rubber inlets?

[Rich]

Are you running the original wiring harness?
Are you running the original switch gear?
Are you running the original earth lead to the battery?
Are you running the original ignition switch?

Have you checked the fuel heights of the carbs NOT the float height as the needle may not be shutting off?
Do you have rust inside the tank?
Have you fitted an inline fuel filter if so what sort?
Is the tank breather clear?
Choke seals are a good point and make sure that they are shutting properly

Harris exhausts are S***e - technical term that - especially with the street baffle in as Thezedsintheshed says chuck it in the bin

[Jeff Saunders]

I'm with some of Rich's checks.

Many of the Z's suffer from poor electrical systems.

Check the battery voltage with a fully charged battery and the ignition off - you should see a reading around 12.5 volts.

Then check the voltage at the coils - you should see around 11.5 volts, but often you'll see way less as the various connections and switches in the electrical system consume power.

There's a fairly simple relay fix to up the voltage at the coils - here's a link to one of the sites with this fix http://www.wgcarbs.com/index.php?option ... &Itemid=26

[prowlerz1]

to state the obvious phil have you changed the fuel try draining carbs and while tank is off get some fresh fuel from petrol station fill carbs with new fuel and see what happens ,, where abouts do you live ??

[Garn 1]

Phil, grasping at straws... I wonder if the crank-shaft has moved on the journels. They do weld them to avoid them moving. The crankshaft can be checked with a 17mm ground rod... It must pass thru all little ends.

Speaking more of "Doom", I have heard of a crankshaft being cracked across the bearing and it still ran! I hope it's just changing the air filter & baffel. Could be just fuel, if you haven't changed the tank!
RegardZ.

[Phil50]

I thank you chaps for these helpful suggestions.
the crank is fine. What that would have to do with rich running is beyond me?

I did get a phone call today from a mate (the Goldwing pisstaker ))) He checked with an old fellow mechanic who had an identical problem a few years back on a bike. He swapped petrol tanks and it ran! He suggested removing the tank, clean it out (it has been resprayed so may have paint inside)fit proper decent fuel filters (I have none) and test again. This could be interesting as it is hard to think three sets of carbs have the same fault. The tank is a common factor that has not been addressed yet, although I did test the air valve in it as the manual states that if faulty causes rich running.

Prowlerz1 you may be onto something here!

I am unable to source a racing baffle as Harris no longer exist and there is no way to get help from the company that took over they are not interested in Z900's. I am understanding this somewhat. Back in the day (1982) I ran a Harris 4-1 peformance pipe and simply changed the main jets from 115 to 120 and ran a standard air filter NO problems whatsover. When Summer came I put the original 4 into 4 back on and put 115's back no problem. In those days there seemd to be no faults at all and life was simple LOL, guess it must be age, there does come a time when things have to be retired and thats a fact.

I also will be testing the electrics again with an AVO as Even though i am an Electronics trained engineer I do not like nor trust these crappy Digital meters. Like all things digital they never match real analogue equipment.
So tomorrow i do battle one last time. If it fails the heap can stay under the cover till March 2008. At least I wont have to pay road tax!
thanks all
Phil

[Steve R]

Phil,
If it is the fuel tank you can get a slosh tank sealant from FRosts which coats the inside of the tank, this works well.

What you need is someone off here thats near to you to come and swap their tank and carbs first then if that does not work exhaust as well.

That way you can start eliminating parts with known good ones without it costing anything.

Where are you, there are plenty of very helpfull people on here, I am in West Yorkshire just North of Bradford if you are near to me I would be more than helpfull to come over on my z1a and do this with you.

Steve R

[Liam Crowe]

Hello Phil,

Sorry to read about your trouble with your bike, did you get any help.
I wont be able to help you - dont have enough nohow.

Regards


Liam Crowe

[DogsbolloxofZ1B]

Steve R,
Thats where I was beginiing to struggle. I had no parts to try to eliminate problem areas. If I could rely on a goood set of carbs that would eliminate one key area of concern I have.

Phil, Good luck.

[knut]

i hope you get it sorted phil,has anyone had problems with the seals in the choke circiut,sounds like it could be the cause of my troubles on my kz900 a4,i,ve number 1 & 2 running rich and 3 & 4 running lean.
the joys of owning a classic

[Phil50]

Are you running the original wiring harness?
Are you running the original switch gear?
Are you running the original earth lead to the battery?
Are you running the original ignition switch?

Have you checked the fuel heights of the carbs NOT the float height as the needle may not be shutting off?
Do you have rust inside the tank?
Have you fitted an inline fuel filter if so what sort?
Is the tank breather clear?
Choke seals are a good point and make sure that they are shutting properly

Harris exhausts are S***e - technical term that - especially with the street baffle in as Thezedsintheshed says chuck it in the bin

Thanks for the suggestions. Harris exhausts are not "shit" actually. some would say the same of Z900's. Perhaps your friend would give a scientific reason why in "his" opinion they are? I prefer to act on proven data that has been tested and evaluated rather than rumour and opinion.

Your ideas have value, and I think one in parcticular is going to fix theis bike. I will let you know whcih one it is over the weekend.
thanks for your help
regards
Phil

[Phil50]

I live near Harrow, middlesex.

[Rich]

Perhaps your friend would give a scientific reason why in "his" opinion they are?

Same bike, same dyno, harris exhaust wouldn't run right took it off and put a Neta on and made 5bhp more, but that was with the world famous street baffle.