After blowing a the head gasket on my zx9r engine BEC, I have replaced the gasket and replaced the head (easier and quicker than getting the old one skimmed).

But now I cannot get the 4th cylinder to fire,

I am getting a spark,
I have done the shims
The compression looks the same across all the cylinders and
I have given the carb an overhaul and replaced the need float valve

But I cannot get the engine to fire up on 4 cylinders.

Anyone had anything similar, any ideas as to what to check next before I take a 4x2 to the car and do a Basil Fawlty.

Cheers
Craig

Are the HT leads correct? Sounds obvious but I have fallen into this simple trap

When three, is the 4th plug wet?
Swap plugs around, swap HT leads around and see if the problem follows these.

Regards Mark

quote:

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Originally posted by mark chandler
Are the HT leads correct? Sounds obvious but I have fallen into this simple trap

When three, is the 4th plug wet?
Swap plugs around, swap HT leads around and see if the problem follows these.

Regards Mark

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Try putting a little bit of fuel direct through no 4 carb .

quote:

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Originally posted by ian locostzx9rc2
Try putting a little bit of fuel direct through no 4 carb .

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Just pour a bit down the carb only a little if it runs then it's a carb issue

Get it running then dribble a cap full of fuel into the mouth of the dead carb, if it picks up then you have a blocked jet or similar.

Could use a spray can of easy start on fourth pot to give it a kick if you don't fancy pouring fuel in.

Thanks gents, will try dribbling a little fuel in when it is running on 3 and will let you know what happens.
cheers
Craig

Doesn't No4 fire at all? Even at WOT or anything in between?

Thanks Gents, I poured a little petrol into the 4th carb when it was running and it fired up, so looks like I need to the give the carbs another good going over.

what fun.

Cheers
Craig

Any air-leaks on that pot? If it's sucking air, it may be too lean to fire or not slurping any fuel at all.

Owelly,

when you say air leaks, could you elaborate?

Cheers
Craig

quote:

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Originally posted by aka Keith
Owelly,

when you say air leaks, could you elaborate?

Cheers
Craig

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Ahhh I had checked them all, previously (ie just last week, but will check again).
Cheers
Craig

If you link the vac outlets on carbs 1&4 and 2&3 together the engine will run smoother at low revs, plus it makes it easier to balance if the tubing is already connected

quote:

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Originally posted by 40inches
If you link the vac outlets on carbs 1&4 and 2&3 together the engine will run smoother at low revs, plus it makes it easier to balance if the tubing is already connected

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stumped yet again.....

replaced the hoses on the carb vacuum take offs, took the 4th carb to bits, soaked the pilot jet and idle screw adjuster, and main jet, blasted the body and parts in carb cleaner and checked the float heights

put it all back together and still it will not run.

what is left?

Open the float bowl drain on the number 4 carb to check that it's getting fuel.

quote:

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Originally posted by dave_424
Open the float bowl drain on the number 4 carb to check that it's getting fuel.

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Then I would have thought either a jet/fuel passage is blocked not allowing fuel out, or there is a split or leak in the carb rubber that isn't allowing enough air velocity through the carb to draw fuel up

quote:

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Originally posted by dave_424
Then I would have thought either a jet/fuel passage is blocked not allowing fuel out, or there is a split or leak in the carb rubber that isn't allowing enough air velocity through the carb to draw fuel up

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If I remember there is also an oring in the car rubber for it to seal against the head

So I wanted to give every one a quick update. I replaced the carb rubbers including the o ring sealers between rubber and block, then I stripped out a working carb and stuck it in carb number 4, result, it idled on all 4.

left it overnight and started the re-assemble the car today, whipped the carbs off as I had got the idle control wrapped around some pipes, stuck everything back on, and now she only idles on cylinders 1 & 2.

I have drained the carb bowls in 3 and 4 and there was petrol, in them.

giving up, some please give me some inspiration. loosing all faith in it at the moment.

Don't give up now, you are on the right track. You've had it running on all 4 now so you have just got to replicate that when the car is all assembled.

It's only going to be a small simple thing I expect and you will be back up and running

Sorry if this is an obvious point but have you balanced the carbs?

Stu

quote:

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Originally posted by SJ
Sorry if this is an obvious point but have you balanced the carbs?

Stu

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You did put the blanking plugs/vac pipes on the ports in the head for balancing? are they sealed well with their aluminium washers?

quote:

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Originally posted by dave_424
You did put the blanking plugs/vac pipes on the ports in the head for balancing? are they sealed well with their aluminium washers?

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right, plugged the balancer in and it was out, so I have now balanced the carbs, all are within 2mm or each other across the balancer. however, the 4th cyclinder is not idling correctly... I have temp reader and 1,2 and3 headers are reading about 240c while the 4th is reading about 140c.

any thoughts

When I'm setting mine up I normally have to balance them, adjust the idle mixture screws and balance again to get them right.

My 2p worth...

When balancing carbs or t/b's you're trying to get the engine running equally on all four cylinders at tickover.

Irrespective of what the balancer is telling you, if No4 cylinder isn't doing as much work as the other 3 (at tickover) then you need to open the butterfly slightly on no4 in relation to the other 3.

My method of doing this fine tuning was to pull the injector plugs one by one and adjust till the drop in engine note was exactly the same across all 4 when each injector was pulled. Always worked for me, maybe worth a try...?

ZX9 uses carbs

Ok, pull the plug leads instead.

When you had the idle control tangled, was 'actuating' fast idle and masking your problem?

IIRC the zx9 carbs have a T piece in the middle to distribute fuel, is the outlet to 3 & 4 restricted in any way? it could have been enough to fill no3 but not no4??

My bet would be a clogged idle jet or gallery. Have you had the idle jets out and looked through them?

sorry for not getting back earlier (broadband went down). the 4th header was running very much cooler so I thought to myself it was running rich, adjusted the idle jet to lean it out a little and bingo it was working. then started it up and it shot to 5k revs, found that the allen screws to tighten the carb rubbers to the carbs were moving the throttle adjuster springs.

so far, it appears to be fixed.

in all, cleaned a four carbs at least 3 times
changed coils
did the valve clearances and changed the shims
changed idle jets on 2
moved all carb parts from 2nd cylinder to 4th
changed the fuel hoses
balanced the carbs 4 times
tweaked the idle adjusters

so appears to be running at the moment, but never got down to the actual cause.
oh well you love and learn.


Thanks for all the help and support.
Cheers
Craig

Well done. When you don't know where to start it can take ages.

I had idle problems initially with ZX6 bike carbs on my Zetec, and for a while I though it was because I had the carbs mounted horizontally, which some people say doesn't work [I did it like that because it meant I didn't need an expensive fabricated manifold and bits of silicon hose to attach the carbs]

In the end it just turned out that the float levels were too high and after lowering them it idles perfectly plus I have the benefit of using the mounting rubbers that Mr Kawasaki designed for the job.

Stu