Z900A4 float levels

[warren3200gt]

I highly doubt temp has anything to do with it Andy. Cold air past the tank and the carbs are effectively isolated from the cylinders by the rubber intakes so doubt the fuel is gaining that much temp until its drawn into the head.
I thought you'd trying swopping floats 2 & 3 and the issue remained with no 3.?

It can only really be seepage from the thread or a crack I'd say. When you re wet tested them did you leave the tap on for a reasonable time to see if the level creeps up on no 3?

[sprint]

As I implied, I am grasping at straws to try and understand what is going on in trying to relate it to temp?

I initially raised the tang on No 3 so that the valve was barley open and the float more or less only had to move to close it and it still remained high. I then swapped No's 3 & 4 as No 4 was OK and No 3 was high. But when I tested it yesterday No 3 remained high and No 4 was OK, sort of eliminating the floats?

When I did the original off the bike wet tests I did not leave No 3 or any of them for any length of time. As all of them were high there was no reason to suspect anything specific to any particular carb.

As indicated I have taped the floats of No's 3 & 4 up and left them for around an hour and nothing has leaked out of either of them. It would need to be a fairly substantial leak which I would have thought to be obvious if with the valve closed it continued to leak past it via another route, leaking thread or a crack which would not just appear and disappear again?

[warren3200gt]

This really makes no sense.
Something is causing it, but you've ruled out any possible cause and the issue remains..
I can't imagine how frustrated you must be feeling, its bugging me and its not my bike!

[sprint]

Yes it really does not make any sense.

As indicated, I left the float bowls off on No's 3 and 4 with the floats tapped up and the petrol tap on for around 4hrs, not a drop of petrol has fallen onto a blue paper towel under them.

If there was a leak on the threads of a crack somewhere it would have shown up after that length of time. Also with the bowls fitted if there was a continuous leak after the valves had closed you expect petrol to be flowing out of the overfill pipe, which again has not happened.

I am at a loss of what more I can physically do or check other than now wait for the replacement new floats and see if they make any difference?

If anybody else has any suggestions or thing to try pleas let me know.

[Al]

I fitted aftermarket float bowl gaskets to my previous carbs. They were too wide across and fouled the floats.
Are the choke plungers confirmed as being adjusted to fully seal?
The original pic you posted (sooty plugs thread) showed one plug as having a 'clean' ring round the centre electrode. The most recent pic shows the same,... but may be a different cylinder depending on whether they were in the correct order in the first picture!! Or if you have swopped the leads over. I got this earlier this year and ended up replacing the coils because one was internally shorted. The effect was 'plasma' bleeding across the spark plug gap and not a well defined spark! The co-responding plug on that coil had a spark but it was white and intermittent where the other coils' plugs both had bright blue sparks.
Swopping the leads over between plugs (in my case between two and three) did not fully highlight the problem or show it to 'move' because necessarily both plugs on the same coil were below par. The giveaway was the area of 'cleaning' around the centre electrode of one of them!
AL

[sprint]

Thanks for the reply.

I have checked that the gaskets are not fouling with the floats and they are not.

Plug take from the same cylinder, No 3 which is the one that also has the problem with the high wet float level. Hence really needing to sort out why before moving onto other potential sources for the plug to be black and sooty as I feel that is the most likely cause for it?

The plungers have been fitted with new seals and I can see no reason as to why any of them are not sealing and as previously advise there is still a problem with No 3 having a high petrol level.

If I can get to the bottom of why the wet level in No 3 seems to be inconsistent and stop it I feel that the plug problem may also go away?

[moizeau]

Another thing that can cause an inconsistant fuel level could be the float pin binding. Crap build up on the pin or in it's mounting holes on the legs of a deformed leg.

[sprint]

Thanks

All those that you have suggested have been previously check and found to be OK.

[sprint]

Still waiting for the replacement floats, but increasingly believing that they will have been a waste of money?

Took the bike out again doing around 40 miles.

Bike is riding the sweetest I can remember, smooth and responsive, ticks over nicely at 900/1000 rpm without any issue and the stuttering and stalling off the closed throttle is much improved.

However, did a 60 mph plug chop and No's 1,2 & 4 OK but No 3 black and sooty. So it seems that there is a problem throughout the rev range?

I had changed the float that was in No 3 giving a high wet level with No 4 that was giving a normal wet level following the last ride. But despite them all giving a normal wet level before starting off when I got back and checked them again No 3 was again giving a high wet level and No 4 a normal wet level, so don't really think it is a float issue, but why does No 3's wet level rise after a ride. I suspect when I check it again later today it will be back to normal?

However, there is clearly an issue with No 3 running remaining rich at the higher rev range, at least up to 60 mph or around 4K.

It has a new plug, so it can't be that and all the jets were cleaned ultrasonically and the passages cleaned with carb cleaner and compressed air with none indicating any blockages?

The pot set up OK using the colourtune, so what are the likely causes for the plug to remain black and sooty even at the higher rev range?

No 3 in the plug guide seems to look the most appropriate, clearly a rich mixture.

I have electronic ignition so can I just simply swap N's 2 and 3 plug lead or do the coils and/or the trigger from the ignition also have to be physically moved?

[zed1015]

You can swap common leads 2-3 with each other to eliminate plug cap or lead issues as they share the same coil and fire simultaneously.

[sprint]

Thanks

The No 1, 2 & 4 suppressor caps resistance measure around 4K8 ohms No 3 around 5K4 ohms, slightly higher but not enough I would have thought to be causing the black sooty plug problem?

[sprint]

Been for another ride.

No 3 remains black and sooty at any rev point, so not due to lead or plug cap, so indicating a carb problem?

Current plugs are NGK B8ES so fitted a B7ES, hotter plug, to No 3, remained black and sooty. So even with a hotter plug it remains black and sooty.

Did pressure test. Each one is around the 100 psi, not great but they are all the same so reason there for the problem with No 3. Hot engine and throttle fully open, but air filler still fitted.

Can't see that changing the floats is going to make any difference, when they arrive and it does not seem that the choke plunger seals weren't a problem?

Totally lost what to do now. Problem seems to be specific to the No 3 carb, but what?

What are the chances of getting another body/carb to try or some specific areas things I need to look for?

Really loathed to even have to think about taking the carbs off (getting them on is the real difficulty) let alone physically doing it!

[warren3200gt]

There's only 4 things that go into a cylinder. Any of them can cause black plug.
Compression, all seem similar so unlikely to be that.
Fuel air mixture, all colour tuned OK.
Spark, swopping plug lead with no2, the issue didn't move with lead so kinda rules that out unless you've a duff plug and didn't move that also.
Oil, worn valve guide seal. Worn or broken oil scrapper rings.

The bit that makes no sense is the varying fuel bowl level on number 3.

If I had a set of 26's laying around I'd send them to you so you could try them and rule carbs in or out but I don't unfortunately.

[sprint]

Don't believe that there is any problems with worn guide seal or any broken rings as the plug is dry and sooty that wipes off with your finger and all the rest or your list have now all been tested and no issue found.

New B8ES and B7ES so they can't have both been duff.

I'm now at a dead end as there is nothing more for me to try, very depressing!

It remains a total mystery as to what ever position I set the tang on the float that it goes to the high level position but does not overflow.

I'll put a wanted ad to see if somebody has a LH 26 carb body or complete carb failing that I'm lost at the moment. Does the body and slide have to be matched/worn together or if I can get/borrow a body can I use my existing slide?

[warren3200gt]

Ideally body and slide are kept paired but needs must.