Carbs, bloody carbs

[m1ks]

First of all, is there an easy to way to check if my Z650 carbs are Mikuni VM24's as the manual states, I cannot find a single indentifier on the carb bodies.

Recently had a ride and found that at least two of the carbs are pissing out fuel of the overflow pipes, I discovered a knackered petcock which i've sorted but as soon as the engine starts and runs it's pissing all over the place.
So carbs off and and i've looked only at one so far.
it's running a 107.5 main, (book states 100) though it was definitely running lean with the pod filters it had when bought and seems to be running well with good combustion colours on the plug with a standard filter on.
Anyhow the question I have is
the manual states that float level is 30mm +-1mm, all well and good the level in the first checked is about 22mm, bending the tang to get a reading of 30mm will push it to the limit of it's downward travel and just doesn't seem right.
has anyone set the float height on the VM24's on a Z650? if so what to and how did it seem, just seems way out 30mm to 22mm and the tang looks like it's practically untouched.

[trikerdrew]

Try dropping these guys a line

http://www.nrp-carbs.co.uk/

this looks interesting.Least by pics you'll know if they are the carbs your dealing with,

http://www.mikuni.com/pdf/vmmanual.pdf

regards

drew

[kev edwards]

Hi m1ks , just looked it up , Vm24's 23mm + or - 1mm , also check to see if your float needles are sticking , and that your floats are not filling up with petrol , as both of these will make it overflow.

[m1ks]

Thanks guys, will look at the links drew.
Thanks for the measurements Kev, confusing as the manual definitely states 30mm +-1mm. Can I ask where you sourced this measurement, is there a resource for carb fettlers somewhere I don't know about, (i'm prepared to wear a cloak and learn the secret handshake):D

My suspicions are a worn / sticking valve or seat or damaged float regarding the flooding, as it's just recently happened, was just curious over the float height, I wonder if mr Haynes measures with a different method?
Once i've stripped and checked the other three i'll ascertain if a new set of needle valves wil be required

Cheers,

Mike

[m1ks]

Just checked the PDF.
It's the right type of carb but a bank of four roundslides, I should have stated model number as VM24ss, apologies there.
Obvious difference being that the carb slides are linked to an actuating rod rather than a conventional pull cable and return spring which sits between carbs 2/3 on this as you'd expect to see on a four cylinder bike of any type.

[m1ks]

Have measured the internal diameter of the carbs, it's 26mm, does this mean they are in fact VM26SS? i'm assuming the 24 refers to the mm of the ID, does anyone know if the F2 model used VM26 carbs instead of VM24?

I'm still working on the principal of a 23mm float height as they all seem to be around that area and appear to be previously unadjusted.

[kev edwards]

Hi M1KS , i got the measurements from the genuine Kawasaki Kz 650 service manual , to get the carb size measurment you need to measure the opening nearer the slide as the front edge of the carbs have a tendancy to be a little bigger , i had a little trouble with my float valves at one tme , they were sticking in the guide so i used 1000/1200 grade wet and dry paper and gave the three ribs on each needle a light rub , now they don't stick at all , also the F2 models used VM24SS carbs these also have three ribs around the slide housing , about 1982 they changed to CVs they are BS32s .
I'm not sure about the 30mm level the manual says service fuel level , but stick with the 23mm level and you will be ok.
No secret handshakes here just a wealth of hard earned experience on this site and most are happy to share it with others.

[m1ks]

Update.

All carbs stripped, cleaned blown through with compressor, rebuilt, refitted.
Leaking tank drained, (you should have seen the crap in it, looked like chunks of resin like material, previous badly applied petseal maybe?, sounded like someone had thrown a handful of ball bearings in there)
Replaced with better tank i'd bought for respraying, fitted petcock and checked leak free, all OK.
connected, primed, looking good, fired up, realised i'd not connected throttle cable, oops, removed tank, refitted and tank back on there, spun engine, whirring but not catching, aaaarrrrghhh, (starter clutch on it's way?) bloody hope not, wheeled bike out of shed to get around it easier, tried again, spun over and seems OK, started a few times and spinning OK.

Left running for a bit, getting quite pleased with myself, ran it back and forth a bit, (becuase it's been a while since i've ridden it), then, dammit all to buggery, a puddle under the bike, watched it and it's only one carb, extreme right.

So, next step, new set of needle valves and seats I guess, the fitted ones looked OK, slightly worn, barely grooved but I guess enough, filtered fuel back into tank and filter on petcock so shouldn't have gotten crap in.

Was going to fit my new thruxton type silencers and go for a run but oh well.

During the typing of this my son managed to spill his tray of tomato soup all over me and it's now pissing down.

[kev edwards]

Hi M1KS , with all that crud in the tank an in line fuel filter would be a good investment only a few quid.

[m1ks]

The replacement tank is in pretty good internal condition, i'll not be re-using the crappy one anyway.
I'll no doubt fit an inline filter though I admit I don't like the look of them on an exposed bike where it's visible, I don't mind if it's well hidden.

[BShaw]

"During the typing of this my son managed to spill his tray of tomato soup all over me and it's now pissing down."

Keep your chin up mate, we have all been there.

Filter first then needles

[m1ks]

Thanks for the kind words
I wouldn't have minded if it was another soup then I could have eaten my way out of the puddle on the sofa, unfortunately I detest tomato soup.
Regarding the pissing down weather, the only downside there is cramming back into the shed and struggling around everything, but that said if not the rain then it's the midges, you just can't win eh.

Kev, do you have a copy of the factory manual, or failing that just the measurements and specs?
float valve
Fuel service level, (checked with tube tester)
Valve clearances and so on?

That would be most appreciated.

So before I fork out the £40 for new valves and seats d'you reckon it's worth attacking with some W'n'D or should I just say stuff it and go for the new un's?
They really didn't look bad, even under a loupe, just the tiniest hint of a line, it did intially seem to be holding too, not until I ran it forward on the yard and gave a few revs that the wetting happened.
I've left all the floats at 23mm BTW

[BShaw]

Some thing I just remembered..... My dad told me to check a float needle with my teeth, you can feel if there is any groves in it by rubbing it gently on your front teeth..... that's if you got any ... I know what you jocks are like , just coz your bike don't work , you kiddy split soupe on ya, ya got nat bites and it's pissing down, you go down the pub get bladdered, and nut some ginger bloke in a kilt outside the chip shop....but what ever you do don't go home and kick the bike, that's what your mrs and cat are for !

Teeth thing does work for all sorts of things.

[kev edwards]

Hi M1KS , manual to big to photocopy would take me days , so heres some measurements.
vm24ss
main jet 102.5
needle jet 0-4
needle 5cn15-4 the four meaning the clip being in fourth groove from the top.
pilot jet 15
starter jet 40
throttle cutaway 1.5
float height 23mm + or minus 1mm
service fuel level 3.0mm + or minus 1mm

valve clearances are set when cold and are 0.08 - 0.18 mm

as for the 30 mm level that should actually say 3.0mm

i would go for the 23 mm float level . The needle valves i would lighty rub the ribs , as when i put new in mine they still stuck in the guides a couple of light srokes cured this .

As it appears to be running good i would be inclined just to sort out the needle valves and leave the rest as is , based on the saying if it is'nt broke don't fix it.

[m1ks]

Update.

First of all i'll ignore the scots jibes BShaw, and I take offence to your clearly misguided info, we don't nut ginger blokes in kilts, we go for english tourists
Or German tourists, we're an equal opportunities nutter society here y'know.
Funnily enough most of the Kilt wearers here are tourists, funny to think that they seem to think we all dress in them, I only realy wear mine for special occassions and when on hol's just to see peoples faces, the Americans love it though.

Kev, thanks for the info, like you say, the level should probably be the service level at 3.0mm, it is odd as all the Haynes books i've had previously have been good.

Anyway, removed, stripped and performed the 'enhancement' as described, propped them upright and filled the bowls through the inlet pipe, initially OK then no #3 started leaking, stripped and re-did this one and re-tried, fingers crossed so far OK, am going to leave overnight to see then refit and retry on the bike.
If it's a no go at least a new set of valves and seats is £9 each, not too bad.