VM24 carb questions

The carb questions I have are for the VM24's on my '78 KZ650.

I'm in the process of cleaning them out (Stabil didn't protect them ) from sitting for a few months, and I noticed a broken o-ring on one of the fuel rails/fittings (shown in pic below), and the other o-rings appear to be ready to die as well.
It wasn't leaking from there, so I'm guessing it broke as I removed the fuel rail/fitting.

Kawi shows the fuel rails/fittings as "assemblies" (part#s - 92005-1009 qty 2, 92005-1010 qty 1) and doesn't show the o-rings seperately.
Not wanting to have to remove and disassemble the carbs AGAIN because they're leaking from just using any o-rings on these rails/fittings, I'm wondering if anyone (WG?) knows if these are made of viton, what their dimensions are, and if there's a source where I can get them in the correct size/material?

Next question:
Forward of the fuel rails/fittings and higher up on the carb bodies, there are what appears to be sections of rubber (vent?) hose that connect one carb to the other.
I have the hoses that go from carb 1~2 and 3~4,

but it appears that the longer hose that goes from 2~3 is missing.

Is there actually supposed to be a hose there (it has open passages on both carbs at those spots)?
And are these simply just pieces of black fuel line, or is it made of some "special" type of material?

Last question:
I have the choke assemblies (plunger, cap, spring, etc) removed for cleaning, but I don't see anything in the way of a plunger seat that can be flipped over to "renew" a leaky choke as I've seen posted about before.
There is rubber within the ends of the plungers, but it doesn't appear to be removable.
The rubber doesn't look damaged or even worn, so should I be ok with just cleaning them and stuffing them back into each carb, or am I going to have to bite the bullet and buy new plungers...IF they're even available anymore? :pinch:

Post edited by: RetroRiceRocketRider, at: 2007/04/08 15:34

Get the Viton or Nitrile O-rings (not sure of the size). You will need a metric size as the STD sizes are just close enough not to fit or work.
The center rubber hose connector that is "missing" actually doesnt have a hose there. The 2 outer hoses connect the 2 pairs of float bowl chambers together (vent) and each pair of carbs vent through the 1 hose (2 vent hoses for 4 carbs). The connectors are just a std. gas hose.
I'd just leave the plunger pads alone if they seam fine and not flip them over. They are easily destroyed when being removed.
Fish

Thanks for the info Fish!

I initially thought that there might be a hose missing between carbs 2/3, since my wife had dragged me away to perform a plethora of "honey-dos" at mid-disassembly and I wasn't able to return to them until several hours (and beers:whistle:) later.
I figured that particular "phantom" hose had simply rolled off the workbench and dissapeared into never-never land.
Upon closer inspection, I realized that the throttle linkage spring was directly where the hose would sit, so obviously there really couldn't have been a hose there afterall.
Good to know that it never existed in the first place....Phew! :S


To be honest, I never even considered the metric vs standard sizing to be a factor on the o-rings, but that is certainly a good point. And I'll be sure to only use either Viton or nitrile o-rings.

Now I just need to find some is all....and of course finish cleaning the carbs before re-installing them. :whistle:

Thanks again!

Post edited by: RetroRiceRocketRider, at: 2007/04/08 19:28

Chris,can You measure the o.d.of one that's on the union in the pic?
I have a couple spares here,that are for My 29's and if they're the same,then I know where You should be able to get some...

Or better yet,check out Sudco.
There's measurements here in this link.

www.sudco.com/carharori.html

I got Mine from Sonny(Member here)a while back,so You could always check with Him also...

Oh AND...don't forget about the ol standby...teflon tape DOES work.I used it on My 26's,and it worked right up to where I installed the 29's,which was about 3 seasons.

Post edited by: Sandy, at: 2007/04/08 21:33

Sandy,

I did some checking around, and one site showed that all of the VM carbs used the same o-rings in various areas (choke plunger, drain plug, fuel joint, etc), so the info you have as far as measurements should be spot on.

The o-rings currently on there are pretty compressed, so getting an accurate OD measurement from them isn't going to be possible. Plus they're really dry, and I'm sure they'd break like the first one did if I tried to remove them to get an ID measurement.

I don't have calipers here, but I'll take the removed fuel rail/fitting to work tomorrow to get the ID measurement from the slot where it sits in. I'll also take a carb to measure the opening where the fuel rail/fitting fits into to get a rough idea of the o-ring OD.

I remember the teflon tape trick, but the next time I plan on removing/disassembling these carbs will be for rejetting to fuel the big bore kit that will eventually be in the bike, so I'd rather do it right the first time and not worry about potential leaks.

I can't recall the size of the oring used on the fuel pipes. It is different than the pipes on the VM29. A bit smaller. I buy those orings by the hundred lot and will have to check the size. Most of the orings used in carb applications are nitrile rubber. If one of your orings cracked, as shown in the pic, they are all old and hard and should be replaced.

The rubber bit between 1&2 and 3&4 is a vent hose. The #1 carb bowl vent goes up and out the hole in the side to connect to the #2 vent which has the external brass vent fitting... same for 3/4. There is thing on the #2 and #3 carbs that LOOKS like a vent passage but it is blind. They use these casting for a variety of applications and so the casting is there, although blank.

The float plunger has a rubber pad. If you are REAL careful, this can be pried out and flipped over. It is best to just replace the pad because while the pad will seat better on the virgin surface than on the surface that has been contacting the plunger seat, it is still real old material and probably on the hard side.

on a similar topic where can the "choke" plunger pads be purchased.

----

Ok, just thought I'd post an update.

Like WG said, if one is broken there's likely going to be more like it - found 3 more broken.
I was planning on replacing all of them anyway, which is cheap insurance IMHO.

So I took the entire carb rack in to work with me the other day to "borrow" the o-rings for the fuel rails out of the nitrile o-ring assortment I have in my work area.....just checking sizing mind you..*cough*bull$!#t!*cough*. :whistle:
Found some that fit perfectly and replaced them all, although I have no clue their actual size since the bin they were in wasn't labeled. :S

Finished cleaning up the carbs and re-assembling everything. Tossed the slightly hard airbox boots into the microwave on a paper towel for a min, then flipped them over and "waved" them for another min.
They softened up to near new, and I had all of them installed in less than 5 mins! :ohmy:

Now the odd part, it starts (using very little choke and within about 2~3 revs of the engine), idles (almost no fluctuation), and runs WAY better than when I had thoroughly cleaned the carbs a couple of years ago! :woohoo:

I don't recall doing anything diff from the first cleaning, so I'm puzzled. :huh:
I'm not complaining mind you, just trying to figure out what I MIGHT have done differently.

So what does this all mean you might ask?
It means that after I renew the registration tomorrow at the AAA office, I'll be riding it instead of the ZN on the West Coast group ride later this month! :woohoo:

I know this is old, but I was doing some searches for orings etc, and as always, whenever doing technical searches on Google, a KZrider link shows up

Anyway, use Viton (Dupont trademark name for fluorocarbon elastomer) if you can get it. Nitrile doesn't stand up as well to modern gasoline (with benzene etc.)

Here's a place that has what I needed for some Keihin's, buit they may have what you need too. Scroll down for some o-rings by metric sizes. The sizes are somewhat nominal, so you may want to get an assortment close to the size you need.

www.crc2onlinecatalog.com/gl_carb_parts.htm

Post edited by: loudhvx, at: 2007/05/16 13:30

mic57 wrote:

on a similar topic where can the "choke" plunger pads be purchased.

Here ya go!

www.z1enterprises.com/detail.aspx?ID=79