KZ305 rubber plugs impossible to find

The KZ250 and the KZ400 use the same ones. PN 16012-1001. I can't find any chinese aftermarket or ebay equivalent anywhere. If I could find one I would get a micrometer and get dimensions to make a few spares. Has anyone on here found an equivalent? It's crazy to me that they sell entire kits to rebuild this carburetor and that plug is not included. Plugging up the hole is one thing, but the length of the "butt" of the plug is there for a reason, as it makes contact with a flat spot on the float bowl to keep it pressed in place. There has got to be a way.

Can't you measure both dimensions from the gasket face and subtract one from the other to get the butt length ?

Wookie58 wrote:

Can't you measure both dimensions from the gasket face and subtract one from the other to get the butt length ?
 

Hmm I didn't think of that. I suppose I could do some measuring and come up with something, sure. I'll have to figure out how to shape a fuel-resistant piece of rubber to the dimensions I need. Maybe just get a chunk and whittle it down?

Three years ago, I had the same problem. I modified another plug with a small screw half way screwed into the plug and a peice of fuel hose slid over the screw head. I didn't measure, just kept trimming the hose untill light pressure was needed to push the float bowl shut. I had the bowls off the carbs this March, and the plug mods were still intact.

That looks like a simple lathe project.  You will have to determine the ID of the pilot passage, and the distance from the top of the pilot passage to the float bowl, with a gasket in place and the bowl tightened down.  A piece of modeling clay on the passage, along with some calipers, can help determine both dimensions.  Get the details, and I can use my lathe to cut a couple of plugs.  I have lots of O-rings, so it shouldn't be difficult to make the required plug.

Harbor Freight gets a fair amount of grief - and maybe some of it is deserved - but they have neat inexpensive tools like this one:

www.harborfreight.com/6-in-utility-caliper-63664.html

$1.99 for a very basic caliper. I have some scattered around the house and workshop for taking quick measurements of things that may not require surgical precision.

I'll pick up some clay this week then and get the measurements. You know, there could be a small market for these things if the dimensions ended up being spot-on and you used an appropriate rubber for fuel submersion. It boggles my mind that the guys putting out the carb rebuild kits specific to this carburetor didn't invest 10 minutes of R&D to make a part that is as disposable as any of the seals and o-rings in the kit.

That's probably where I'll end up going!

Legionnaire1856 wrote:

That's probably where I'll end up going!
 

Once you have the measurements (in SAE and in metric), try your searches again. Things like rubber plugs, oil seals, and bearings are very rarely used for exactly one thing: more often than not, you'll be able to find an industrial equivalent that matches in all the important ways but is not OEM branded.

Last year I found an elusive (and expensive) oil seal for another bike by going that route. Found a company on ebay that sells surplus equipment: they had the seal for much less than the Yamaha branded part.

You can also try Grainger.com - they might be helpful.

If you want to reproduce that plug out of rubber on a lathe consider grinding it with rough paper or use a Dremel tool with a carbide burr at a fairly high speed (work piece one direction, tool in the opposite direction) Cutting rubber with conventional lathe tools only deforms it, the stuff is like chewing gum even at a high hardness.

I use to work for a rubber company doing prototype engine mounts, ground and carved a lot of different parts using all types of tools. Grinding it will give you a smooth uniform shape.

Injected wrote:

If you want to reproduce that plug out of rubber on a lathe consider grinding it with rough paper or use a Dremel tool with a carbide burr at a fairly high speed (work piece one direction, tool in the opposite direction) Cutting rubber with conventional lathe tools only deforms it, the stuff is like chewing gum even at a high hardness.
 

Not if you dip it in liquid nitrogen first.

They are hard to find but even harder to lose, I would think. What happened to the old ones? I soaked mine in Rubber Rejuvenator  and put a smidge of fuel resistant sealant on the orifice. They stay in great again