Rims and Tires

So my 83 kz650 by the looks of it has tubed tires, im having a hell of a time finding a matching pair to replace them that are tube type. Since these rims arent spoke type can they somehow be upgraded to fit a tubeless tire? i know that the valve stem might be the problematic part since its held in place by two screws.

any input? thanks

According to Kawasaki.com the 1983 KZ650-H3 (CSR) had cast wheels that did not require tubes (see image below - notice tubes are not shown). If yours are the original wheels I believe they should have the word "TUBELESS" cast into them someplace. However, unless you are familiar with the total history of the bike, don't assume they are tubeless unless so marked because they could have been swapped from another bike with tube type wheels that look identical.

One other indicator of whether or not a wheel is a tubeless type is the fact that the tubeless wheels normally have a ridge that runs around the inner surface of the wheel near where the bead of the tire sits to prevent the tire from being bumped inward toward the center of the rim which would cause it to immediately go flat. Take a look at the second image below.

If your rims are the type that require tubes you can run tubeless tires, BUT NOT WITHOUT TUBES. You absolutely MUST use tubes or the bike will be unsafe.

The really good news is that it is perfectly safe and normal to run tubes in tubeless tires, so don't even try to find "tube type" tires. Tire that are marked tubeless are what we all use along with tubes except when the wheels have the word TUBELESS cast into them. Ed

The front wheel from my 750E2 is imprinted Tubeless, but doesn't have those ridges. Likewise, I have a Suzuki GS front wheel that's the same way. Apparently Kawasaki and Suzuki did not think the ridges are critical. The main difference between my wheel and those that came with tubes is the machining of the valve stem hole.

A LOT of guys on the GS Resources have converted tube type wheels into tubeless by machining the valve stem hole to accept a tubeless tire valve. I used to be against this sort of mod but after seeing these tubeless rims without the ridges, I can't justify my opposition anymore.

It's interesting that the 1981 KZ750-E2 does not have the ridges. That's one of the earlier KZ's with tubeless rims; I think 1980 was the first year to offer tubeless. Just speculation, but I wonder if the reason the ridges were added to later KZ wheels as shown in the image I posted was that problems were reported by some owners. If that was the reason, and if the problems were safety related, it probably would take less than one in 10,000 to scare Kawasaki into changing the wheel design. In any case since the 1981 KZ750 wheels are marked Tubeless, if the 1983 KZ650-CSR wheels are tubeless type I suspect they will also be marked as such. Ed

took a look at the rims themselves and they have nothing stamped on them whatsoever, the tires literarly just have the zie on them and says nothing at all about tube or ply rating (they are old as hell)

what worries me a bit about the stems is that the current stems are yheld in place by two small set screws on each side of the stem, i dont see how i would convert that into tubeless even if i could without welding onto a cast rim.

For whatever reason, the official Dunlop motorcycle tire site includes the following:

Note: Not all cast wheels, whether aluminum or magnesium, are suitable for tubeless-tire fitment.

Mount tires as tubeless only when the wheel manufacturer recommends it. Some spokeless rims require tubes. With a tube inserted, a tubeless tire may be fitted to a tube-type wheel.

Would be interested in seeing it suggested by a technologically competent and financially responsible source that simply fitting a tubeless style valve stem into a cast tube-style motorcycle wheel will safely convert the tube-style cast wheel into a tubeless style.

This would assume that the tube-style wheel casting is air-tight (i.e., not porous enough to allow air pressure to escape).

Perhaps if the tire bead is sufficiently stiff, the raised rim would become unnecessary?

Have seen spoked tube-style automobile wheels epoxied inside the rim to prevent air leakage when a tire is mounted without a tube.

The risk involved may be less critical when dealing with automobile wheels and tires.

In any event, here are excerpts from the FSM supplement pertaining to the KZ900-B1 LTD's genuine Morris Mag wheels that were fitted at the factory:






Have never risked running tires without tubes on the mentioned Morris Mags.
And would not elect to bore a hole in them to adapt a tubeless valve stem.

Good Fortune!

worior1 wrote: took a look at the rims themselves and they have nothing stamped on them whatsoever, the tires literarly just have the zie on them and says nothing at all about tube or ply rating (they are old as hell)

what worries me a bit about the stems is that the current stems are held in place by two small set screws on each side of the stem, i dont see how i would convert that into tubeless even if i could without welding onto a cast rim.

I have never seen that before. PLEASE post a picture of it. Also, if there are other markings cast into the rim it would help us identify it as an aftermarket, stock, etc. For example, the image below shows markings on one of my KZ650-C1 wheels.
Thanks,
Ed

I no longer remember where I pulled this from so can not give proper credit. But you may find these pages that appear to have come from a UK mag in 1980 that discuss the different rim and tire types and the issues associated with them.

That article is great in that it shows the different wheel profiles at that time and gives other good information; thanks for posting it.

However, the author missed the boat when talking about the possibility of tires slipping on rims. He stated “…despite there being top-level enquiries going on in Europe and Japan, or so were told, the accidents involving tyres slipping on rims and pulling out the tube valves were very few in number, confined to a single type of tyre ……”

That statement is a bit misleading. While I have no idea of the number of accidents, the number of incidents in which the tire slipped on the rim and ripped out the valve stems was not “very few in number.” It was not particularly uncommon and it most certainly was not confined to one type of tire (at the time mine was a huge Goodyear). Example – it happened to me on my BSA in busy traffic and it was all I could do to maintain control of the bike while the back end swung wild, wide arcs back and forth (and of course some a-hole in a car was on my tail blowing the horn thinking I was doing stunts)! In my case I somehow managed to hang on and keep the bike from crashing, so the author’s statement ignores that and who knows how many other similar incidents that did not end in a wreck. Isolated incident? I don’t think so. When I told the folks at the dealership about it they said they laughed and said they had seen and experienced the same problem firsthand. They said it was particularly common in racing and in aggressive street riding (guilty as charged) and that my large tire may have provided more traction than the friction between the bead and chrome rim could tolerate. They even had a solution – drill small holes around the rim and run short sheet metal screws through the holes and into the bead of the tire. I did this and no more slipping. Several of their bikes already had the treatment. No doubt this is why Kawasaki provided rim locks on the rear wheel of many of their bikes; the sheet metal screws did not contribute much to a polished look. :laugh: :laugh: :laugh: Ed

Was lucky to get this pic just before Ed vanished in a cloud of smoke. :lol:




Good Fortune!

Here's a 1980 KZ550-Ltd cast alloy Rr wheel. Tubeless is cast into one of the spokes.

martin_csr wrote: Here's a 1980 KZ550-Ltd cast alloy Rr wheel. Tubeless is cast into one of the spokes.

Interesting that Kawasaki also used the same rim profile with the raised ridge on the spoke wheel that requires a tube.

Would suspect that discussions at the Inner-Tube Round Table show a preference for a more comfortable life with no raised ridges or at least the lowest ridges available. :lol:

Good Fortune!