Tubeless back rim for KZ650D

I replaced my back tire last night. My 1979 KZ650-D2 has alloy rims, the front one is tubeless so I was surprised when I tried to inflate the back tire and it wouldn't grab the bead.

I looked in the forums and found out that my rear rim is a tube alloy, which means that a tube is required.

I don't know how it happened that I have one of each kind, may be the front was replaced by the previous owner/s. I'd rather have both tubeless rims, I was wondering which year and bike will have an alloy rim compatible with the KZ650, I have seen a few from KZ1000 that look alike and are 16" but I'm not sure.

Can somebody provide some info on this?

The KZ650-D2 came equipped with tube-type alloy wheels front and rear. Does your front rim actually have the word "TUBELESS" cast into it? If it does not it requires a tube. If it is marked "TUBELESS" someone did swap out the original. Ed

Good Fortune!

I used to think all tubeless wheels had those ridges, but I recently found a Suzuki GS front wheel imprinted with "tubeless tire applicable" but NO ridges. Very strange.

Nessism wrote: I used to think all tubeless wheels had those ridges, but I recently found a Suzuki GS front wheel imprinted with "tubeless tire applicable" but NO ridges. Very strange.

Strange, indeed.
My understanding is that when mounted without a tube on a ridge-less rim, hitting a bump risks dislodging the tire from the rim, resulting in an instant flat.
Not a happy occurrance while leaned over and cooking through a curve. :pinch:

Good Fortune!

You'd think that if a guy hits a bump hard enough to dislodge the tire from the rim, the rider is probably going down in a split second anyway, so it may not matter if a tire deflates???

Here's a KZ550-Ltd cast alloy wheel - it's marked tubeless on one of the spokes. You can see that it has small ridges & from memory the 650-CSR tube-type wire spoked wheels have the same ridge profile.

martin_csr wrote: You'd think that if a guy hits a bump hard enough to dislodge the tire from the rim, the rider is probably going down in a split second anyway, so it may not matter if a tire deflates??? . . . .

The risk is greater with under-inflated tires (unfortunately, a rather a common condition).
"Dislodge" probably wasn't the best descriptive word -- and doesn't mean that the entire tire escapes or dismounts from the rim.
All that's needed from the bump is creation of a sight passageway for air pressure inside the tire to escape between the bead and rim. Bump - whoosh - flat.
Recovering from hitting the bump, which may be an unexpected and/or unavoidable bump, is already difficult enough without having to also contend with a flat tire.
Especially while heeled over clipping through a corner.

Opinions differ. And some folks persist in mounting tubeless tires without tubes onto tube-style rims, regardless of advice to the contrary (from people way smarter than me). They either don't believe the advice, or choose to accept whatever risk is entailed. Here's hoping they never experience having to learn the hard way.

Good Fortune!

I wouldn't go tubeless on a tube-type wheel. However, there has been some debate as to whether or not some of the KZ tubeless wheels should in fact have a tube because of the lack of prominent ridges. I think steell has mentioned it.

martin_csr wrote: I wouldn't go tubeless on a tube-type wheel. However, there has been some debate as to whether or not some of the KZ tubeless wheels should in fact have a tube because of the lack of prominent ridges. I think steell has mentioned it.

. . . wouldn't go tubeless on a tube-type wheel. -- AMEN!

Regardless of the circumstances, a sudden flat is undesirable.

Hitting a pothole -- or maybe a curb -- is probably more common, and could be better examples than hitting a bump while cornering (a worst case scenario).

Consider hitting a pothole while going straight ahead.
Might even be done with enough force to dent a wheel rim.
Is often recoverable, but more difficult to recover where the tire flattens.

Scenerio #1. Tire and tube on tube-style rim. Reasonable probability that tire remains inflated following impact.

Scenerio #2. Tire (without tube) on tubeless rim. Reasonable probability that tire remains inflated following impact.

Scenerio #3. Tire (without tube) on tube-style rim. Risks instantaneous deflation of tire.

Likely same if hitting a curb.

Dunlop says, "Tubes are a crucial part of the tube-type wheel assembly."
"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."

Dunlop's new tire warranty excludes "Tubeless tires fitted without innertubes to rims requiring innertubes."

Besides the suspected propensity for deflation as mentioned in my examples, I don't know if there may be other and possibly more important reasons underlying Dunlop's admonition.

Good Fortune!

And if a guy doesn't check his tire pressure regularly or develops a slow leak during a ride, the risk is exacerbated. Or if the suspension needs attention.

As to what tubeless wheel the op could use on his SR, I don't know. My guess is the 750-Ltd-4, but the Rr brake is different - the disk & caliper aren't the same, so alignment etc might be an issue. The hub stuff looks very similar & the 750-H1 has some of the same hub parts, but not the disc & caliper.

All this is true, if the rim is designed for a tube then it should have a tube. The question was though, which model/year bike has tubeless allow rims that would fit a KZ650D2.

I think it will be easier just to get a tube rim and put both with tubes.

750 twin and 1000 wheels will not fit, they have a larger axle diameter.

After giving it some tequila induced thought, I can't think of any wheel that will do what you want.

I suggest doing a front rear suspension upgrade. My nephew (bless his screwed up soul) installed 83 GPz750 suspension on his 79 KZ650D SR. I recommend something much newer.