Tubed to tubeless

[masterofpuppets]

hey people,
i have a old cb250n that im currently working on to bring up to standard. got it given to me a while ago now, and its been sitting in the garage since, so i thought i'd make a start on her. the thing is i just noticed that the bike has tubed tyres. i was wondering is it possible to go tubeless on a rim designed for a tubed tyre.
my guess is no, but i thought i'd ask.
was also wondering about the size, the current ones on there are quite old (possibly original) and in imperial(?) sizes. 3.5 by 18 or something. waht does that sort of eqate to.
and finally.... if i have to stick to tubed, are there any decent rubber compounds out there for tubed. i know they'll be nothing close to the gpr70s on the zxr, but at least some stick will be cool..
cheers,
Nick

[Ixion]

Are the wheels wire spoke or cast ? If they are wires, you are out of luck, BMW are the only people who make wire wheels that can take tubeless tyres

[masterofpuppets]

yeah i thought that might have something to do with it...
they're not spoke, cast i guess, even though they seem more like they were beaten out of sheet alloy then cast...
so is it just a matter of putting on a valve on the rim or what?? what about the bead??

[Ixion]

Oh, they sound like they may be those funny Honda wheels I don't know about them, PM Bonez he'll know about it.

[What?]

Oh, they sound like they may be those funny Honda wheels I don't know about them, PM Bonez he'll know about it.

They are called Comstar (Honda's version of Astralite). Pretty sure that all Comstars are tubeless type, however an easy check is to look at it - it will be stamped on the rim as to what type it is, along with the measurements. Another easy check is the valve stem hole size - tubeless valve stems won't fit through the hole on a tube-type rim.

[Lou Girardin]

What what said.
You can also use tubeless tyres with tubes in them on a light, relatively low performance bike like that.

[DEATH_INC.]

Pretty sure the 250n does have comstars, and also pretty sure they're tubeless, but any half-decent shop that sells tyres will be able to tell ya.

[mouldy]

Are the wheels wire spoke or cast ? If they are wires, you are out of luck, BMW are the only people who make wire wheels that can take tubeless tyres

Bollocks Viragos run a tubeless spoke and they're Yamaharleys

[mouldy]

Pretty sure the 250n does have comstars, and also pretty sure they're tubeless, but any half-decent shop that sells tyres will be able to tell ya.

Not all comstars are tubeless but from memory I think the 250Ns are .

[masterofpuppets]

yeah nah, thanks for all the help people,
i spoke to bryce at buckets n bits, helpful as chap, he said that tubeless can be chucked on them regardless of what.
took it to the shop though, and they said they wouldnt do it as the rim wasnt stamped tubeless. ended up getting a decent tubed tire in the end... now just gotta keep my fingers crossed and not ride on the left hand side of the road to avoid picking up shit
cheers all