Author Topic: CB750 K3F - AKA The Red  (Read 118756 times)

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Offline RAFster122s

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Re: CB750 K3F - AKA The Red
« Reply #500 on: March 14, 2023, 09:23:29 AM »
My 78 CX has Comstars and they are marked Tubeless. Are yours marked Tube?
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Offline 70CB750

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Re: CB750 K3F - AKA The Red
« Reply #501 on: March 15, 2023, 03:12:14 AM »
My 78 CX has Comstars and they are marked Tubeless. Are yours marked Tube?

Interesting, I believe for CB750 they went tubeless in 1979.

My wheels are 78 and there is no marking on them.  I did a lot of research before I went that route, but it worked out well.  The only difference from tubeless rims is the valve hole. Some people tap it and use a valve from water tank, but that NAPA valve works for me. 
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CB750K3F - The Red
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Offline grcamna2

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Re: CB750 K3F - AKA The Red
« Reply #502 on: March 15, 2023, 11:30:50 AM »
I've changed a few tires on different wheels and added valve stems to wheels.
I notice there is a difference between wheels that are marked 'tubeless tire applicable' and those that are not.
The wheels that are marked Tubeless have very wide bead surfaces inside with a designated 'lip' on the inside edges of each bead shoulder that makes it a bit more difficult to 'seat' the beads initially when installing the new tire.
The Tubeless designation on the wheels has a safety feature in case the tire was to have a blow-out and instantly run flat while a person is riding it:the tire stays 'seated' when that happens. I haven't had that happen to me,and God help me if I did..  :o
A tire could conceivably lose bead contact as I'm describing which would wrap the tire up around the rim in a strange way and expose the metal rim surface to the road;to me that's a 'worse case scenario',especially on a Front while I'm going around a corner.

I had a set of Suzuki mags which comes on the GS1100E that is meant to have tubes installed and these wheels have very small bead surfaces inside the rim with no inner 'lip' on the edge. I installed metal valve stems into them and mounted a pr. of Metzeler tires and they held-up well,the metal valve stem had a slow leak,which was a problem;I had never considered what would happen if I was to lose All the air in the tire at once.. although that rarely happens.
« Last Edit: March 16, 2023, 09:23:36 AM by grcamna2 »
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
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Offline 70CB750

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Re: CB750 K3F - AKA The Red
« Reply #503 on: March 16, 2023, 04:24:44 AM »
I never compared tube and tubeless Comstars but I believe the only difference is the valve.  The rim is pretty deep, it actually takes some effort to unseat the bead.
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline grcamna2

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Re: CB750 K3F - AKA The Red
« Reply #504 on: March 16, 2023, 09:21:04 AM »
I never compared tube and tubeless Comstars but I believe the only difference is the valve.  The rim is pretty deep, it actually takes some effort to unseat the bead.

I remember drilling-out and chamfering a valve stem hole on one of my non-tubeless tire aluminum wheels in the past;to accept a larger O.D. and better sealing rubber valve stem...  ::) I hope it hasn't caused anyone problems.
« Last Edit: March 16, 2023, 09:27:22 AM by grcamna2 »
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.