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Forks/brakes: CB vs CL

2236 Views 6 Replies 4 Participants Last post by  66Sprint
I'm in the market for a new front wheel for my '72 CL450K5. The hub seems to be bent, so it is pretty much trash from what I've gathered. I kind of like the drum brake, but it seems there are more wheels available from the CB series, which is probably because the dual-leading-shoe drum is coveted by vintage racers, so I'm willing to make the conversion if it is cheap enough.

A few things I've read suggest that to make the conversion from the drum brake to disc, everything from the front wheel to the triple trees (I'm a little vague as to whether the trees themselves need to be swapped) needs to replaced. Looking at my fork legs (from the CL), I notice that there is an extra bolt hole that is being unused. Using the mounting hole currently occupied by the torque link along with the vestigial mount point, I thought a disc brake caliper would bolt up nicely.

I've finally gotten around to comparing the parts fiches. CMSNL has incomplete parts lists for the front forks of some of the CB and CL models, but the picture for the CB450K5-7 looks exactly like the CL450K5-6.

A link on this site sent me here where I was able to get part numbers.

The left fork assembly for both the CB450K5-7 and the CL450K5-6 is P/N: 51500-323-315

This discovery leads me to believe that all I need to switch from the drum brake setup to a disc brake for my CL450K5 is the wheel, axle(maybe), rotor, caliper, master cylinder, brake line, and lever from a CB450K5-7. No need to mess with the forks at all. I might even be able to grab all of those parts from a SOHC/4 model and still avoid swapping forks, but I haven't quite gotten that far yet.

The front forks for the earlier CB and CL models are obviously different.

Does this sound right to you guys, or have I missed something?
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Sounds correct to me? Try sourcing CB500/550 and 750 parts too. Eventually with enough searching you can get em cheaper than trying to buy stuff specifically for the 450 from a certain year.

Others should chime in here with appropriate years concerning part swapping, soon enough.

Don't forget the brake line pressure switch along with your other lines. While you're at it, you may as well do the dual disk setup... You know you want to!! :cool:

GB :mrgreen:
Something new I just found out. Here is a list of the bikes with the same drum front brake hub as my CL450K5. I'll start looking into hubs from any of these models, including the old CL72 (CL250) CL77 (CL305) Scramblers.


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.... First, How did you bend a hub?...A bent rim I understand.......
Do you mean:
HUB (the central "spool" the spokes connect to the rim),
RIM (the metal loop/ring that the tire mounts on), ......
WHEEL (the whole assembly... Hub, spokes, and rim) ????

And, There ARE differences in the 305 hubs.... (narrower, and only 36 spokes)
the CB 450 ones are wider overall and 40 spokers( usually 18")
The later CL's have the speedo drive built into the brake plate and 19" rims

They can be made to interchange, but are NOT the same..... Steve
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I have a set of wheels off a 73 CL... K6? good condition if you are interested in the front or both we can work something out
Yes, you read correctly, HUB (as in #2 in the diagram below)

I suspect that mine is bent because I notice some lateral (side-to-side) run-out on the hub, itself, along with lateral run-out on the rim. Also, my front brake will pulsate. This was a value added feature that came with the bike :lol:

The original part number for the hub on the CL77: 44601-283-000 According to the fiche on, this was superseded by part number: 44601-292-010 The part number for the CL450 hub: 44601-292-010

I might be mistaken in my understanding of "superseded"; I thought that meant that they made improvements to the part but that it would be a "bolt on" replacement for the previous part. Maybe the newer part can be used but other parts need to be replaced as well (as in, the whole wheel along with the hub)? Or, the fiche is wrong? The list I showed was from and was based on a search for the 44601-292-010 part number.

The speedo drive on my CL450K5 (SN 500XXXX) is on the right side, opposite the brake plate, and it has a 40 spoke 19in wheel.

This hub supposedly came off of a CL72, and it looks to be a 40 spoke hub with the speedo drive on the side opposite the brake plate. I thought that hub might be a good place to start building a wheel using my current speed drive and brake plate, which I'm assuming isn't misshapen, and maybe a new, lighter rim.

I appreciate your feedback, Steve, and would welcome more.
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I've seen bad bearings, or the "pockets" they fit into wallowed out causing "loose" bearings resulting in lateral play, but that usually has a slight vertical component as well as side to side..... Other than that, it seems (to me) that ONLY a undertorqued/mis-spaced axle (allowing the whole wheel to move slightly side to side) could be the cause...... I have a later 450 hub, but no matching brake plate (left, plate contained speedo type) ...I'll check the yard for an early style hub for you.....
It may well be that the 305 HAD 40 spokes (been awhile for me), but the brake shoes were narrower (same radius/diameter though)...The 450 ones WOULD be an upgrade, albeit slight......The early ones do share the same casing for the speedo drive, but I BELIEVE the 305 forks were a couple mm narrower... (again, ancient history)...Bill440cars is the resident 305 afficianado, so I'd trust his opinions on 305 specifics...... It MAY be just a matter of spacing/spacers...
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