Author Topic: CB550 Camshaft Sprocket Damaged?  (Read 2221 times)

Offline Neilw

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CB550 Camshaft Sprocket Damaged?
« on: July 31, 2026, 10:16:24 AM »
Hi,

Just got round to fitting the top of the engine, and as I was fitting the camshaft sprocket, a bit of hard plastic flaked off. On examination, a larger bit had previously come off, and I can see there is a small crack in the plastic on the reverse side.  The rest of the plastic and sprocket is fine, but it is clearly a weak point.

Are there replacement parts available, as a quick look suggests they are not easily found? I guess secondhand sprockets would have the same age-related weak point! OR could / should I just chip off the loose bits and reuse the existing sprocket?

Seems to be one step forward, two backwards with this bike :-) lol

Thanks for your wisdom and help.

CB550 1978 F2
« Last Edit: July 31, 2026, 10:19:28 AM by Neilw »

Offline Johnwebley

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #1 on: July 31, 2026, 01:18:15 PM »
My thoughts are sometimes in the past a PO has had problems refitting the chain and used a screw driver to lever it on,

Obviously a better condition sprocket would be ideal,

But you could tidy up the broken ends using a file,radius the sharp edges, and refit

The plastic looks secure, so shouldn't be an issue.

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Offline McCabe-Thiele (Ted)

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #2 on: July 31, 2026, 02:08:11 PM »
I remember when I was fitting my new camchain on my 500 it took me a while to work out the correct assembly order to avoid  using a lever to get the chain in place.
Iirc Ken advised me how to do it, one of those things thats difficult to understand from a manual.

My struggle is documented on P40 of my 500K1 project - link on my rebuild below.
« Last Edit: July 31, 2026, 02:17:14 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Oddjob

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #3 on: July 31, 2026, 02:10:40 PM »
The shroud was fitted IIRC to stop the sprocket resonating, as in making a ringing noise. A small piece missing will do nothing detrimental IMO. Same applies to the front drive sprocket on a lot of bikes.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Neilw

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #4 on: July 31, 2026, 04:31:36 PM »
Thank you all; it confirms what I was hoping for.

I've spent 6 hrs today fitting the chain to the sprocket - it's driven me mad, and I avoided using tools to prise it on. Another difficult aspect was getting the sprocket seated on the cam after I had the chain on - this took a few hours of fiddling - eventually I eased it on using the fixing bolts. All done now!

Offline McCabe-Thiele (Ted)

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #5 on: July 31, 2026, 06:00:50 PM »
Well done Neil, they are fiddly, I was always mindful not to drop a sprocket fixing bolt into the engine when I did mine.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Neilw

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Re: CB550 Camshaft Sprocket Damaged?
« Reply #6 on: July 31, 2026, 09:37:57 PM »
Well done Neil, they are fiddly, I was always mindful not to drop a sprocket fixing bolt into the engine when I did mine.

Same.  I have perfected the art of dropping something and it just disappearing on the floor. I hate to think of the number of hours I've wasted looking for springs, nuts and bolts. I'm taking up a new sport - magnet fishing!