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Discussion Starter #1
I reassembled the cylinder head on my K2 engine today and it all went well but I have a question about the in-head cam chain guide rollers. The centre-roller in the crankcase mouth was hardened and a little chewed so I ordered a replacement and this is quite flexible/resilient by comparison. The ones in the head are smooth and appear to be largely unworn but are much harder (though they will just about deform with a fingernail and spring back) The same thing with the tensioner roller.

CMS has the replacements but I'm pretty shocked at the price - $662 (£500) including shipping for the tensioner and guide assemblies.

Are these parts a regular replacement on an these bikes? I already replaced the stem seals, damper rings and adjuster 'O' rings but I hadn't budgeted for these other parts.

My apologies if I seem to be a needy member. I'm fairly proficient when it comes to engines but I'm just trying to get oriented with these older Hondas.
 

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Mickey, you really need to put your bike model in your signature so people don't have to guess what you're working on. That said, the guides/rollers aren't replaced as often on the 450 as some other twins, but the biggest concern is the hardness of the rubber as it will eventually begin to break apart. I found an engine with far less miles on it than mine and was able to use the guides and rollers from it on my rebuild, but many of the used ones on eBay are as old and hard as ours... if you search long enough you'll find others selling NOS guides, but they're not in large supply out there. Did you look at David Silver as well?
 

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They were pretty stiff and hard back in the 70s they are not soft rubber. They are some composite I believe.

Sent from my SM-J320V using Tapatalk
 

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Discussion Starter #4 (Edited)
I've added my bike to the signature. I tried to do this when I first registered but the system would not allow me and I just looked again and it now does. I found out that you have to make 10 posts before you can add this.

Nothing on David Silver and I'm thinking that most used ones will have deteriorated to some extent given the age. There's a large bike show near to me at Stafford at the end of next month so I'll see what turns up there. There's been a turnaround with CB450s over here in the UK. The price has climbed steeply so most bikes are now sold as complete projects, no matter how rough or incomplete, instead of being broken so good used parts aren't as easy to find.

I'd like to see a NOS part to compare the hardness. The new centre roller I have may be more flexible (and perhaps unrepresentative) because it's a brand-new CMS aftermarket part - the OEM ones are no longer available. All the parts I've looked at on Ebay are in poor condition compared with my own.
 
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