Any cam chain tensioner replacements?

[Rgmack]

I've got a '79 CB650 that I'm doing a rebuild on. I noticed the cam chain slipper and guide look like they're beginning to break down. They're developing cracks and I assume that'll lead to chipping and bits of plastic getting chewed up by my motor. Both parts are obsolete. I've looked at all the usual sites, vintagecb750, David Silver Spares and House of Honda Parts and can't find them. I've seen used ones on eBay but they have the same cracks that I'm worried about. Are the cracks even worth worrying about? Is there any other site I should try? Do any of the other CB's use a similar part that may not share the same part number but work?

[Folsoml]

There is a gentleman named Brent on the DOHC Custom forum that makes tensioners for the DOHC Hondas. I don't know if he does or can make them for the CB650, but you can email him at:

brentmopar-at-xtra.co.nz

[Volker_P]

I would think you won't be able to find chain guides or tensioners without any cracks in the plastic part any more.
So the question rather is whether this is a problem.

If everything still sticks together and no large parts are missing it should be no problem.
If you already have several parts that you can identify as tensioner plastic parts in your oil pan, things get different.

And of course the chain guide should not look like this one: viewtopic.php?f=2&t=8052&p=61176#p61398
The tensioner shown there below also has many cracks for my taste but I would not think it should fall apart immediately.
You probably won't get one without a few of these cracks so one may even reuse this one without running into a problem.

One may have different opinions how many cracks are tolerable but the really crucial issue is that the side rims still exist on their full original length.

BTW, someone made his own guide, so probably really without cracks:
viewtopic.php?f=4&t=9136&p=63994