Topic: Cam gear plastic inserts?

[Jhelgesen]

I'm rebuilding the top end on my 73 cb350f, and have replaced the head and cam due to wear.  The factory cam gear has plastic inserts molded into the side of the gear, while the replacement I found looks like aftermarket.  it's got no plastic, but has lines scribed for alignment.

What is the purpose of the plastic, and should I just reuse the old factor gear?

[754]

You wore out a cam sprocket ?

[Jhelgesen]

Cam and rockers were pitted, gear looks okay. Engine sat for a few decades.

Low mile replacement cam on ebay has a plain gear.

[strynboen]

think the "plastic" are for less rattling thain..noise damping..dont have it on my 400 four.

[flybox1]

Based on your VIN, you might have a '72.
Per CMSNL, those plastic insert sprockets  were used "up to serial number: 1055784"  (only the first 55k+ bikes)
(they are still available)
All 350F cam sprockets after that did not have the inserts.

http://www.cmsnl.com/honda-cb350ffour-1972-usa_model435/14321354000-sprocket-cam_14321333000/#.VkzsiaRViko

[jonda500]

I also believe they are only there for cam chain noise dampening, no other reason. They disintegrated in one of my 500's - I found all the pieces in the sump, removed them and chipped the rest off the sprocket - it still runs fine with no excessive cam chain noise.
If you have a new cam chain, I would use the new sprocket, John