[samtheman1027]

Hey guys I recently acquired my Father-in-laws 1970 cb350 from his shed. My plans are to fully restore it to how he bought it in 1972. I have a confusing issue with cams/bore/rocker arms that I haven't found an answer for so far. He told me a couple interesting facts about his bike that has me a bit lost. For starters he said it was bored over twice but the marks on the piston heads say 0.75 which i assume to be 3 over standard bore. Is that correct? Also he said that he sent the head off to get port and polished and when he got it back he was having issues installing the cam and rocker arms (he told me he got a new cam). So here is the current situation, I definitely have a skinny cam with the skinny cam gear and i have 2 different rocker arms. Two of them have 8 stamped on the side and the other two are blank, no identification at all. I'm assuming these arms are incorrect for the skinny cam and maybe thats why he was having issues with it? Also one rocker arm is pitted and shows signs of over heating (blue on the pad that rides the cam) and that is also a unmarked rocker arm. I really just need some assistance with how to proceed, do i need a fat cam, or different rocker arms? Any suggestions from the CB gods would be great, thanks!

 

[crazypj]

Going from first to third oversize was relatively common. Maybe it had a partial seizure or something got in and bore wouldn't 'clean up' with second oversize?
I'm not 'up to speed' with the different rocker arms (early vs late) as I haven't even seen 350 rockers for around 16~17 years. I do remember early ones look 'deeper' as the radius or triangle between contacts is shorter (or maybe that's the late one, I forget)

 

[Yendor]

I believe the early rockers have 286 stamped on them vs the newer ones that did not have anything other than a MOLD # (that would be your "8").
Or I could have it backwards and the later ones had 312 but I'm pretty sure it was the early ones that were marked.