Topic: What aftermarket camshafts work with stock rockers (CB750K2)?

[gschuld]

So let’s take a NOS genuine RC engineering cam (RC 327) from the 70s.  It’s not hardwelded, but cut from aftermarket CW blanks from the period.  The lobes on these are considered “soft” like the factory OEM cams?  They should work perfectly with a fresh set of NOS OEM rockers yes?  Since that is how they were originally used.  Are hardwelded rockers any particular benefit here.

How about a mint condition ( VERY minimal usage, lobes not even fully shiny and broken in yet) vintage performance cam (another genuine 70s RC327 cam for example) made from an aftermarket CW blank?  What would be best to match with it?

Great condition used LOW mileage rockers that appear perfect in every way.
NOS OEM rockers
Hardweld rockers

Take the same questions and now swap in beehive springs in place of the standard aftermarket high performance springs.  The much lower spring pressures of the beehive springs can only be a help regarding cam lobe/rocker wear.  Does this affect the answer?

George

[PeWe]

Nice! It's a pity though, that you can buy a cam for 250 bucks, then have to fork out another 800 for rockers, once upon a time I could buy a running CB750 for that much......

I have used that welded cam with stock rockers one summer. But I might install better rockers I need rockers as spares for my K2 engine or the K1 bottom....Take them from my K6...
For the long run welded rockers would be fine. 

A friend here told me that old RC cams could be rather soft. He used them for dragrace. Maybe a short period?
Softer springs must make a difference on the wear.
I heard that Kibblewhite 5mm valve kit use softer springs compared with the old race springs I had for stock stemmed valves.
A good oil.....

[BPellerine]

not saying one way or the other,but I bet there were and are alot of bikes running around with stock rockers,high dollar race motors may be another thing though,I have a few aftermarket used cams,including a couple of 315s,none were in motors that had an adjustable sprocket let alone hardweld rockers,so things must have been diff back then.bill

[Terry in Australia]

Yeah, I think that in a perfect world where money's no object hard welded (or even just new OEM) rockers are a good idea, but in the real world where street riders are mostly riding well within their speed limits with just the odd high RPM squirt occasionally,  good used rockers are fine, and of course, after 40(+) years of operation, they've all been "work hardened", just like most of the other internal components anyway. I say just keep nice fresh oil up to them and if your old rockers wear out, well, buy some more.

[HondaMan]

not saying one way or the other,but I bet there were and are alot of bikes running around with stock rockers,high dollar race motors may be another thing though,I have a few aftermarket used cams,including a couple of 315s,none were in motors that had an adjustable sprocket let alone hardweld rockers,so things must have been diff back then.bill

I think you're right: I've installed only Megacycle cams (except 2) in the last 9 years, if not stock, and they drop right in, wasting the $$ I spent for their adjustable sprockets. After the 3rd one: now I try it first, and if needed then apply the fancy sprocket. The others: one was a CX3, one was a Dynoman, both had to be offset several degrees to reach specs.

[PeWe]

We need more old success stories about hot cams and stock rockers. Bad rockers can be caused by bad/wrong oil or pitted cam lobes.

I read somewhere that Honda cams were cast almost exact, just a little grinding needed and inclususion lures under the surface that can open up and damage the rockers. So holes in the cam lobes might not be rust.

Oil threads are needed since there are modern oils with not sufficient lubrication of cam/rockers. I have felt huge difference between oils by how my gearbox feels. It must affect the cam and rockers too when gearbox feels very hard and mechanical. Forget to find neutral when warm. That kind of oil must be a rocker/cam killer as I see it.

My Megacycle welded cam will get welded rockers just for sure and just for that cam, hopefully in a package moving my way when I write this.

When searching welded cams/rockers I found a Ducati thread were Ducatis between 1995-2003 something had preworn rockers after not many miles. Probably due to bad hard chrome process at the manufacturer. Oil with its flow was mentioned too.