Topic: cam lobe and rocker pitting question

[BPellerine]

I can sell this cam , but Have to confirm  that it is an F cam.

I think I am having trouble recognising it because Ibhad one with very noticeably fat  lobes.. I was surprised.
 Pretty sure I checked the end and body for names or numbers, but its starting to look like it was maybe a hotter cam that I let go a few years back.
 Where are you located?

put up some pics of the f cam frank,I have one and may be able to see if it is the same,mine is a known f2/f3.bill

[PeWe]

Good oil supply and don't tighten up the clearance on the big cams.. helps get oil in there.
 One of mine runs 12 thou clearance.

I have started to see this different after install of a DP315 cam with much more lash. More lash must give better chance for oil to lube the lobes.
Before was less lash good for higher lift and more duration. I thought that more lash on EX gave longer time sitting in the seat cooling down the valve. Find the good mix.

My wide eared hard welded cam marked Megacycle and JMR need good rockers...?

[HondaMan]

Honda's cams are/were all Parkerized when new: this polishes itself to meet the rocker feet. It looks like a soft grey coating on the lobe surface (actually it is on the whole surface, including the bearing areas). This is common with IC engine cams and crank journals: Ford began in the 1890s to use babbit bearings on rough Parkerized crank bearings (according to their book, "Ford: the first 100 years") to make them wear in to match each other, with a zero clearance at their beginning. This wore itself to become approximately 0.0010" clearance per inch of journal diameter, which over time became Detroit's go-to number for most engines. This wasn't ALL good: when the crank bearings later came out in polished form, they really needed less than this clearance to start out: Honda did exactly this when their multi-cylinder experimental racing bikes appeared, and this became the bottom end of the Honda 750 and their mini-cars by the mid-1960s designs.

In my long experiments with the 750 I have found that using, for example, 0.0004" to 0.0008" bearing clearance AFTER the engine has been run-in for a good time (maybe 10k miles or more) then causes the engine to be silky-smooth, quieter, and noticeably stronger.

And...removing the little 5mm bolts from the rocker shafts will allow the rockers and shafts to last much longer and there will be noticeably more torque at freeway speeds after the engine has heated up: normally this power melts away then, instead. The trade-off is: if you ride behind a fairing, there will be an increase in top-end noise reflected into your face from the slight ticking of the shafts in the rocker towers.

[754]

Here is a pic of the 4 bumps on the cam.
 And the lobes.  They measure about 1.405 and 1.420

[BPellerine]

looks exactly like my f2/f3 cam frank,I did not take notice of the bumps before.bill

[HondaMan]

The same argument can be made for running soft on soft as hard on hard. The real argument is running materials together with similar chemistry and like hardness will usually gall.

It appears that Honda may nitride or apply some surface treatment to some of their cams and apply flash hard chrome to the rocker faces. I have seen the hard chrome peeling from the rocker faces. And you can usually see the layered material when a rocker is worn through to the substrate.

The 750's rocker foot is hardened after polishing, and originally were also Parkerized until the K4, when they were just polished after that. None were nitrided that I have ever seen? The cams in the K0-K2 (and some K3) bikes were certainly harder than in the later bikes, and the later cams wear considerably faster than the early ones in that regard. This is where the "stepped" edges, like the one described above, show up.