Hi Rick,
I read in your last post :
When you order a hard weld cam you are getting a cam that has the lobes welded by hand and ground to the correct profile. A hard weld cam is hardly an old cam, but is a rebuilt cam that is much better than the stock cam ever was. Hard weld cams last longer than any cam you can use and have less parasitic drag than billet cams so make more power as well. The cams we sell have a much better profile than the stock cam and is the best cam available at any price.
The webcams and megacycle cams are not bad at all, and I never said that. Yes I now a few horror story's about these cams (broken cams while riding fast), but I also hear good story's too (from the same guys).
Older cams (especially relative long cams) are most prone to fatigue if not destroyed buy wear. I don't know what your knowledge is about metallurgy, but I'll try to explain a few things. A cam is soft (flexible) on the inside, and very hard on the outside. This hardened part is very hard, but very thin too (a few hundreds / tenth of a millimeter. This hardening is done by heat treatment or / and chemical processes like nitrating or chroming.
It's not very difficult to make the whole cam hard, but if this was the case, it would brake as easily as glass or from fatigue. A very thin layer and a soft core makes a cam AND hard on the outside AND flexible inside.
If you look at your cam, you will see that the rocker is worn down through the thin hard layer into the soft material,
Once this layer is gone, wear wil go fast (because of the soft material).
Why does this layer disappear ? Bad oil, but that is something completely different, a subject for an oil debate.
Sticking to the cam, as I mentioned, heat treatment is also a hardening method. If you weld on a cam, it is a heat treatment, but to weld the complete cam you have to put a lot of heat in it. Everyone knows that a welded piece of steel will not break directly on the weld, but clos to it.
If the heat treatment after welding is not done properly, the inner (core) of the came is not soft and elastic any more, and that's the reason that these cams tent to brake or that parts of the cam lob break out.
This heat treatment is a very difficult process, and the process parameters are depending on the type of camshaft.
Next to that, the core has a long history before it's welded, maybe it has done 50.000 to 80.000 mile before welding up and grinding to the correct cam shape. Fatigue plays a big role in the cam, and since the cam has this history, nobody knows how far that process is (X-ray scanning can make it visible, but not just before it will break).
Heat treatment can repair the process that lead to fatigue, but, like I said, this is a very difficult process. When money plays a role, I'm not certain if this heat treatment of these weld-up cams is done properly.
This is the reason why I prefer a NOS original camshaft, but that doesn't mean that a welded up cam is bad. Next to that, I don't like spending money on re-jetting because the cam has a different shape, I like it keep it as close to original.
If an NOS camshaft has the same price as a megacycle cam or webcam, I would choose a NOS original cam, if a NOS camshaft is unobtainable or way to expensive I would go for a welded-up cam. Inform yourself about the prices and process, also inform yourself about the cam shape.
Remember, in original condition, the performance is good, for track and road race you could buy a wilder camshaft, that's up to you.
About using other air filters like K&N I have a few points.
First of all, I hear from different people that a CB400F without a filter box is difficult to re-jet, but you have to ask around, I think that on this forum there are a few people who can tell you how to do it.
Secondly, and that's the most important point, an air filter should filter the air, and should do that good.
Bigger particles are not a problem, but small particles are. Be sure that the replacement filters are just as good as the original filter (smallest size that can be filtered out).
From my point of view, that is not the case at the moment.
Jensen
