185/200 cam questions. Again.

[jsimonh]

I have found on this website that the xr200 cams and the xl185s cams are a little "hotter" than the stock 200x cam. So I ordered the xl185s cam from hondaline for 51.00 dollars plus 8 for shiping :D . Then I stumbled across this: http://www-staff.lboro.ac.uk/~elvpc/bikes.html?http://www-staff.lboro.ac.uk/~elvpc/papers/XR200.html
In his chart the numbers for the lobe height are lower than the stock ones in my service manual :eek: . What gives :wondering ? Can anyone clear this up for me :confused: ?

Thanks. :TrikesOwn

[Mobular]

Link no workee!

It's entiely possible tha the lobe height is not as tall. What you are looking for in a performance cam is increased duration and greater lobe center angles. There is where the real gains are made. Don't worry too much about the height, after all you won't have to be concerned with the valves coming into contact with the piston!

[jsimonh]

The link works now, I hope! :D So the lobe height doesn't have as much to do with it as duration and angles? Cool! I was getting worried that the xl185s I just ordered would be not as good as the stock one. That would have sucked :mad: .

[bigredhead]

They are very close... i posted the specs for them a week ago....

[Mobular]

As long as your new cam has a bit more duration, you'll be fine. It all depends on what you are trying to achieve by putting in your new performance piece.
Simply put, the cam is a valve timing device. Stock cams are timed to provide peak power at lower RPMs, while "hot" cams come on at higher RPMs. The idea behind "performance" cams is to ease the breathing process at mid and higher RPM. The longer duration cam will breathe easier the the shorter, same height cam. Obversly, a same duration, but higher lift cam will not perform as well as the first cam. Ideally, a "better" cam has a bit more duration, and slightly more lift. In addition to better cam, you could have larger valves installed, port work done, and a large diameter exhaust system and a larger carb, all to aid in the breathing process.
All this said, there is a trade-off. With increased duration, you will lose some of the bottom end power, not a lot, but there will be some loss. Also, porting, a big carb, and a bigger pipe will kill off more bottom end and fuel economy, but will increase your mid and top end power. On the other side, an stock cam, small carb, and small diameter pipe will give you good fuel economy, very good throttle response and an engine that will like to run all day at lower rpms. It all depends on what you want to do!