Cal thanks for sharing your experience.

What you are seeing is the limits of your current set up, and I cant tell you exactly if its the cam, actual compression ratio, port size or another area that is causing the reduced rev or flow etc.

I had a similar issue with this quad when I first purchased it. It had the 440 kit (actually not a tru 440) and was strong on the bottom end but wouldnt rev to save its life. Top speed wise with stk gearing is was about the same as a stk engine with a silencer. Changing the cam to a stage1 and upping the actuall comp from just below 9:1 to 10.3:1 made a very large difference and the increase was from bottom to top. Now after the last rebuild I went with the stage2 and upped the comp to 12.5:1 and its worlds better again, and still no measureable loss in bottom end.

If you can see that their was an increase in compression to compliment the longer duration of the new cam you can understand how they work together. The compression both made up for any loss in bottom end from the new cam and allowed the engine to rev quicker as well and this made a pretty good overall package.

I will be tearing it down again shortly and besides checking it all out will be installing an even larger cam (Web #479) and though I would love to raise the comp even more to work with the slightly longer duration this cam offers I dont want to push my luck with the stock rod etc. Plus the major increase from this cam will be in lift not duration and that will allow the engine to breathe even better at lower rpms.

For those who dont actually understand all this (those that do please dont take any offense) what happens is that when the engine is turning more slowly or at lower rpms it has more time to keep the valves open (both intake and exhaust) but when it is at higher rpms this time is reduced and unless the duration is increased (one of the benefits of the stage2) there will not be enough time for the engine to take in the amount of fuel/air that it needs because the valves close to soon. This is why the larger cams wwith more duration help the top end.

AS far as the bottom end is concerned that very same increase in duration now causes the valves to be open too long and at lower rpm it can not create the desired amount of torque.

I hope that helps as I am not a cam designer or engineer and have only learned this stuff thru my own needs etc, and I would be more than happy if someone with more knowledge could add to this.