Performance upgrades.

[1985CB450_imp]

Sure the cams didn't make a lot of power... for now.

Like any other engine build- it's a game of finding and removing whatever the current cork is.

Meaning- the cams may very well be capable of more- once I 'fix' something else.

Could I have put in more aggressive cams? Sure. Would I have lost low end? Probably. Did I want to do that? No- So what I chose is what is appropriate for my goals.

Any gain- without a loss- is a win.

And yea....I'm sure I can still find more power out of this bike.

I didn't start this- you did. So moving on....

Hopefully the mods will respectfully let me set the record straight.

First, you asked what other retro makes equivalent power to your modified CB1100. I replied the z900RS as it not only makes more power but it’s also a retro bike. The revel of retro is debatable yea but I’ve seen all the mags call it a retro and it’s been in a bunch of retro magazine shootouts so I fell pretty safe calling it what it is and that’s a retro.

Second, I don’t use PM’s as the mods can verify and have never sent one prior to responding to you. Your messaged me about how your bike makes xxx torque down low and how the Z900RS is gonna need to downshift to catch you…blah blah blah. You don’t ride a performance bike or drive a performance car in high gear at low rpm, at least I don’t and no one I know personally does. Granted the CB1100 is ideally suited to such but I don’t really consider it a performance bike. If you need a downshift to accelerate quickly you are simply in the wrong gear.

Third, dynos are very subjective. Comparing your specific dyno numbers with numbers out of of a magizine are absurd. Relative humidity, atmosphere pressure, ambient temperature, elevation…..ect all make a huge difference in performance. As someone who has spent the last 25+ years flying jets for a living I know performance data, a takeoff out of Las Vegas at 110 degrees is much different vs Chicago at 50 degrees. All factors mentioned above apply not to mention the varying tolerances between the actual dynos themselves. A dyno is a great tool to measure differences between changes on the same day under the same conditions. Anything else is foolishness.

Last, as someone who has done at least a dozen cam swaps between cars and bikes I was simply stating a fact that I have learned first hand. At 9.5-1 the CB is not suited to run any cam at 220 degrees duration @.050 or greater. Ask any reputable engine builder and they will tell you the same. The longer you hold the valves open the more compression you need. Desktop dyno is a great tool to evaluate static vs dynamic compression. As camshaft duration increases dynamic compression decreases as it’s based on when the intake valve closes as the cylinder can’t make pressure until the intake closes. If dynamic goes too low due to too much duration the engine will suffer poor low end performance but wil be less prone to detonate. On the other hand high dynamic compression will build cylinder pressure early and give good low end but the engine will be more prone to detonate especially at high load low rpm conditions. This is why static compression must be matched with the cams duration for optimal performance.

If you want to respectfully rebuke anything I’ve said please do. If not good luck with your endeavors