My PAIR Blockoff experience - 07 CBR600RR
 

I know this is a topic of great contention, with claims ranging from "OMG I ADDED +97 HP HAHA LOL" all the way to "This mod is bad, and you should feel bad." As such, I'm posting my personal experience with it, to add to the average.

For info on the specific equipment\mods I'm running, see my sig.

Stock, this bike had an annoying boost in power around 4k. This sucked when turning from a dead stop, as you'd get this jolt right in the middle of your lean. Adding the Yosh RS5 slip-on mellowed it out a bit. Not a ton, but enough to be noticeable. I ended up doing the PAIR blockoff because I had the airbox out anyway to do some repairs to the front end after an endo, so I figured "why not?" The plates were liks $25, and showed up in a few days.

**MAKE SURE YOU GET PLATES WITH DIVOTS FOR THE REED VALVE SCREWS.**

Some blockoff plates are manufactured with the assumption that you're going to remove the reed valves completely. There is no need for this if you get the plates that have notches drilled into them for the screws that stick out on top of the reeds. Driven brand plates have these divots; a LOT of other mfgr's DON'T. Make sure you look. Also make sure your blockoff kit comes with something to block off the airbox intake that you're removing the hose from, so as to maintain vacuum pressure, or you'll get an FI blink and the bike will run like crap.

WHEN DISASSEMBLING: Make note of every single hose and sensor you disconnect.

WHEN REASSEMBLING: MAKE SURE NONE OF YOUR HOSES ARE KINKED, and make sure you reconnect every single hose and sensor. Any change in vacuum will trip your MAP sensor. In fact, the tiny hose that plugs in below the MAP sensor (under the airbox, seat-side) is VERY hard to get back in without kinking it.


My personal performance experience: The "jolt" around 4k is nearly nonexistent now, without a loss of power. I know no power is lost as I don't find myself having to add more throttle or lean less than normal when turning from a dead stop, or ever. The bike doesn't jump at 4k anymore, which I like a lot. You may not. This is all subjective. I also noticed the engine has a bit more "growl" to it, which again I like, and you may not. I noticed no performance gain, except that slight boost under 4k that smoothed out initial acceleration. All of these findings may be from a combination of ALL my mods, so you may find none of these results apply to you if all you do is the PAIR blockoff.

I would very much like to dyno my bike and get a "real" map made for my PCV, but for now, this is all I can give you guys. It may be completely irrelevant to anyone but me, but there it is.

I have the driven plates as well, I and they did not come with the holes predrilled. I installed them not knowing I had to remove the reed valves. For anyone else who might think of doing this the sound that it makes is close to an exhaust leak or even piston slap. I sent driven kit back and they sent the kit with the holes drilled.

I did the mod because I wanted more room to work under the airbox, I was dropping as much useless weight as possible and the main reason: It makes tuning a carb'ed bike easier, the A/F ratio will be more accurate and the powerband smoother. I cannot comment on a FI'ed Motorcycle however, I have not found any negatives to doing this mod.

Bike: CBR600 F4
Factory Pro Race (Stage 3) Jet Kit
Ignition Advancer
Manual CCT
BMC Race Air Filter
Driven Block-Off Plates
Leo Vince SBK Full System / Jardine RT-1 w/ micron serpent headers.
Secondary Air System Removed
Plus more in a link in my sig.

I can definitely see this being a huge help with tuning carbs. Great point. Also, the sound is very much like a small exhaust leak near the header, but not as much on the high-end, "airy" sound.

agreed on the sound.