VFR1200 mods

Dips in the midrange are a typical characteristic of all V4 engines. You can't get rid of that without sacrificing a lot of top end power. Basically you would be moving the dip up there instead. It's really a function of exhaust design more than anything else. Aftermarket systems have never really been able to produce big gains on the V4's for that reason.

 

I wonder what removing the cat would do to the powerband?

 

there are very few full exhausts ever made for v4 bikes.
theres that super rare left hand exit 2bros.
and theyre now making full exhausts for the rsv4, because its a rr bike.

i would be really surprized if they ever make one for the 1200.

 

Help the engine breathe if done properly. It has a reasonably good header on it IMO. It does not use equal length primaries but you can't tell it by looking at the Power Commander tuned dyno sheet. There's zero HP dip after tuning with a slip-on.

I want to keep the gas speed high so two 1.5 OD tubes merged into a 1.7 " custom built merge collector " should fit inside a hollowed cat converter. The merge collector needs be built on site while the top 1/2 of converter is open for tight fit. Of course building a merge collector with the converter removed is doable . Adds to adjusting for alignment problems though. Nothing that can't be overcome.

FWIW i bought the Arrow Race-Tech exhaust for mine because it gradually steps up in size after the collector exit helping to keep gas speed high. The Arrow.Italy site has a diagram of it. With the DB killer removed it's pretty loud up top. Sounds cool.

 

cat

2010 Honda VFR1200F OEM Parts, 2010 Honda VFR1200F OEM Motorcycle Parts - BikeBandit.com
A diagram of the exhaust. You think the cat is located where the 3 pipes merge into one? What if one opened that up and removed the innards? You think the cat provides a lot of silencing effect? Maybe even sell the platinum to a metal scraps yard?

 

Silencing effect ,no doubt to some extent along with "some" back pressure .

Anyway, look close on the bike and you'll see it's two, not three pipes entering the converter. Those are the secondary pipes after the primaries have been merged together. The secondary pipe for the rear two cylinders have a accelerator bomb that 6 inches or so long and the front secondary has another thats aprox 2 inches long right before the converter inlet and yet another on the exit tube after the converter. Gut the converter if you want and create a gas swell in the system that may or may not hurt power. For the most part, the swell is there kinda sorta to begin with so i really don't know, but likelyhood to lower overall power from just gutting it is probably slim as a guess.

My vote is to go the extra step and build a true, 2-1 merge collector to install either inside the gutted converter, or in place of it in effort to make even more power. I want to keep the gas speed up without jacking with the wave tuning. The intermediate pipe on my Arrow exhaust is sized and steps up with the same wave tuning in mind . I believe the Akrapovic secondary is similar.