Straight Pipes on 84' VFR 500

I am in considering making some straight pipes for my 84'. I'm sure someone here has done something similar. I will have a K&N air filter and a K&N jet kit. Do you think I would have enough back pressure for the optimal performance? Would it be better to leave the expansion chamber and just make straight pipe "slip-ons" or should i cut out the expansion chamber altogether?

Has anyone done anything like this in the past? If so let me know how it panned out and give me some advice, thanks.

 

4 stroke motors don't use expansion chambers, not in the same critical way that a 2 stroke does, futhermore power is not optimized via backpressure, anyone who claims that a motor requires backpressure for optimal performance needs to get their head examined and is likely smoking a little too much crack for their own good.

So here's the deal, what makes a motor work well and why you can't just slap the largest exhaust on that money can buy is an effect called scavenging. Scavening occurs when the exhaust pulse from one cylinder pulls charge from another cylinder out by creating a low pressure area behind the exhaust pulse doing the scavenging. This is why you see many sport bikes using a 4:1 system as opposed to two 2:1 systems, it makes more power because it does a better job of scavenging. The other thing that becomes critical is the primary pipe length and collector design. These are calculated and then dialed in from there, usually the calculations get you more than close enough for OEM apps, but racers find themselves looking for that last 1/2 hp.

Once you decide on the header design, then you get to build, then after all is done, then you get to tune it!

 

Thanks for the info. I think what I am going to do is leave the catalytic converter on there and just replace the stock slip-on mufflers with some tubes of straight pipe. That way I can keep the same stock header design and I can hopefully get the exhaust a little bit more free flowing. I'll put up some pictures on here of whatever I decide to do.