First off, I feel that my bike has been "lacking" lately. I think it's most likely that I am adjusted to the power levels and I need to up the game a little bit.

It's a 1997 CBR900RR and I am thinking of trying something new out. I tried to find more info on this on the forums, but I didn't have much luck. I know the stock air box is made to keep a certain amount of air pressure for the carbs. I wanted to switch over to open element filters which would sit on the top of each carb, 100 octane fuel, rejet the carbs (with some port/polish/knife edge work), along with advancing the ignition to fully gain all advantages of this possible setup. Currently I have a full 2 Bros exhaust, so I think doing this might actually make it possible to bring in some more power if I do this correctly.

I have carb syncing tools so I will be set with that. But when I am messing with the carbs would it be wise to clip on an AFR wideband to keep everything in check? If anyone has done any of this work before and has any tips for making everything work well together please let me know as this will be some-what of a shot in the dark for me. Thanks and lets discuss.

 

there was just a post on open individual filters on this forum, and the setup was strongly discouraged. They do not provide any more power and kill low end power and response. That being said, everything else you want to do will yield power, albeit some of your ideas are very time consuming and expensive. Let me ask you a few questions here; have you rejetted since adding your 2 bros? do you have the stock header? have you ever ported a cylinder head before?

Now here is my take on your plan. For starters porting the head in particular is really not fun or easy to do. I have performed this exercise on a vintage Yamaha and a toyota supra, and its going to cost you about 40-70 hours of time, plus about 500$ to do the job right. And you had better really know what your doing when you go to put the head back together, or you might die when you drop a valve and lock your engine up. If you have that kind of time, money, and know how the end result will be around 10 more ponies and a faster windup. Ignition advancement is a good idea and you can do that with a Dyna 2000 ignition or Factory Pro fixed advancer. That will give you maybe 3 HP and a bit more snap when you hit the throttle. 100 octane fuel won't get you more power but it will prevent detonation if you really advance the timing and/or mill your head for higher compression. All of this stuff might gain you 25 horsepower max, and I am not sure that that's a big enough number to justify the price and time. The 97' is plenty potent, and if its "lacking" then maybe you should move on up to the 1000cc class, then you can skip all this tricky mod work and save yourself the risk of internal engine issues with the head removal. If you want a cheap way to get that zip back in your bike then try getting new sprockets, do down a tooth on the front sprocket and add 2 or three to the back and then tell me that the bike is lacking. Also, the cheapest way to a faster ride is to strip everything off it that you don't need (back seat, stock header, and anything else that is steel or heavy).


If you want more pep at full thottle at a good price then Nitrous Oxide is your best choice. For around 500$ you can get a Sneaky Pete system that is designed to activate when you give the bike full throttle. You had better really be a good rider and know what your doing when that **** hits your intake cause your going to hit warp speed faster than you can blink. A 30HP shot will probably lift the front tire violently enough in 5th gear to put the triple tree through your helmets face shield. But, if its power you want, then that is the cheapest, easiest, and most intimidating way to get it. I rode a nitrous harley about 3 years ago and it is something I will never forget or do again...

Good luck with whatever you do, but make sure that your doing it for the right reason and not just for bragging rights or stop light to stop light racing.

 

Thank you for all of your info. I have decided to rejet the bike and going with the Factory airbox mod with a +4 ignition advance and I will still run 100 octane. After doing this and resyncing the carbs of course, I am hoping for a bit more pep. The bike has already been stripped out and if I am still not liking what I've done with it, then it's time for the next step being another sprocket/chainwheel set. I will most likely spring for the 520 Vortex kit (not sure on the gearing yet), but that should definitely put more bite in the rear end. Aside from that there isn't much more that I will consider doing after this point, so if I am still unhappy - then I guess I don't belong on bikes at all.