I believe the first thing you want to do (after FCRs) is clean up / open the exhaust ports and then run a slightly bigger pipe, sans the bad collector. The unobtanium spaghetti hears were the ticket.
Has anyone just hogged out a set of heads to see what the performance improvement would be?
If so ,where did you have it done??
It really depends on what your final goal is and how much dinero you're ready to pour into it. For ultimate performance Chris Kelley
recommends the
testarossa head work by Guy Martin. If you go the whole 9 yards, the testarossa head work will cost you a good 3K.
But with split 41 FCRs on short manifolds and 95mm high compression pistons (966 cm3), once everything is properly setup, you should be in the
100+ HP neighborhood. That is pretty much the highest amount of power you can get from an old 900.
Buuut now that the new 800, 1000 and 1100 2V engines have come out it might not be worth it to dump all that money into the bike. Brad Black has a good comparison of the different engines
on his site. Essentially, for an engine build from the ground up, it's better to start with a 1000 (or 1100), put in a big-bore high-comp kit and then move forward from there to get the most bang for your buck.
The most surprising of Brad's discoveries is that the stock headers aren't that bad. They flow pretty well, and the 'X' section helps get more power at higher RPMs vs two individual pipes.
Bigger is better, but only to a certain point. The bigger the pipes are, the slower the exhaust gas moves, and when it's too slow the heads will not fully empty themselves of exhaust gas, meaning that less fresh mixture will go in. Which is a bad, bad thing!
Me? I'm a cheap bastard!
The less I can spend on an engine, the better. I'd like to get my hands on a 1000+ engine, possibly from a Hyper or an old Multi since the cases are already narrow for the SBK swingarm. But that would mean getting and tuning a TCIP box to run the engine off carbs. So a 900 might work out better for me.. but that's for another thread
