Slip-Ons, PC IIIs and Other BS
 

OK, only until recently, I thought that I could just pick out any aftermarket slip on exhaust (for any bike) and dump it onto my bike.

Questions:

1 ) Say company X builds a slip-on model Y for a CBR900RR. It also builds that same model Y for an R1 for example... what is the diference between them? Couldnt I just switch them successfully without remapping on PCIII etc?

2) A lot of people remove their stock exhaust and replace it with a slip on without any PCIII or rejetting, etc... are they wrong in doing this? why and what's the problem?

3) PCIII sounds more interesting for someone that is ALWAYS making changes to the in and out flow of air on the bike... wouldnt a trip to the shop to recalibrate the jets after instalation be the same, and turn out cheaper if you only do it once? (air filter and slip on)

feel free to discuss any other on topic issues :icon_urinal:

1, I'm pretty sure you would have a tough time putting a 2005 1000rr exhaust on an f4i, because it won't fit right. The exhaust won’t work because of the mid pipe. Plus the design of the bike is different. But, If you like to fabricate, I’m sure it can be done.
2, You can get away with a slip on without a pc3... You wont hurt the bike.
3, All a pc3 does is change fuel ratios via throttle position.

hope this helps

So, The only diference between the various (bike specific) Slip ons is only the "fitment kit"? there's no specific study other than position on the bike when a slip on is created? the natural air flow of the bike doesnt get taken into account?

Also, I've noticed that if I twist the trottle just a little and let it climb slowly, there are 2 peaks in power. My 929 jumps at around 3500 (like I twisted the throttle a little harder) and once again (major power surge at 7000) though i suspect thats to do with that flapper valve business that i've been reading about... Would this be normal, or does it suggest that the jetting is off?

1) it usually is bike specific, because my exhaust on my 954 won't fit on my wife's gs500, or my f3, or an r1. then there are bolt-ons and slip-ons for different bikes. it all depends.

2) depends. if the exhaust has too little backpressure (like a gp pipe, or just headers (for example)), it will lean your bike out to the point that you'll burn up your vavles when riding the bike really hard and cause serious damage. for most bolt-ons/slip-ons and just cruising around town, it would take a very long time to do any sort of damage to the bike. however, you won't make any more hp, if anything, you'll make less. the best way to go is get a PC and a filter first, then a pipe.

3) our bikes are fuel injected that use the power commander, so there are no jets. you can't just recallibrate the ECU (which is what does the job that the jets do on older carb bikes), you'd have to replace it with one thats programmed for your bike's modifications. what the PC does, is it interrupts the communication between the ECU to the throttle bodies. thats why when looking at the fuel table on the power commander software, you see numerical values added and taken away from the stock ECU's fuel table. the ECU talks to the PC, the PC changes the ECU's signal with what you've programmed into that specific map and then communicates it to the throttle bodies.

go look at some Air/Fuel ratios of carb bikes, and bikes with no PC that have some mods. then look at the A/F ratios of bikes that have had a custom map tune with a power commander. you'll see how much more consistent the A/F ratio is on the bike with the custom map. and a custom map tune costs just about as much as taking a bike down to the shop to replace the jets


hope this helps

You can add a PIII to a stock bike w/ a stock pipe n get it dyno-tuned n still get an improvement ;)