[cbrkid88]

i have a 2002 cbr 600f4i...if i unbolt the muffler and just run a straight header can it hurt my motor at all?

 

[CB750F]

Yes. You would need to have your fuel injection system calibrated for the open pipe. Most likely you'll loose power too. Why not look into an aftermarket canister that's louder than stock but still road legal?

 

[cbrkid88]

yea...well i just dont wanna spend the couple hundred dollars on a new pipe...and it sounded good without the mufler...lol...so idk

 

[CB750F]

It can harm it without the muffler. Not to mention your neighbors will hate you and every local cop will pull you over. Not a good idea.

 

[cbrkid88]

just out of curiosity...how can it harm the motor?

 

[CB750F]

With very very little to no backpressure your header can over scavange the cylinders on the exaust stroke (there is always a little bit of exaust gases left in the cylinder) and cause a lean condition (not enough fuel) which can burn pistons. You can do it if you richen up the fuel curve.

Also,you have to have some backpressure or it can harm the exaust valves, though possibly not in this case but why risk it? What happens is cold air can come up the header tube From the piston's downward stroke after the exaust stroke before the exaust valave is shut and the air can come in contact with the red hot exaust valve and crack it.



Running an open exaust, you could loose power instead of gaining it or move the peak power further up in the powerband where it wouldn't be as useable.

 

[cbrkid88]

ok...i get what ur sayin...now do u mean buy the fuel curve by using a higher octane?...

 

[CB750F]

No you'll probably have to have a tuner or aftermarket controler for the fuel injection (I think yours is injected) to richen it up. It (the ECM, computer, controler...... whatever) MAY compensate for the open exaust but I don't know. It's still not a good idea IMO.

Hunt around on Ebay for a used canister muffler for it. Then it's no headache and you're still legal.

 

[adrian]

It is a really bad idea to run an open exhaust on your f4i. Your bike will end up with less power, shorter motor life (top end), you will probably burn your plastics (fairings), and annoy the hell out of everyone around you with a motor that is going to sound like ****. Save your pennies and buy a used can on ebay. I don't know of any cans for the f4i that absolutely necessitate a fuel management system, if money is the issue.

 

[cbrkid88]

ok...thanks all...i was just getting some input about it...the stock pipe is back on even though its snowing here and the riding season is over but all the plastic is off and getting painted this winter

 

[BillTheCat]

Shop around here on Creagslist I can find good used parts cheep and there is always ebay for a used can.

 

[bac1023]

Yes. You would need to have your fuel injection system calibrated for the open pipe. Most likely you'll loose power too. Why not look into an aftermarket canister that's louder than stock but still road legal?

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