Rejet with new pipe?

well i just purchased a full GYT-R titanium exhaust system for my bike... 04 yz450f

i got the whole system for a steal and was just wondering if a rejet will be in order?

there arent any instructions included so i dont know what to do... or if i can use one of the 2 jets that yamaha gave me when i bought the bike!

well just curious to everyones input.. really want to put the pipe on and to have it run pretty good and not have to tune to much so who knows

thanks... paul

If a pipe does increase performance it will need to be rejetted. Not all pipes do increase horsepower. Install it and see if anything changes, jet to solve whichever problem arises.

anyone else have any experience with a GYT-R pipe install?

would like to know if i have to rejet before going for a ride and wasting a day just to tune :-/

If a pipe does increase performance it will need to be rejetted. Not all pipes do increase horsepower. Install it and see if anything changes, jet to solve whichever problem arises.

To me, this is a common misconception. It's not the pipe itself that increases the horsepower. If the pipe is less restrictive it will enable a more free flowing system, which in turn creates a leaner condition in the motor. To solve that problem, and in turn increase horsepower, more fuel is added to the cylinder through rejetting. I think this holds true for major pipe changes. If, however, the increased performance is merely moving the power around the powerband (not necessarily adding power) than a rejet may not be required. There's a ton of variables and hard to make a statement that holds true all the time. The biggest thing I wanted to get across is that power comes from the fuel....if more fuel is able to be successfully converted to piston movement, then you'll get more power. plain and simple.

anyone else have any experience with a GYT-R pipe install?

would like to know if i have to rejet before going for a ride and wasting a day just to tune :-/

It will depend on many factors - Try it and see how it runs. You may have to raise or lower the clip on the needle jet and/or increase decrease main jet size depending on the symptoms....BTW takes about 10min to do this....

If you do not want to tune it do not use it.....but it will run better once it is tuned correctly.

And tuning is part of keeping 4stroke running at their best...... :banghead:

I put a FMF ti-4 and power bomb header on my 03 yz450f, and i phoned my dealer about tuning it and they hooked it up to a machine and put something in the exhaust and it gave it a perfect reading about what they should adjust and now i have never felt my bike run smoother only took them 30 min to make it perfect.

The machine they used was called an "exhaust gas analyzer". :banghead:

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