Bolt on power

I have heard about changing rear mufflers for "bolt on power" and am wondering about the truth of the matter. Just got a 2000 model DRZ400E with the stock pipe, and has the restrictors removed but spark arrestor is retained. How much perceivable power increase would I see with another muffler.

Ps. Motor still standard (1200KLM).

Its HOT downunder.

It's not hot in Melbourne!

We haven't hit 30 degress yet!


A bunch. You touched on a interesting word "perceivable". My perception is that there was "a bunch" of new power from the T-4 over the stock pipe drilled. Don't know if it was, but, it sure felt like it.

I put on a Big Gun full pipe and jetted it. I then put it on a dyno and did some more jetting and got it up to 39.9 bhp @ rear wheel with a street tire. I then put on a stock pipe with the end cap bored out and it made 41.1 bhp with no jetting changes or anything else changed. I have since run it this way and find it as good or better and others that have ridden it before and after agree that the stock pipe feels better. I think the thing about the aftermarket pipes is the noise makes you think you are going faster. I did over 20 dyno runs in all to test and tune. I just wish it weren't so because I do like some exhaust noise and the stock pipe weighs a ton. I have contacted Big Gun about this and they were not very helpful.

Thanks guys,

just as I thought. Predicted to be 36 deg c plus at Dubbo. :)

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