2011 crf450

Stock engine. What would be the best pipe for an intermediate rider? Mostly hair scrambles and trail riding. Im looking at a fmf factory 4.1 with mega bomb. Or a yoshimura rs-4. Is there noticeable power gains with a stock engine. When i look at the website for each manufacturer they show a graph but the gains look so small.

Also does the type of material the pipe is manufactured with have any input on power. ss or ti?


Material type has affect on the power.  You're betting off with some good mapping - $50 spent on mapping will give you a better gain that a $600-$1,000 exhaust system.

I also have a 2011 CRF450R. I race A class in hare scrambles, cross country, GP's and enduro etc. I run the stock quiet muffler (the 2011 muffler is under 96 dba) with an aftermarket spark arrestor, nice and quiet.

Currently I am in the process of detuning my bike for long tough races. Coincidently, Barcia just had an interview where he said they were not getting good enough results, so he had to "tame down" his bike a little, so he could hang on to it and keep charging the entire race, instead of fading out at the end. last week he finished 3rd place, guess that helped.

Set up a course with 20 minute lap times, ride it non-stop at race speed, only one minute or less stop for quick fuel pits, run it hard for a full 3 hours (typical offroad race up here). Have someone write down your exact lap times for all 9 laps with a stop watch. Notice how you get tired, and your lap times suffer. How much faster could you have gone late in the race if your bike was smoother? less abrupt? easier to ride. Where in the 9 laps would more power have helped you? where in the 9 laps would less and smoother power have helped you? How can you get the lowest overall time? more power? not very likely will more power make you faster in this scenario, most likely it will make you tired faster, and result in slower lap times and overall times especially late in the race.

Offroad races in particular are won by keeping the highest average speed over the course of the race. Many good riders suffer needlessly at the end of a race, cause their bike is just set up too violently for a full 3 hours, they cannot hold on. Barcia admitted he needed to tame it down, and instantly got better results. Most people would be amazed if they knew the truth, that many big name racers detune their bikes to get better results. Juha Salimen said in an interview he can effectively use about 35 HP for offroad races in the woods. At the ISDE the top guys detune heavily especially on 450's. Very long quiet mufflers are standard fare.

Anyone decent can haul on a fast violent bike for 10 minutes, but that means nothing in offroad racing. How fast are you after an hour? 2 hours? 3 hours? Test this theory scientifically with a stop watch. Be honest with yourself. Spend your money on good suspension set up, make the ergos comfy for you and keep good tires on the bike. Once you study your actual abilities and stop watch verified results, you will likely find more power is the exact opposite of what you need for better race results.

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