Stock XR650R and full exhaust system?

25 replies to this topic
  • XR4DEZ

Posted December 20, 2006 - 07:52 PM


Add the number 1x on the number plates, if you really want some power.

  • philipstjohn

Posted December 20, 2006 - 08:51 PM


Add the number 1x on the number plates, if you really want some power.

When my number comes up, I will let you know so you can have the edge!:devil: :thumbsup:

  • philipstjohn

Posted December 20, 2006 - 09:08 PM


I am all about racing...I bought this bike to run the 1000. I just started with the suspension, and working on standard mods. Where should I go from here?

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  • motivater

Posted December 21, 2006 - 12:20 PM


it will run bad unless you open the air box/change carb boot/and jet it

I put a white brothers slip on exhaust on mine....jetted it.....but did no ther modifications to carb or anything else and it runs great!!!!!

  • motivater

Posted December 21, 2006 - 12:22 PM


So, a XR 650R uncorked, stock motor, stock header- which is best- the White Brothers E series pro meg, T4 Pro Circuit, or the FMF Powercore? Any comments? Suggestions? Thanks guys... :thumbsup:

White brothers slip other modifications........has more power and runs great!!!!!!!

  • BWB63

Posted January 02, 2007 - 09:41 PM


The adjustablility of a disk type muffler like the Whitebrothers 'E' series is great because of the tunability of both the sound, power and still have a sparkarestor when needed. The Pro-Mega 'E' series was the best. Running it wide open (no back plate) gave great power (loud), with the back plate & 12 disks was good power and not to loud, 8 disks is sound legal 96db, some have gotten away with twelve at the sound check but, I think it is 98db. If sound isn't the issue the saving weight would be my goal and the T4 or E4 are the lightest. Staintune is awesome but, I would buy the whole system to make it worth while. The head is real nice. It has most to do with what you need most, if you are looking to open the bike up a little more and keep the sound down, get an ajustable muffler (not just an insert), if you need more power the get a full system. If you are looking to make the bike lighter, then get a light system, Like the full T4 Pro Circut, FMF, XR's only with an R4 and make the bike faster in the higher RPM's at the same time. If you don't want to spend money and weight isn't an issue, keep the stock exhaust, take the inner can baffles out (if you take your time you can bend them back and forth till you snap the spot welds) Here aree some pictures of the inside of the mufflers where the baffles are:
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Then run a stock tip drilled out to 2" and it will give you more power. No tip if you want loud.

The header is where the exhaust is bottled up the most when it comes to adding more power or pushing the power up in the RPM's. If you look the stock headers choke down about 2" out of the head. The other headers remove this restriction. In the order of exhaust flow after stock of headers I would put them in this order. XR's Only, Whitebrothers, T4, Power bomb, Staintune, Big Gun, Akrapovic, I rode a Motard bike the guy said, it had a Yoshimura header on it and it was a built HRC bike but, I have never found a place that sells the header, Barnum's Pro, Moriwaki, I have owned or riden XR650R's with these headers on them to the point of felling the difference in the power delivery. What makes it less factual is each bike was built different. Some are so close in flow it is a guess in what flows better. So, depending on how much power you want to keep down lower (stay with the XR's Only side) or more power up top (Staintune) or a biult bike Barnum's, Big gun, Moriwaki

I am all about racing...I bought this bike to run the 1000. I just started with the suspension, and working on standard mods. Where should I go from here?

If your all about racing then the bike has to breath to get the extra hp in the higher rpm's. If we are talking pushing it through the whoops at 70mph+ and you start swapping the back end that is when you need the extra 5+hp to straight out the bike. Look at the dyno charts and you will see how getting the bike to breath flattens out the power curve in the upper rpm range.
4th chart down shows how the stock bike falls off and the bikes that breath carry a more flat power curve. Stock header noses off in the higher rpm.
A quiet race bike?
It is where the horsepower is needed. Yes, an open exhaust system makes a bike rip compared to a stock uncorked bike but, only in the high mid to upper rpm range and for most that is not needed but, some said, race, then quiet, then why waist money one a few horsepower (5rwhp at 6800rpm is 10% power gain). Like I said, most only look at peak horsepower and that is only 2rwhp with a free flowing exhaust. That is around 5200 rpm. If you race you stop thinking just about peak horsepower and about where you need it and when. Mike Powells Baja 680cc bike rips but, when the team was racing the Baja David Gray said, there was to much horsepower down low for his huge 148 pound body going through the rocky steap section but, he said it also was awesome to have all that power to pull the bike straight at 100mph. Once you get a free flowing header and pull the whoops at high speeds you will feel the difference. The bike will feel not as strong when you first blip the throttle compared to the stock header but, you learn to get the bike up in the rpm's quicker. I am not selling what I have or run as "perfect for everyone" one think sense they have it, then it must be the best. Most haven't had six different exhaust systems on their bike or tried 20~30 different setups but, if they bought it, then it must be the ticket for everyone! In reading what I wrote earlier I try to get the point across that the main difference is the personality of how the power comes on and when as the difference in the more free flowing exhaust systems. Staintune, FMF, White Brothers, Xr's Only, Pro Curcit as great systems (ohhh, did I leave out Big Gun?) Big gun works also but it seems to be better with a cam or HRC kit, (I have noit tried the new system the old system has a bigger header pipe then the others) then the open bikes with cam, piston or big bore would be Moriwaki, Barnum's Pro, Akrapovic The diameter of the header and how they collect and the size of the mid section change the way the header will flow the exhaust. Some of the headers (XR's only that I ran) don't collect the two into one as well as say the Staintune so, the XR's only header keeps a little more of the bottom end. Trade off's so, getting what you want is what counts not what others bought.

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