trail rider Posted April 24, 2004 Report Share Posted April 24, 2004 does a aftermarket pipe really do much for a 4 stroke? About a month ago I bought a white bros R-4 exhaust for my ttr-125 and I can barely notice any power difference, except that it takes longer for the revs to drop and it sounds better. Was this a waste of $220 or do I need to do something else to it? Should I change the jetting? Quote Link to comment Share on other sites More sharing options...
Wassup350 Posted April 24, 2004 Report Share Posted April 24, 2004 To get any power increase you would have to rejet it. The power increase isn't anything like you can get out of a 2 stroke though. I think that you would get more power out of a performance header also rather then just a new muffler. Quote Link to comment Share on other sites More sharing options...
ranshee Posted April 24, 2004 Report Share Posted April 24, 2004 You also have to remember its only a 125 four stroke. Your not gonna get that way faster feeling even if you added another 50 cc to it. So you basically made a 220 investment in the sound quality, which is not a bad investment. At least it sounds good right. Also you are gonna have to rejet to feel the increase in power. Quote Link to comment Share on other sites More sharing options...
hamuel Posted April 25, 2004 Report Share Posted April 25, 2004 A friend just put a LRD Pro 4 Exhaust on his honda 400ex. before it couldn't keep up in 5th gear. now he's hanging around the i goose it in 6th. so they do add quiet a bite. Quote Link to comment Share on other sites More sharing options...
Wallrat Posted April 25, 2004 Report Share Posted April 25, 2004 (edited) It definately makes a difference but any changes made to the intake/exhaust will require a rejet. Also its usually a good idea to take a look at the intake at the same time you're changing the exhaust, stock systems are usually fairly restrictive on both sides of the equation. When I slapped a Big Gun Race pipe on my wife's 300ex I had to go up 5 jet sizes, when I removed the airbox lid, I had to go up another 4. That thing couldn't get into 3rd on a decent incline with me on it, now I can pull 4th no problem. -Just reread your post. If you changed the pipe and not the jetting, DON'T RIDE THE DAMN THING! Serious engine damage can occur since you now have more air with the same amount of fuel. You're running lean my friend. Pull out your plug and take a look. It should be cinnamon brown. If its white, your well on your way to destroying that bike. Increase the jetting as per the pipe manufacturers recomendation for a start. Edited April 25, 2004 by Wallrat Quote Link to comment Share on other sites More sharing options...
BansheeBrian Posted April 25, 2004 Report Share Posted April 25, 2004 It's worth the investment.Make sure you get both pipe and silencer.Now that you have messed with the exhaust, increase air movement and rejet.Keep up on the packing as well and you're good to go.White bros E series do exceptionally well on 400ex's from what i know. Quote Link to comment Share on other sites More sharing options...
trail rider Posted April 25, 2004 Author Report Share Posted April 25, 2004 The whole thing included a headpipe and sliencer. But how do I know what to change the jetting to? They didn't send any kind of jet kit or anything. Quote Link to comment Share on other sites More sharing options...
Wallrat Posted April 25, 2004 Report Share Posted April 25, 2004 Read the instructions, try their website. If all else fails, see if you can find a board or ask the stealership. Quote Link to comment Share on other sites More sharing options...
Nightrider Posted April 25, 2004 Report Share Posted April 25, 2004 Some stock exhaust systems are actually very good from the factory,Like the 400ex/Z400.Aftermarket pipes for these machines only add 2-3 horsepower.Where as a machine like the Raptor gains a minimum of about 10-11 h.p average. It all depends how detuned the engine is and how exactly they detuned it.If the manufacturers used the exhaust system to lower the power output to meet certain levels of reliability or safety,then large gains will be seen with aftermarket exhaust. Quote Link to comment Share on other sites More sharing options...
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