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Dusty Ratcliff

05' Yz450 exhaust ?'s

17 posts in this topic

Hey I'm new to the 4stroke world, just recently picked up an 05' YZ450 from a friend, the bike had maybe 2 hrs of ride time on a factory rebuild (local dealership) & it seems like a great bike, has lots of power, but still seems to lack a little compared to my 01' CR 250r the bottom end is obviously better, but it just falls off in the higher rpm's was wondering if a better exhaust would help? it's got a 50T rear sprocket & factory front (could be factory rear too but I know it's a 50T??????) & I think he said it had a set of barnett dirt digger clutches?? what would be the best $ spent on this thing to pep it up a bit??? thanks alot! Dusty

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Slip-ons for the '03-'05 YZ450 are mostly bling. The stock pipe is very good, and it not that easily improved on.

The CDI unit controls the "map" for how and when the ignition timing is advanced or retarded. The map on the '04 was much more aggressive than the '05. Not sure if the connectors match up between the two years, but the timing map is the only real difference in the '03/'04 and the '05 as far as power goes.

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The only real power gains from an exhaust would be if you got the complete system and then re-jetted it slightly. This will be a noticable change. I would recommend the Pro Circuit Ti-4. It's a little expensive but it does its job. Also the vortex ignition is amazing. It has I think 10 different power curves and you really can tell a difference between them, and theres one that will suit pretty much every riding style and different riding terrains.

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The only real power gains from an exhaust would be if you got the complete system and then re-jetted it slightly. This will be a noticable change.
The best pipes I've seen on dyno charts on '03-'05 YZ450's have done no more than move the power around, adding two at the most at one point on the curve, and generally taking away from another part of the curve to do that. The overall softness of the '05 compared with the '04, or even one of the later ones, is not curable with a pipe of any kind.

OTOH, some people like them as they are, and there's nothing wrong with that.

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When the bike is tuned correctly with a complete system it will make a difference. It's not huge, but it is noticable. I have an 05 yz450 and it pulls stronger up top with the pipe...the ignition did make more of a difference though

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That's my point. The cams, carb, rotating mass, and exhaust of all the '03-'05 YZ450's were exactly the same, other than the '05 was the first YZ450 with a leak jet, and the '05 head was actually better than the earlier ones. Yet, the first complaint almost everyone had about the bike was that it had no low end power, and accelerated poorly. The only difference is the ignition mapping.

It was changed to address the popular complaint that the '03/4 was unmanageably snappy. They overdid it.

As I said, the best pipes, optimized for the bike, will add no more than two anywhere in the range in these year models. And yes, that would be noticeable, but not, as you say, as much so as correcting the timing map.

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can I get an aftermarket ignition from Vortex that's not adjustable?? I don't think I could get any riding done with the one that has 10 different setings, I'd just be fiddling with the dang settings all the time!!! lol also I only saw the adjustable ones for the 06'-up bikes???? do they make it for my 05'??? thanks, Dusty

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Ya they make it for the 05, i have one on mine. It actually has a switch on the bars that just switches between two of the settings so theres not a whole lot to mess with when you are actually riding. To switch between the other ones you have to select them down on the box when your off the bike

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It is a huge improvement over stock, and I can definiately notice a difference between each of the settings. The biggest changes from setting to setting is where the majority of the power is. I tested them out, I rode a lap with one setting and then switched it and rode the next on another setting, and i could definiatly feel the power in different places. They have a setting for pretty much everything, some are all about low end torque while others are almost all top end, some are just kinda an all around improvement from stock, and one is even for more of a mild hit kinda taming it down. I am running the Pro circuit Ti-4 low boy system and went up a few on both the pilot and main jet.

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Great info here thanks guys, so what did you finally do? Did you get a pipe and or the Vortex ignition. I have a 05 YZ450 as well and have been wondering if I should replace the pipe or not but it sounds like there is other ways to archive the power goals with out changing the exhaust , which is pretty pricey for me. I've tried looking for the Vortex ignition but can't find it any where so if someone knows where to buy them please let me know..:thumbsup:

Thanks again for the information here..

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The only real power gains from an exhaust would be if you got the complete system and then re-jetted it slightly. This will be a noticable change. I would recommend the Pro Circuit Ti-4. It's a little expensive but it does its job. Also the vortex ignition is amazing. It has I think 10 different power curves and you really can tell a difference between them, and theres one that will suit pretty much every riding style and different riding terrains.

AMEN! The Pro Circuit GP system is awesome! but i blew mine up :p Running stock again and I miss all the bottom end power. I used to be able to pull the front wheel off the ground after topping out in 4th gear by just letting off the gas and getting on it again but now I have to jerk it pretty hard to get it up! :lol: last 11 words :cry:

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AMEN! The Pro Circuit GP system is awesome! but i blew mine up :p Running stock again and I miss all the bottom end power. I used to be able to pull the front wheel off the ground after topping out in 4th gear by just letting off the gas and getting on it again but now I have to jerk it pretty hard to get it up! :lol: last 11 words :cry:

lol, Nice

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Great info here thanks guys, so what did you finally do? Did you get a pipe and or the Vortex ignition. I have a 05 YZ450 as well and have been wondering if I should replace the pipe or not but it sounds like there is other ways to archive the power goals with out changing the exhaust , which is pretty pricey for me. I've tried looking for the Vortex ignition but can't find it any where so if someone knows where to buy them please let me know..:p

Thanks again for the information here..

Hello ??

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