best exhaust and mods yfz 450

hello, I have a 2006 yfz 450. I don't think anything has been done to the motor, I may think it had a top end rebuilt as there are wiseco stickers on it but I don't know If they were put on there looks. I was wondering what is the best sounding and performing exhaust for my yfz, I want something really loud but yet still a noticeable gain in power and im looking for full exhaust not just a slip on. I was looking between fmf megabomb header with fmf titanium 4.1 or a full Curtis sparks big core exhaust. I understand the sparks is louder but which one has a better sound? also I am wondering which mods are best for speed yet the motor is still reliable. I drive around several hours a day so it needs to be safe. I was first doing the oil update since they had problems with that but I was thinking some hot cams, I was thinking stage 1 since I don't think they have stage 2 for these but also a new airbox setup and eventually ported and polished heads but what do you guys recommend for exhaust and mods? I was also wondering about that zip tie mod if I don't have to worry about it or its completely safe cause I really notice where it bogs at first crack in throttle and my last question is if I get a new exhaust if the header will still glow red or its just from the factory metal?

thanks for the info, help and replies!

I wouldn't worry about exhaust for now. Use the money for a fresh rebuild/top end and valve adjustment since you are unsure of hours and condition... I would rather have piece of mind with a solid engine vs exhaust...and put a hour meter on it...

how much does the top end rebuild cost? and how hard is it to adjust the valves? Im going to get a trail tech soon so that thing will have everything but the yfz looks in great condition but I don't know hard it was rode but one of the previous owners tried doing a wheelie and it got away from them cause the rear grab bar is scraped but I don't know. I think im going to do that oil update first if it hasn't been undone because I don't like riding and thinking the crank wont get oil and that goes out but when ill have the apart ill look at the top end and check it out. but what would recommend Curtis sparks or fmf muffler with megabomb? and what mods?

Cams are the biggest bang for your buck but if you put the wrong cams in it will hurt performance. Perform the necessary intake mods, have the motor ported and then decide what to run for cams. I went with web-cams on my kfx after all the motor work was done, it turned out great and was an absolute beast while running. That's where you're going to run into some problems though, a heavily modded bike isn't really very user friendly. They're much higher maintenance, need to be rebuild all the time and can only run right on race gas. If you're looking for a fire breathing monster capable of out hauling every other bike on the trails, a 450 isn't the answer. From the factory they are very high strung and there's not much you can do to them to make them run better without making major sacrifices other places. A more free airbox is a start, a good high end exhaust system (a slip on does little to nothing), jetting and a rebuild is about the best you can do unless you want to spend more time rebuilding then riding. The other option is to sell your bike and get something faster like a banshee, those can make 70 hp easy and still be reliable. 70 hp from a 450 is do-able but near impossible, will cost thousands and thousands of dollars and the bike will be in the shop most of the time anyways. I would have saved myself a lot of time and money if I just sold my KFX and got a Banshee or even a 700 raptor. 

Raptor all the way. In my experience, banshees go through pistons like a kid goes through Halloween candy. I have modded my Raptor for durability and reliability on pump gas. Stock they put out 38HP'ish. I have mine pumping out 60HP on stock bore and stroke, drinking 91 pump gas. Excellent trail machine and loves a long straightaway to let its legs run, lol.

Edited by morphrider

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