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redsoxfever

q4 powerbomb on 04 yz450f

12 posts in this topic

I've read a few articles on exhaust here.......i realize Q4 will be quieter with powerbomb then stock exhaust but will there be much difference in torque et? Is it that much quieter? I have an 04 yz450f and would like to keep bike quiet if i can without compromising too much power. Would the bike run lean? Would i have to adjust jetting? Sorry if i missed this in another forum..........i've searched and didn't get exactly what i was looking for. Engine is rebuilt, cases, crank, piston, sleeve etc.......and am looking to gain the most from that expense

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No one has the Q4 and powerbomb on their yz450??? Any year yz450f riders feel free to comment on how they feel this setup has worked for them.......just looking for general yz450 input on "quiet" pipes or if another combo has worked better that info would also be appreciated

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No expeience on a 450 but I like the Powerbomb Q4 combo on my WR250F so much I just bought a Megabomb and Speed w/quiet core insert to put on my YZ450F.

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I had a Q4 on my 04YZ for off road. I had the stock header. It quieted it down a lot but was still louder than say a stock WR. As far as power it smoothed the low to mid range hit a bit but still reved and made good power on top.

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The Power Bomb will not reduce the sound level by more than about 1 db. Neither will it add any peak horsepower to the engine. What it will do is tend to widen out the power curve of the engine somewhat, especially on the lower half of it. They're nice if you can get one used, but they are kind of pricey otherwise, and not a really great value for what you get, IMO. You might just start with the Q4 and leave it at that for a while.

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Had a Q2 on my wifes 250F. It was a slug off the bottom end but it would rev nice. Its been replaced with a Yoshimura full system, which is loud, but it rips. :)

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hey gray........haven't ridden a ton of bikes and this is my first 450 or should i say 4 stroke......when you say widen....you're telling me it will produce or have more power (not hp) but torque through the gear range? Would the q4 be more restrictive then stock exhaust sine from what i've heard is quieter? Would a powercore with powerbomb be better and then just throw quiet insert and spark arrestor in if and when needed? Is the powercore that restrictive with inserts that performance would be any worse the Q4. What other slip ons or systems are people getting great power from and then slipping arrestor and quiet inserts to ride noise restricted areas?

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  1. .....when you say widen....you're telling me it will produce or have more power (not hp) but torque through the gear range?
  2. Would the q4 be more restrictive then stock exhaust sine from what i've heard is quieter?
  3. Would a powercore with powerbomb be better and then just throw quiet insert and spark arrestor in if and when needed?
  4. Is the powercore that restrictive with inserts that performance would be any worse the Q4.
  5. What other slip ons or systems are people getting great power from and then slipping arrestor and quiet inserts to ride noise restricted areas?

  1. More power and torque at the lower and upper ends of the curve, yes.
  2. The Q4 is both quieter and more restrictive than the stock YZ system.
  3. About the same as the stock system, but with a flatter curve when open, somewhat inferior to the Q4 with the insert. No difference with the sparky.
  4. Yes.
  5. Like "he" said, look into Leo Vince systems.

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Really appreciate the info.............i will check into the Leo's. Have never had an aftermarket exhaust and a 100 plus for the billet end cap seemed a bit much....would rather put that money into an exhaust. Previous owner gave me a big gun slip on but said a lot more noise and didn't notice much in ther terms of power gain so have never put it on the bike. Will just a Leo slip on improve over stock exhaust or will i only see gains in a complete system

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In terms of raw power, YZ450's up to the '08 model have all had excellent stock exhausts, and as such, it's difficult to improve on them. In the particular case of an '04, no aftermarket exhaust will gain more than 1.5 hp at peak according to any dyno test I've ever seen. Some do improve the performance a little from the standpoint of smoothing out peaks and broadening the power curve, but that's pretty much it.

Read:

http://www.thumpertalk.com/forum/showthread.php?p=7489676#post7489676

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