WB Aluminum Pro -05 CRF450R- is it true?

Installed the Aluminum Pro and Twin Air filter that was included w/exhaust system. Kept the stock filter cage. Went to the track began with 1 7/8 turns out (stock) on the fuel screw and all stock jetting (168 Main). Long story short the bike felt sleepy and had some hesitation (boggish) off of idle and more so in the mid range. Kept backing out the fuel screw 1/4 turn at a time and would click off some laps come back 1/4 turn out do more laps etc... Bike continued to feel the same until I finally stopped at 2 1/2 turns out. Came back pulled the plug and it looked completely normal. I don't have any other jets so now wanting to get as much info before I start changing jets and clip positions etc...

Called WB talked with someone in their tech department and and asked for a recommendation. WB told me to change the main jet to 175 and go up 2-3 on the leak jet and bring the fuel screw back to stock 1 7/8 turns out and keep the needle in the stock position.

According to the hype this exhaust is supposed to make the 450R hit a lot harder (more crisp) down low and harder (more crisp) though the mid range relative to the stock setup. At Stock my bike hits very hard down low all the way through the mid range and my expectation/hopes are that I can at least get the same hard hitting feeling from the WB exhaust and maybe a more crisp throttle response in the low and mid range.

I'm at 500 ft elevation + or - 100 ft. My average temp is around 60-65F (Winter) and will jump to around 85-90F (Summer) with high humidity. Any info on this subject would be greatly appreciated. I don't have a lot of time to wrench b/c of my job and want to get this thing tuned as quickly as possible. If I can save a lot of time and find out that this exhaust isn't really what it's supposed to be then I'm fine with simply returning to the stock setup but I'm hoping that isn't the case. Thanks in advance! :?:

making the main jet a rich as they suggest will just make the motor more sluggish.

sounds to me like the pipe is just softer down low.hype is just that hype.

So where is the jetting help in this response? Curious because I'm about to purchase the same bike (but 04) and exhaust. My personal thought is that I'm going to go richer on the main and play with the needle to see if it needs to be leaned out to compensate for the richer mainjet - which WOULD give it back some of the crisp feel if I'm not mistaken. Any comment?

no,i reality that pipe probably needs less main jet becuase of the increased scavenging effect.

regardless,tuning a "soft" bottom end has nothing to do with the main jet.

my personal though as stated is that the particular pipe is just softer than the stock pipe down low.

I had this pipe on my O5 CRF and here is what worked the best. Stock Main, Stock leak, and run the fuel screw at 2.5 turns, or go to a 45 pilot and run 2 turns (did that on my brothers CRF, same result). I ran twin air filters, but took the screen out. they are heavy and restrictive. I did the screen before the pipe, and noticed a difference just from that. the WB aluminum pro really made the bike worth having. my elevation is about the same as you. different climate, but same elevation.

Burned thanks because I'm looking forward to playing with this when I get it - eventually going to one of the Athena big bore kits to see how it runs. I appreciate your comments. Mike

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