2005 WR450 Airbox Noise

4 replies to this topic
  • draver

Posted March 12, 2005 - 09:07 AM


Did all the basic mods to my new WR450, JD Jetting Kit, Snorkel, Grey Wire, Exhaust Plug, Throttle Stop. During a test run on the beach at Sand Lake, OR at about 40-50 mph in 5th, the air intake moans very loudly, kinda like an 850 CFM Carter AFB. Is this normal, and if so, does it mean I need to cut out the right side of the airbox to get more breathing? I mean, it's LOUD, thought I was being paced by a helicopter or State Trooper Cessna!

The power difference is incredible, I'm surprised they actually sell the bike this crippled when all that engineering is going to waste with the stock setup.


  • jasilva

Posted March 12, 2005 - 09:34 AM


Seems to me that you were loading the engine down pretty hard at low rpm by running 5th gear in sand that slow. I have the same mods on my bike and never hear a moaning from the airbox. But I try not to stay in the bottom of the rpm range. Its been a while since I had a carburated car but the only time I ever heard that was when I was bogging the engine down and then opening the throttle wide open. Try that test again in 4th at that speed and then try 5th a lot faster.


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  • draver

Posted March 12, 2005 - 09:47 AM


I imagine that's possible, but it was on the hardpack just above the water, plus I was running a 10 paddle. I don't think it was lugging or bogging, since it still had a very snappy throttle response and was just loafing along. I could actually look over my shoulder and see my roost about 15 feet in the air, and if I goosed it then, it shot up even higher. I was impressed with the response while just cruisin' along.

Do you think the stock gearing is set up to only get into 5th gear above 40mph? Seems like that would be pretty long legs. I did notice that in the soft sand, I seldom got above 3rd gear to keep pulling.

  • jasilva

Posted March 12, 2005 - 04:50 PM


The stock gearing on the 450 is good for about 95mph. So at 50 or so you were probably lugging a bit.


  • draver

Posted March 12, 2005 - 05:28 PM


I suppose that's possible, I see from the manual that 5th is actually an overdrive at .84/1 but if 95 mph is top speed in 5th, and max RPM's is around 12,500, wouldn't 50 mph be turning over 6,000 RPM? I'm just thinking that this engine pulls very hard from the bottom up, and it's hard to imagine lugging it at 6 grand.

Anyway, this thing pulls like a late freight from just off of idle since I made the mods, I was just wondering if anyone else had heard the same intake noise. Kinda reminds me of my old '65 GTO without the air cleaner !

I guess I need to do some more testing. I wonder if it could be a crosswind. I only noticed the "Honk" while going one direction, and I know some bikes are intake sensitive to very specific crosswind conditions.

Thanks for your comments.



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