650R Airbox divider on Honda USA Baja racers

5 replies to this topic
  • BERG650

Posted December 21, 2005 - 09:21 PM


Hi all, :bonk:
Many years ago I read a USA magazine article about the engine setups of the Honda America Baja bikes.

Fairly straight foward stuff- exhaust,headers,HRC cam, open up the airbox cover so it can breathe etc etc.

One mod pictured in the article was an alloy divider plate that fitted between the filter and the carb. NOTE: THIS IS NOT THE FILTER SUPPORT SCREEN.

It was an alloy plate that fitted behind the filter support screen and ran down into the carb air boot .

It fitted edge on and basically divided the airboot(carb to filter) into 2 halves
Apparently, Honda USA were most unimpressed that the magazine had got a shot of it. :cry:

So who knows what it is for? any takers?

Cheers all !! :applause:

  • BajaBoundMoto

Posted December 21, 2005 - 09:47 PM


It's an item that Jonah Street (at that time he was a Team Honda guy) came up with. It's been known as the "Bat Wing" or "Jonah Scoop" and likely other names. It's sold retail by Precision Concepts Racing and probably by 1X International.
Basically the scoop redirects air into the intake so it doesn't create a whirling low-pressure sopt, or a dead spot, in the intake boot.
It works.

  • BERG650

Posted December 21, 2005 - 11:14 PM


Thankyou sir !!. Much appreciated. :applause:

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  • Old_Man_Time

Posted December 21, 2005 - 11:17 PM


I ran the Batwing in my first XR650 but did not notice any real change. It wasn't worse or significantly better. Just put a pumper carb in and you will notice much more improvement.

  • mikekay

Posted December 22, 2005 - 05:49 PM


a far far far far far far far better set up is to put on a pumper carb like every other 4 stroke.

my preference is the Edelbrock.

consider Powernow for more info on tuning the airbox and the intake manifold.

-hope that helps.

  • FZ1426

Posted December 24, 2005 - 02:07 PM


The "batwing" vane is still a good setup with or without carb mods. It smoothes the airflow around the 90 degree bend from the airbox to the boot and increases flow. It works.

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