Airbox mod/restricted intake

[Thepen]

So I've experimented a bit, and out of pure curiosity I've cut out the inside "tube" that sits in the airbox as well as disconnected the "saddle" part of the airbox. I let her idle a bit, everything seemed fine and i went for a ride. Seemed a bit weird at first but as I've heard the ecu can adapt pretty well I went on, I tested the top speed, and it was still the normal steady 51-52, which I usually get. So I went about my ride into the city for about 25-30 miles. On my way back home I jumped onto a 55mph road and to my surprise now she maintains 55-56 which I could not do before. I pulled a u turn to see if maybe I have a back wind and that's what's helping me putput at a higher velocity, but top speed indeed seems to have increased.

My question to you guys is: has anyone tried a different intake on this bike?

I also wonder how restrictive is the main pipe going from the throttle body into the airbox? It seems thinner
It is a very long and skinny pipe which would generally be a good thing for torque as the air velocity in the stack would help torque.

Maybe a thicker pipe going from the throttle body into the box would help even more?

 

[ball_socket]

Did you ever figure anything out as far as enlarging that fisrt bit of narrow ducting just off the TB?

 

[Thepen]

Did you ever figure anything out as far as enlarging that fisrt bit of narrow ducting just off the TB?

Yes, I ended up experimenting a bit and decided to just throw a pod filter straight onto the throttle body, Do not try that, I wouldn't mod anything with the air intake system unless you have strict control over your AFR's. I went on a ride with that pod filter and ended up swelling/scoring the piston up. Stock Ecu couldn't correct the Afr for the pod filter. In the end I threw a 164cc kit into it with a bigger throttle body and a aracer Ecu and a bunch of other stuff. Now the trail does around 65-70 mph.

 

[ball_socket]

Very cool. I'm curious what TB/how big.

 

[Thepen]

Its a 30mm tb from yuminashi along with the matching Tb ---> cylinder head runner

 

[ball_socket]

Thanks -- I found your other threads talking about it.

I found this that looks like it has a matched manifold and roughly aligns with the OEM air snorkel hose: https://japan.webike.net/products/25105202.html

Might not be too hard to get some 30mm aluminum tubing and some silicon couplers to pipe that TB into the OEM airbox.

 

[Farmer Mike]

Yes, I ended up experimenting a bit and decided to just throw a pod filter straight onto the throttle body, Do not try that, I wouldn't mod anything with the air intake system unless you have strict control over your AFR's. I went on a ride with that pod filter and ended up swelling/scoring the piston up. Stock Ecu couldn't correct the Afr for the pod filter. In the end I threw a 164cc kit into it with a bigger throttle body and a aracer Ecu and a bunch of other stuff. Now the trail does around 65-70 mph.

Now that you've tweaked the drivetrain to run with the big dogs, are you comfortable that the rest of the bike is engineered sufficiently for that speed? Don't read into that, that I'm throwing rocks... I've pushed nearly everything I've ever owned, and I certainly support your right to do so. I've owned and ridden a bunch of bikes in my younger days. My V45 Magna would run way faster than was wise, after 110 that thing became unstable. Just curious if the little Donkey runs OK at that speed, and I get it just because it will do that, it doesn't mean you now use it to commute on the interstate everyday.

 

[m in sc]

my old grom would do 100 (im being dead serious) with a big bore, 4v head, etc, just fine.. will still do well over 85 w the 2 stroke in it.... the trail is more stable overall w the larger wheels, and won't be an issue. few guys have ridden them at speed well over 65 w no issues on stability. (including me). add 250 lbs of shit to the racks, add ons and other things people pile on them...and you might have stability issues. I ran home on mine one day with an HP desktop in the box on the rack, biggest things ive had on it and was doing over 60 for a good ways and was fine.

those magnas were never great handlers though