Airbox Modification

[BykBoy]

Well, winter is here and there is nothing to do but tinker with the bike. I went up to my friendÌs shop and we did some mods to the Airbox.



Intro:



The Airbox is divided into three sections. Front section has one intake hole on the left side with a short snorkel in it. The right side does not have an intake hole and it holds the air temp sensor. At the back of the front section, there is a divider with two holes, roughly two inches in diameter. This divider forms the front wall of the middle section. The back of the middle section is the rectangular air filter. The air filter separates the middle section from the rear section. The rear section has three holes in it at the bottom which connect the airbox to the throttle bodies.



I didn't have my camera with so will do my best with some sketches.

[BykBoy]

The Mod:





We cut a large hole on the left side of the box and a similar size hole on the opposite side.



We then cut a large hole in the divider that separates the front and middle section.

[BykBoy]

The result:



Engine response: The cat sure feels more responsive after the mod. The engine definitely revs quicker and with no hesitation at the low range.



Noise: The high pitch wheezing sound I had before the mode is gone. The engine makes a louder noise at higher revs. Tone is lower pitch and deeper. It feels like it has more volume (maybe like a bigger drum?). Kinda like it sounds when I rev the engine in a tunnel or a parking garage. I can actually feel the sound in my chest when I hit the high revs.



Power: It sure feels like it's got more grunt. But to be fair,  that could be the cold air, my more aggressive throttle work, or just my wishful imagination at work.



Down side: IÌm not sure how the box will react to water crossing or heavy rain. It looks like the large openings on both sides may allow more water in then the original short small snorkel. Will this have a negative impact on the engine in the long run? Who knows... It surly feels more spirited.

[Patrick the Scot]

O the grips of winter has placed another motorcycle on the operating table to under go the carving up with a dremel tool! It sure is predictable: when the cold weather sets in the O.R. gets busy.  



Do you think you will have to install a new tune? Or is the present tune sufficient?

[BykBoy]

Do you think you will have to install a new tune? Or is the present tune sufficient?

So far so good. I have the Triumph sport muffler on and the tune that goes with it... I rode to work this morning and everything seems to work great. However, it's 20 degrees outside and that may have something to do with it. :roll:

[tomla]

I'm going a bit slower, starting with smaller holes.  I don't REALLY notice any performance increase....I'm doing it for the mileage increase, if any.  After I got the race tune, my mileage dropped.  

The mod listed must be pretty loud, because my lesser mod is quite noticeable.  If you're concerned about noise, drill a few smaller holes (3ea 7/8") on the right front and leave the snorkel in...though the snorkel can be improved with an exacto knife and a dremel.  I used 5ea.  7/8" holes in the divider plate.

I will say that the noise is pretty cool, though...kinda big V-8 like.