The problem with the stock airbox is that it does not flow as much air as the carbs are able to, and therefor limits the power thw engine could be producing.

The answer is to remove this restriction of course, and the ultimate is no airbox, or the HRC setup. Fine for the track, but a bit extreme for the road.

Next best is no airbox lid, but I for one find this extremely loud.

The last option is to open the lid up to allow as much air in as the carbs can flow, but how you do it is up to you. Trial and error seems to have discovered that four 1 inch wide holes give sufficient air. I decided to simply cut off the restictive trumpets, and keep the intake in the same genral area as Honda made it, but the overall effect is the same.

I have also removed the web from the airbox lid, though I've no idea if this has any effect or not. I always intended to remove the one from beneath the filter, but somehow never got round to it...
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