Airbox modifications cannot be made while still using the OEM exhaust system! It is far too restrictive, and cannot scavenge out the burnt exhaust gases quickly enough. At best, the engine would run badly and choke out in short order; at worst, there would be sufficient carbon buildup in the cylinder heads to very soon require a teardown, due to too much backpressure.

At the very least, the rear baffles of the OEM exhaust system must be removed; an excellent step-by-step procedure to do this on an 800A or 800 Classic can be found at Pusher's page (sorry, Drifter owners, I don't have any info on how to do this to yours. I have a request in to some Drifter experts on it; as soon as I have a proven procedure, I'll post it). One thing to take into account is that this will rob the engine of a horse or two vs using aftermarket performance pipes.

If the intent is to retain the unmodified OEM exhaust system while modifying the air intake system for greater power, you might as well go back to the Myths, Legends and FAQs page.

WARNING! Individuals perform this modification, as well as any other modifications suggested in these documents, at their own risk. The writer and editors/collaborators accept no responsibility or liability for any loss or damage to the modifier’s person or personal property arising from use of this document.

If the OEM exhaust system has already been debaffled, or replaced by an aftermarket set, then have a look at what's available.