Narrow Ham Can Airbox / filter - Pros and Cons

Rorty71750 · Feb 3, 2026

I've owned my 71 since 1987. After many years of dreading the stock air filter change, I've gone with a 1 inch narrower filter and have narrowed the outer gauze to fit. I have yet to ride with this new configuration.
With a smaller air box, I would think that would result in a richer fuel / air mixture. I'm thinking I may change the needle jets from 106 to 105. What are people's thoughts? Has anyone here have experience with this modification?
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concours · Feb 3, 2026

Rorty71750 said:
I've owned my 71 since 1987. After many years of dreading the stock air filter change, I've gone with a 1 inch narrower filter and have narrowed the outer gauze to fit. I have yet to ride with this new configuration.
With a smaller air box, I would think that would result in a richer fuel / air mixture. I'm thinking I may change the needle jets from 106 to 105. What are people's thoughts? Has anyone here have experience with this modification?
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robertv · Feb 3, 2026

No expert here, but my 850 has never run so good since I put the stock cleaner on. Plugs are very clean, I may need to jet up a bit. Mine has a K&N style element inside. Easy to remove and install. It is a well designed unit. But I would expect that from Norton. My Amal Premiers have the circlip at the lowest position.

Narrow Ham Can Airbox / filter - Pros and Cons

Rorty71750

concours

robertv

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