I am trying to find a cheap air filter off ebay for a mikuni swap on my GTR. I can't seem to find anything on here giving a part number or specs (size etc). I see that many people have purchased some off ebay or amazon for less than $10 but need to know what size. Everything i have found is too long.

anyone? I cant seem to find one that will work. Does anyone have the dimensions for the k&n or tau?

Measure the intake side of the carb. Then measure the space between the carb and the exhaust. Find a filter that had the appropriate diameter for the filter boot (I think it's approximately 62mm, but could be wrong there), and isn't to long to fit in the spot between the carb and the exhaust. The tau ceti from MudBuddy is actually a spark arrestor, not a filter.

Edit. I checked the math. It's 2.5", or 63.5 mm. You can tighten a clamp enough for a filter boot that's a couple mm to large and make one a tad small stretch, so 63mm - 66mm ought to work.

Anything less than 4.5 inches long ought to fit

I only have 3" from the carb to the heat shield on the stock exhaust. Is that normal?

just went and measured. It's around 3.5" without the heat shield.

FA-TOR-25-BLK
That's the part number for the tau ceti flame arrestor.

Thanks guys.