Should I replace my air filters?

[e3steve]

Ed, as always, thanks for sharing the interesting history there. So the fact that my (and, as you mention, some others' you've seen) head vents are looped would meet with your approval? Technically-speaking, I mean; as opposed to not 'originally-correct'.

I ask these questions because we all learn massively from you here; and what's correct and what's tecnically-acceptable can be right for one and 'right' for another, but for different reasons.

Regards,

Steve

[Spargett]

Very interesting, and ripe with logic ; )

Scott you are new to this. The early/original filters were designed/made for the CB72 (250) which was produced B4 the CB77 (305 and that bike used/had "power jet" carbs which had a special enriching system which required fresh clean air so HONDA installed small tubes from each carb to the corresponding air cleaners. That design also had the intake valve moisture removal passages which attached to a plastic "Y" and the one end of the "Y" had a tube which attached to a second (larger) tube on the right side air cleaner.So the right side air cleaner was issued with 2 tubes of different sizes. Along came the CB77 and the carbs didn't have the "power jet" system so HONDA installed RED soft rubber covers on the smaller tubes. The valve vent tube was attached to the larger tube same as the CB72. Some time in 1967 HONDA discontinued the valve vent system and at that time it seams all the air filters "CL72/77 included" were manufactured without any tubes on either filter and the head no longer had the "drilled/taped and threaded" locations. Some heads were issued with the casting area for the holes to be drilled and later the heads were issued with no evidence of the "vent system" at all existed. When I do a correct restoration I make a "large" tube with 1/4 in. brass tube soldered to a steel washer then installed on the right side filter with JB Weld and sprayed with KRYLON dull aluminum paint. If a person wants a rider and doesn't care about the bike having the vent tube being there (HONDA dropped it anyway) he/she can put 10 mm bolts in the holes in the head or install a rubber tube from one vent to the other. I see many restorations which have the tube/Y installed and the air cleaner end just hanging in the open and not attached to anything. Oh Well. ................lm