Hello - I am new to the forum after recently buying my first Honda Four, a clean, mostly original 76 CB550. I cleaned and rebuilt the carburetors to stock specs and seem to be running on the lean side. I also replaced the foam filter from the PO with a stock paper unit, and noticed that both the air filter retaining spring and the bottom foam element and "element cover" were missing inside the airbox. With nothing to stand on or hold it in place, the stock filter has a decent amount of play and probably isn't forming a very good seal at the opening.
In the '76 addendum sheet for the CB550, it shows the breather tube being routed away from the airbox. Did these models still come stock with the bottom foam element and metal element cover that goes through the hole in the bottom of the air filter element and holds it up?
I'm wondering if these small variances could cause enough change in the position of and flow of air through the filter to affect the mixture. These parts seem hard to come by so I'm thinking of rigging up something inside the airbox that holds the filter in place and plugs the hole at the bottom. I'm also going to replace the rubber boots from the airbox to the carbs, and they're dry and cracking.
It's also worth noting that this bike was fitted with a 4 > 2 exhaust stamped "HM ME5", which as far as I can gather is from a mid 80's CB650. I'm not sure how this might affect carb tuning.
Excited to be here and learn more about this great bike.
