Topic: 1978 CB550 score

[Scott S]

 In fact, the same guy that's parting out the '75 that I got the seat from has some headlight ears and turn signals for the '75 as well. Any reason I couldn't make those work on the '77? How different are the headlight ears?

[ACVWguy]

You mentioned you had a flat spot at about 5000 rpm... That is most likely related to the throttle position in the carbs more than actual revs (as it usually requires about 3/8 throttle to maintain 5000 rpm in 5th gear). 5000rpm seems to be the spot that flat spots like to occur - but I've found that those flat spots are usually caused by some sort of deviation from stock intake draw (like free flowing filters (lean) or clogged filters (rich)).

In the short term, I think you'll find that the flat spot you're experiencing will disappear if you seal up that intake boot, as it is creating a leak that will cause at least one cylinder to run lean (and possibly overheat). And if that doesn't work, replace your air filter. An old filter that is clogged and worn will cause your bike to run rich, dirtying plugs, wasting gas, and sacrificing power. I can't tell you how huge the difference in performance is when you replace a 30 yr old air filter with new. Expect a huge boost in power, cleaner plugs, and better mpgs. Just my experience.

Sweet bike tho. I dig the maroon.

[Scott S]

 Along with the air box and boots from the '75, I also got a Uni filter for the stock air box. It's in there right now.
 I'm waiting to hear back from a forum member about some boots, but if I take it out for a ride before then I'll at least wrap some tape around that torn boot on #1.

[cb550inct]

Scott this is freaky...i just ordered the uni filter for my 78 as well. Dont tell me you just bought new tires too.

[Scott S]

 Hehe, no...but the 550 has a new tire on the rear. And a bald one on the front. I swapped some Uni pods and a little cash for the seat, air box/boots, and drop in Uni filter. Found a local guy who's making some changes to his '75 550. Worked out great for both of us.

[Scott S]

 You know, even though the bike smoked at the shop when I got it and on the ride home, I can't seem to make it smoke now. The shop owner said that he thought it may have had a stuck valve that's now loose or something.

 I can get the idle down to 1100-1200 rpm, but it starts making a noise that, to me, sounds like the carbs are out of synch. It also has a hanging idle after giving it throttle when I keep the idle down.
 I checked for an intake leak, and if it has one it's small and intermittent.  I think  the carbs are just out of adjustment.
 I think I'll pull the carbs when I get the new air box boots, give them a good cleaning, set the floats and synch them.

 The plan now is to give it a tune up: plugs, check timing, set points (until I can throw a Pamco on it), adjust the valves, change the oil, and the aforementioned carb work. Unless it smokes like a freight train, I'll just ride it as is for as long as possible.
 
 I also noticed the front brake is dragging. I tried to adjust it, but loosening the caliper adjusting screw doesn't change anything. Maybe the pistons need cleaning and brakes bled? They work fine, but seem to be dragging.
 I was able to adjust the rear to work properly.

 This thing may not be as bad as I first thought!