Topic: 78 CB550 Surging/bogging issues *HELP PLZ*

[red550]

Hey all, recently purchased a 78 CB550 as a project to fix up over quarantine - bike had been sitting in a basement for approx 34 years and was last registered in 1984 for the road. (had my work cut out for me lol)

My issue seems to be based in the timing but I'm having trouble figuring it out. Every time I seem to get the static timing and points set to a proper place and take it for a good ride, after parking the bike over night/ a couple of days it seems to almost reset to the points/timing being off and back to running like garbage. throttle surging and backfiring at around 3000-4500 rpm and it feels like its bogging when I roll on the throttle and not picking up or responding as it should. 

So far I've cleaned the carbs very thoroughly and done a full carb rebuild, I didn't take them off the rack but replaced all the brass as the original was coated in green varnish from old gas, set the needle to factory and the IMS screws to 1.5 turns out. Replaced the rubber boots on both the air box and engine sides along with the hose clamps that keep them in place. Replaced the air filter with a newer uni foam one but still using the original air box. all new coils (5ohm magna dual output) wires NGK caps and plugs. new condensers and points, new battery and fuses. did the 3000 mile tuneup (bike only has 8600 miles) and vacuum synced the carbs last. Was running ok but its still stuttering and surging around 3000-5000 revs. bike also came with jardine 4-2 pipes rather than the original 4-4s

I will be candid here and say this is my first project bike but I have had a lot of time to research over quarantine (endless youtube vids lol) and also my dad has been giving me some guidance as he has had bikes his whole life and always worked on them - but we are both a little stumped on this one! any help is very welcome !

heres a pic because its pretty and Im proud lol - the tank is off a 77 because the original tank was completely rusted through from the old gas and un-salvageable :^]

Thanks all!

[Maraakate]

You said you replaced all the brass.  Was this genuine OEM Keihen brass?  If it was an aftermarket kit then put the originals back in.  They can be green, but if they aren't plugged they should work OK.  Just get some carb cleaner and spray it in a glass jar and let the jets sit in there over night.  Blow them out with compressed air (but hold the jets in a shop rag so they don't go flying across the room OK?).  If you're using aftermarket float needles this will also cause various issues.

You actually have to reset the points every few days?  What happens?  Is the points gap changing way beyond spec?  Do the timing marks no longer line up?

Replacing the coils was probably unnecessary, but what you have is probably fine.  Same thing with the points and condensors.  As long as the points weren't super pitted they were probably OK.

I also don't recommend changing the air filter unless you plan on rejetting the carbs.  All these various changes you have done to the bike with the air/fuel system will cause all kinds of strange running.  The aftermarket condensors are hit/miss on their quality.  Same thing aftermarket points.

[scottly]

What do your spark plugs look like? Bone white and dry on the porcelain around the center electrode, white and wet, black and wet, or dry sooty black?

[Deltarider]

My issue seems to be based in the timing but I'm having trouble figuring it out. Every time I seem to get the static timing and points set to a proper place and take it for a good ride, after parking the bike over night/ a couple of days it seems to almost reset to the points/timing being off and back to running like garbage. throttle surging and backfiring at around 3000-4500 rpm and it feels like its bogging when I roll on the throttle and not picking up or responding as it should. 

From what you've posted, I'd concentrate on the ignition first. Are you sure what you've adjusted, was tightened well? On the other hand: don't overdo it! From what I read, I cannot rule out parts like breakerpoints or the auxiliary 2+3 plate may have moved somewhat. Visually verify all the little washers AND springwashers are there. Even the Honda pics do not show them all, but they have to be there. Below you'll find a pic that shows them all.
When a bike has sat for that long, I don't know if the advancer still works smoothly. This can be checked with a stroboscopic timing light.
Condensers old enough may have gone bad. Below a vid that shows a bad 1+4 condenser, the 2+3 is OK. A little sparking is OK, arcing like the 1+4 shows, is not.

[bryanj]

Did you remove the pressed in pilot jets? Everything you talk about is typical of pd carbs left for a long time. It is not unheard of, in fact frequently, those carbs have to be cleaned multiple times before working

[red550]

SO bit of an update

I took apart the points plate and the took off the advance plate behind it only to find that there was NO dowel pin holding the plate in place with the camshaft......feeling like a dunce here haha

This was the first time taking the plate off in my defence, I was very surprised to find that it was missing as I figured the previous owner didn't have it off but glad I found that out. I found a replacement pin and put it back together as it should have been and figured that would help with the breaking down but it still seems to be there even with a full readjust of the points gap and static timing.

I took the bike for a spin on the highway this eve and its surging/backfiring after 4500 rpm until about 6000-7000 - at highway speed in 4th gear its struggling to get past 60mph but would eventually get there. not to mention in 5th - was in it for a bit but couldn't keep up with traffic.

any thoughts on this? I'm starting to see an electronic ignition in my future lol and probably another carb teardown / clean ':/

thanks all

[bryanj]

Like i said typical pd carbs

[Deltarider]

SO bit of an update
I took apart the points plate and the took off the advance plate behind it only to find that there was NO dowel pin holding the plate in place with the camshaft.....

Very strange! The advancer is supposed to be one part. See pic below. Is yours the same now? I don't quite understand how your bike could have run at all... Are you sure the heels of the contactbreakers touch the advancer's cam in the right place? I don't rule out irregularities here.
I advice you to go over the ignition again. Please shoot some pics.