Hey all...my '76 CB550 is misbehaving still
its been a few 2 weeks since i "completed" my build and have ridden it on 3 occasions but not without teething issues.
First was an oil leak followed by rough running while in gear at low rpm (at higher rpm there is absolutely no problems)
so i fixed the leak and now its just the rich scenario.
This is what iv done so far...
-I rebuilt the carbs replacing every o-ring. the main jets, slow jets, needle and seat and emulsion tubes were cleaned thoroughly. float heights were set at 22mm with the float tab just resting on the needle without pressing the needle in. The needle jets clip position is on number two from top. the carbs were soda blasted and cleaned out thoroughly too. Bench synch'd very accurately although the bottom of my slides are not all perfectly flat, some have small wear marks making them slightly larger, but she idles perfectly, the motor is quiet and revs up very smoothly. My air screws are out close to 3 turns to lean out the very rich mix. My mate said when i blasted past him he though i had blown my motor from the rich smoke coming out the zhorst. I have also been having problems with cylinder 4 where it is missing from time to time when i cold start her after a few days, it has carbon build up and works after i clean it, so i assume there is something wrong with the 4th carb? reason i know, header 4 is cold when others are hot after a minute of idling.
my
airbox is a custom one: i have tried my best to get the surface area of the opening to match the original with the space the mesh takes up. the filter material i used, if anything will let more air through than stock, so it cant be the reason for running rich? i have also removed the filter completely to see whether if it could have been restricting airflow...no change.
My
exhaust is an aftermarket one, loud too, so i assume its got very little baffling.
this is what the inside looks like. ignore the rough edges, its not the final product.
My tappets are adjusted to spec, the cam chain is tensioned, I have new spark plugs, new plug caps too.
The other thing i have not really fiddled with is the ignition timing until today. Both honda and clymer manuals are not so easy to understand when it comes to point gaps.
-I basically need to rotate the crankshaft until the points for 1.4 are fully open, makes no difference where timing marks are, correct? then do the same for the 2.3? and use 0.3 or 0.4mm feeler gauge to set the gaps...
The Clymer not only says that the gauge you should use is 0.04mm, but also that when points 1.4 are fully open the index marks 1.4 must line up with fire mark? its contradicting to me... at the index mark and fire mark for either 1.4 or 2.3 the points contacts are closed....not fully open...
-after reading up a bit, TwoTired mentions that one should eliminate all lateral and vertical movements of the points plate by putting a feeler gauge between the plate and the case at one of the 3 screw mounting points, correct? this should actually be done before the point gaps are set to prevent any movements what setting ignition timing later on?
like this? The plate after the feeler gauge (red strip) will push the plate towards the other mounting points in the direction of the arrows:
once that is done, then there are different methods of setting the ignition timing, either strobe, or bulb methods? i dont want to get too far into that for now, as i have not fiddled with that part yet.
Does anyone have an idea as to what can be causing my problems? im at wits end
here are some pics of said bike:
so i ask you again, why would i get the major jerking and stumbling on acceleration at nearly no throttle until i open the throttle past say 1/4 throttle, then she flies! she sometimes kind of spits out the exhaust, like a misfire sound, can also be heard from the airbox on occasion.
