Topic: Help cb550 cyliders 1,2 misfire

[Seabass]

Just finished up my bike everything working great.I was riding it daily for a couple weeks.Then on my way home from work my power was cut in half and when I throttle at idle it  feels like it chokes out.Idle circuit is good but somethings up.If it was cylinders 1,4 or2,3 I would assume ignition but cylinders 1,2 are warm but not hot.Next I assumed it was fuel since 1,2 are fed fuel together.I pulled the carbs inpected cleaned.Reinstalled same issue.Anyone had this problem?A little info on the bike.Velocity stacks,electronic ignition,New NGK plug boots, carbs been rebuilt .And the bike has been running great in its current configuration.Thanks guys ,I think Im over thinking it and its something right in front of me.Oh yeah when I pull the plug wire I have spark and when go to put the boot back on it increases my rpm untill I push the boot all the way on it will drop rpm again.

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[crazypj]

What year 550?
There are two fuel inlets to carbs on some, 1-2 & 3-4
1-2 may be blocked or partially blocked. real common when bike is only ever parked on sidestand
Carbs off, cleaning time, do the tank and fuel tap while your at it

[Seabass]

Its a 76 ,Ill check that T again.It was the first place I went to.I blew air through it to make sure it was clear seemed fine.But ill get in there with a brush.

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[Duanob]

Start at the fuel tap. Pull both lines, get a small bowl under the tap and open it up. See if you get good flow from both tubes. then move down the line to the carbs.

[Seabass]

Done n done.

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[Duanob]

Done n done.

And?

[edwardmorris]

real common when bike is only ever parked on sidestand

I wonder if this is why my #1 is always cold when I get it to start. My bike didn't come with a center stand, it has a horrid bobber stand that makes the bike lean at almost 45 degrees. I bought (part of) the center stand from a member here and took the bike off the side stand. Will try and start her up again to see if it helped. I guess I'll have to clean the carbs first though...

[crazypj]

You do turn the gas off about 3/4 mile before stopping ?
#1 can flood if bike leans over far enough, I think the fuel in line and between 1&2 does it?

[Seabass]

Im still hunting for the problem.I drained all the gas from the tank so I can start with fresh fuel.Also to remove some mystery oil that I added to the gas before the issue.Never had a problem with mystery oil before but its the only thing I did to the bike before the problem occured.Ive gone through the fuel system from petcock down.When I get home from work tonight Ill get the carbs back on and see if anything changed.I have not tried the turning the gas off 3/4 mile before parking.I have a piece of two by four that I useally put under the kickstand but only at home.

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[Seabass]

Thanks for the help. I was able to figure  out the mystery "pun intended". After draining the gas and changing the oil soaked spark plugs  the bike runs great now. I went a little heavy with the marvel mystery oil and it looks like it was causing  the gas to not fire well and leaving the oil behind in my cylinders. I've always had a hard time following  directions. Next time I'll leave the mystery  oil in the oil.

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