Topic: 77 CB550K Cylinders 2/3 not firing

[AngryGreek]

So, I bought my bike all of 2 weeks ago, and already my luck with new toys is starting to show.  I'll try and just do the cliffs notes:

-PO changed oil to 5W30 Synthetic before bringing bike to me
-Bike runs fine for about a day before oil starts leaking out what I assume to be the shifter shaft seal
-Bike starts backfiring into the carbs (cylinders 2/3)
-Change plugs, all 4 were fouled and smelled of Synthetic oil
-After plug change, 2/3 no longer seem to be firing (headers cool to touch at idle)

So this leaves me without my motorcycle and very sad.

I am curious, could it be possible that the (very thin) oil has gotten places oil shouldn't be and messed up my contact breaker?  I'm new to these bikes, and not terribly familiar with what all could cause this. The bike ran fine when I looked at it before purchasing it.

I plan on changing the oil out this weekend to some 20W40 (per reccomendation of Hondaman) but this still leaves me with a not-working bike.

Thanks for your help!

[bryanj]

You are going to have to do a couple of short order oil changes to get rid of the synthetic and i would check the points gap and timing ( and all the rest of the "service" items) tp cure the missfire

[AngryGreek]

Whats the best interval for getting the synthetic out of there?  Change, do 20-30 miles and change again?

Also, going from the manual, Gap is .26, correct?

[garagedoreen]

yeah, check your points. One of the points is for cylinders 1 and 4. The other point is for cylinder 2 and 3. when you look in the site view hole where the points mount on the base, you will see F1.4 to do the timing for cyclinders 1 and 4. And you will see F2.3 to do the timing for cylinders 2 and 3. Check the F2.3 and see if those points are working and on mark. Use a timing light.

hope this helps