Topic: And another CB550 not running right...

[thrisco]

Hi everyone! Im new here,  Chris from Northern Virginia...but have been lurking for the past week trying to figure out my problem while learning a ton of great info.
1975 CB550 - UNI pods / 2-1 2-1 exhaust / 40 and 115 jets / 2nd clip from bottom / 1 turn out / timing set and points cleaned and set to .014 / carbs cleaned throughout including emulsion tubes / floats set @ 22mm /bench synced (for now) / compression check seemed kinda low 85 - 80 - 70 - 65 but using a cheap gauge so who knows.

The #3 carb is not right.  There is excessive fuel coming up from the emulsion tube and as I rev the engine, raw fuel sprays out of the intake.  The other carbs do not do this. 

It seems to idle and rev ok with no load (slight sputtering noise from right hand (cyl 3&4) muffler.  Will sputter on acceleration after about 1/4 throttle and never clear up..runs like crap.

What am I missing?  Id rather look like an idiot for missing something simple (which Im hoping it is..)

Thanks for any help guys!

[thrisco]

ok - smaller jets, I have the originals...Ive read elsewhere (trying to figure out this problem) that others were running 115's with no problem.  Regardless, I will put in the original jets. 
Why is it only 1 carb doing this?  I feel like if this carb acted like the others it might run “okayish”..
Bike came from a friend of a friend that has shady history..still had the bag of original carb parts however.

Thanks!  My family lives in Chesterfield. Will update tommorrow.

[scottly]

compression check seemed kinda low 85 - 80 - 70 - 65 but using a cheap gauge so who knows.

The #3 carb is not right.  There is excessive fuel coming up from the emulsion tube and as I rev the engine, raw fuel sprays out of the intake.  The other carbs do not do this. 

It seems to idle and rev ok with no load (slight sputtering noise from right hand (cyl 3&4) muffler.

Take take of the compression issue before trying to tune the carbs.
Have you checked the valve lash adjustments? Too tight valves will bleed off compression, and an intake valve that doesn't close could cause the fuel spitting out of the number 3 carb.

[thrisco]

I did adjust the valves, but think I might need to go back and double check everything.  Thanks for the reply

[thrisco]

Ok so I re-checked the valves which were good.  I swapped out to the original mains which were the 100's.  I put the needle clip 2nd to the bottom to maybe compensate for the lack of 105's.  The bike runs MUCH better but starts to stumble around 5k and up.  I havent had a chance to get new plugs yet to verify whether or not its lean or rich at this point.

[thrisco]

So heres where Im at. 
105's / 2nd from bottom clip / no UNI pod filters = runs great.   
As soon as I put the filter on the #3 carb it sputters, runs great with no filter?  carbs are synchronized.  This seems like its being restricted with air and running too rich but the plug looks normal almost on the lean side of color.  What is going on here?  Has anyone moved needle clips on just one carb?  I cant roll around with 3 filters

[thrisco]

All air screws are equal - everything is equal.  #3 has been a problem from the beginning, and no matter what I do its always the problem.If I rev the engine, you can see a fine mist of fuel at higher rpms coming from the carb like its not being enhaled and just going backwards..

[RAFster122s]

So, any update on your situation after taking advice given?