Topic: 76 CB550 long time to "warm up" Timing advance question

[2tall]

Hey guys,

Again, I am new to these bikes and still sorting out what is normal from what is not.

I still haven't synced up my carbs yet, but I got the idle more stable. So that is next on the list. But, I am still having issues with the bike running like it's choked out for the first few minutes. Then all of a sudden, the power is there like a switch is flipped on. Here was my routine tonight:

Started it up after only a few kicks. Ran well enough for me to let it idle while I put my jacket and lid on. I let it warm up while stationary for about 3-4 minutes running at 2500-3000 rpm. The whole time, it sounded like it was choked, but it wasn't. Then, I got on, and started out for my ride. It ran poorly for the first mile to mile and a half, then all of a sudden it all came together. It happened on a down shift, so it was kinda when it got revved up past 5k. After this, it ran perfect.

Is this normal? I'm used to bikes only taking about 2-3 minutes to warm up at idle. Not 10 while riding.

Carbs? Timing? Old age?

Oh yeah, the weather was low 80's and about 80% humidity. ]

Thanks!

Paul

[TwoTired]

It's not normal.  And, your symptoms sound like fuel contamination or the slow jet getting clogged intermittently.  Or, you have a spark plug issue.

When it runs bad you run through the basics first, which means all the tuneup items.  (routine every 3000 miles.)

Check plugs for soot deposits and correct number (heat range).  (A outright bad plug can emulate symptoms you describe.) 

Another clue would be the head pipe temps.  Bikes runs anemic on 3 cylinders and a cool pipe, and much better on all 4.

I don't need a warm up on any of my 550s.  Suit up jump on apply choke start up, back off the choke a little and drive off.  As I ride periodically reach done and bump a little more choke off till it is warm enough to idle on it's own.

I should mention, that my bikes are pretty close to stock configuration.

[martino1972]

i agree....it strongly sounds like your running on 3 cylinders at first......easy to check..."feel" the exhaust pipes....watch it,they can be very hot...!!!!

[Hush]

Pull plugs and see which one is the odd one out, it will be the blackest as it wont have burned all the gas before it finally fires.
Could be as easy as a lose plug cap, when you find the offending plug unscrew the cap and see if it is all green or corroded in there, if so slice off 1/4 inch or less and screw cap back on.
Marti and TT's exhaust check should be done first as it will point you in right direction.

[IHWillys]

i agree....it strongly sounds like your running on 3 cylinders at first......easy to check..."feel" the exhaust pipes....watch it,they can be very hot...!!!!

A little squirt of water on the pipe near the exit from the from the head will readily indicate hot temps vs warm/cool and won't hurt oneself or the bike.

Ken

[Spanner 1]

Whoa 2tall....!!...the points need to open exactly at the 'F' mark, i.e., if using a meter, exactly when the needle drops from it's full reading ( points closed)..this is your 'static' timing mark....the closer you can get 1+4 and 2+3 firing at the F mark, the smoother your motor will be....