Rough deceleration

[joew]

My next item on the list is probably carb related.  The bike doesn't decelerate smoothly.  It kind of burps and stutters making a "blub blub" noise.  Almost like it wants to backfire but not quite that severe. Holding a steady speed it sometimes stutters but acceleration is strong with no issues that I can feel.  Is this a symptom of out of sync carbs? Or do they need to be pulled and cleaned?  Since I do all my on work, I do not really want to pull the carbs out if I can avoid it.

[andyb]

Read the plugs to start.

What mods are done to it?  What's the jetting you currently have?  What altitude/conditions are you riding in?  Does it do this worse when hot or cold?  If you give it a little choke will it still do it?  When was the last carb sync?  Have you tried a different fuel or additive?  Is this a new problem or has it always done this?

Sounds like it's near closed throttle, so pilot circuts, synch, and plugs may all be a good starting point.  Definitely start with a plug read though, particularly the insulator portion near the electrode, after a few minutes of idling/light use.

[joew]

OK, I changed the plugs yesterday.  I kept the old ones and they did have carbon on them - all look to have the same amount.  The plug color chart indicates that they are "carbon fouled" but they aren't as bad as the picture.  Too rich. 

Other info you were looking for:
-Mods - 4 into 1 supertrap exhaust
-I believe stock jetting   
-I am riding mostly at sea level
-Seems a little better when cold
-Not sure about condition when given a little choke
-No idea when (if) carbs were synch'd
-I have not tried different fuel or additive.  Put in regular grade fuel.  Only able to ride it a week ago.  Added half a can of SeaFoam when I got it in November on an almost empty tank.  Ran it then filled it up with gas.  I'm on my second full-up.
-I don't think it is any worse then the first time I rode it.  I was so excited to finally have/ride it that I was not looking close enough for possible issues. 

Since I already changed the plugs I will go ahead and try to sync 'em up using a home made rig and report back.  I don't want to pull em out unless I really have to.  May take a day or two since it's getting cold again.

[SlowOldGuy]

Multiple possibilities, rich and lean.

When mine does that, it is usually a plugged idle jet (from sitting too much).  However, when this happens, the acceleration from idle is really bad since it's essentially missing a cylinder.

Your plugs sound like an overly rich condition so you could be leaking fuel into the intake.  Causes could include bad needle seat o-rings, bad floats, or a bad float/fuel level. 

Or, it could be just a very bad sync.

A carb overhaul on a bike of unknown history is never a bad idea.

DavidR.

[Ratchet_72]

You might also wanna check and see if your exhaust flanges are tight enough.  Cold air leaking back into the chamber does funny things. Probably the carbs though like David says.

[joew]

Resynched the carbs.  BIG difference.  I still need to take everyone's advice and clean them but for now, I am very happy.