smoking from mufflers

Trying to tune my seca with 18,000 miles and ran into this problem. When it's warmed up there is a decent amount of smoke coming out from the mufflers. I just brought valve shims to spec and my compression test numbers were good. I need help diagnosing this issue. Any pointers greatly appreciated.

 

you could have a leaking valve seal it would exspand when your engine is warned up and allow oil down the valve guide into the intake port and then would be sucked into the engine when it is running.

 

I recall your thread regarding compression, & you did have good numbers. So I'm confused now as to where the smoke could be coming from.

Simple check while waiting from others to chime in: You did check engine oil level, correct?

 

What's the "history" on carb service?

Valve stem seals won't affect compression, BTW.

 

What color is the smoke and what were your compression test numbers?

 

The engine oil level was above half of the sight glass before I noticed it smoking. As for the carb history the PO allegedly used a carb kit and reworked the carbs. I haven't touched them at all since I bought the bike because they seemed to be working fine... aside from an occasional stumble in the higher rpm ranges.

I know it has been burning oil however. After an extended ride I will usually have to top it off.

Thanks again.

 

These were the warm compression test numbers. Ill try to see today what color the smoke is.

1 - 148
2 - 138
3 - 135
4 - 142

 

Cylinders #1 and #4 are a bit high for a 550. This would be consistent with excessive oil in the cylinders (kind of like doing a "wet" compression test, but all the time.)

It could also mean that those two cylinders are "dumping" fuel. This could be as simple as inaccurately set floats.

Exactly what oil are you running and what do the plugs look like?

 

I'm running valvoline 10w40 motorcycle oil.

The #1 #2 and #4 spark plugs had slight black and crusty brown deposits on them. (#1 being the worst).

 

Bigfitz, what do you mean by dumping fuel? I interpret that to mean putting so much fuel in that some is overflowing, but then it wouldn't be firing, so I must be reading that wrong. Sounds like something I am just unaware of.

 

Dumping fuel means the carbs are giving too much fuel for the cylinder to burn. Most likley from high float level or needle valve not sealing. The result is excess fuel washing the oil from the cylinder and causing the rings to "score" the cylinder wall. The rings loose their sealing ability and oil bypasses the rings and burns making the visible smoke.
Check your plugs, black and sooty= too much fuel. Balck and oily= bad rings or valve stem seal.

 

UPDATE: Opened up the head last summer and it turned out to be he valve stem seals. Thanks all for your efforts. Cheers!