Clouds of smoke!

[Thors]

Figure we can play a little guessing game with this.

2005 Pitbull Stock Motor changed over to S&S rocker boxes around 5000 miles. 23000 or so on it now. Bike runs great. Strong, smooth, and no strange noises. Riding the other day and roll onto the throttle slowly in 2nd. Starts to accel normally then the engine sound changes drastically to an almost pingy misfiring sound and it has no pick up. Let off then blip it and sounds fine. Get back on it and no prob. That's when I notice the CLOUDS of smoke in my rear view. Didn't keep smoking, only during the strange sound/lack of power. Checked oil, tappet screen, etc.. when home and nothing strange. This has now happened three times, same symptoms and scenario. Not just a little smoke, lots! Other than these "episodes" the bike doesn't smoke at all.

Compression tested ~165/160 front and back. Plugs were looking fine, now they are showing signs of light oil fouling. I'll be pulling the heads soon and am probably done riding for the season. Anyone have an idea of what I may find?? The intermittent nature has me a bit stumped. That along with how good the dam things running...hate to tear it down but don't want to nuke my motor.

 

[Little-Boo]

Have you checked your air cleaner to see if there is oil in there. Could be that your check valve (coming from the rear head) is shot and blowing oil into the carb. Did you make a right turn when this happened ?. Sometimes oil puddles in the heads and when you make a right turn some oil seeps by the valve oil seals if they are worn and caused the bike to smoke then it goes away. If the rings were bad, it would smoke all the time. I would replace the valve oil seals and keep on riding.

Carlos

 

[Thors]

Hi Carlos.
I knew I'd forget a detail or 2. Running S&S dual runners and head breather isn't connected. Wasn't turning. Valve seals sound like a good culprit. The noise is what worries me though...it's almost metallic rattle/rappy. I'm wondering if I'm gonna find valve guides that are absolutely shot. Hopefully know by the end of the weekend...

 

[Raywood]

Compression is real low for your motor. Did you disconnect the CRs when you performed the test? Mine at 95000 miles still pushed 190 psi

 

[Thors]

Nope left them working and still got that so I didn't worry. Was mainly looking for consistency between cylinders. Once I start pulling it apart I'll retest. Can't get to CR wiring as it sits...

Does that fact that this is an EPA motor build factor into the lower compression? That will be rectified during this fix.

 

[Sven]

Starts to accel normally then the engine sound changes drastically to an almost pingy misfiring sound and it has no pick up.

Lots of oil will det... lots of heat... There is a certain fuel to oil ratio like a 2-stroke uses, but we see bellows of oil out the exhaust as you describe...

That's when I notice the CLOUDS of smoke in my rear view. Didn't keep smoking, only during the strange sound/lack of power.

... look at how the oil firing off is lack of power being shown, change in note, ping at play.

happened three times, same symptoms and scenario. Not just a little smoke, lots!

And it only happens when you wind the engine up, correct?

Other than these "episodes" the bike doesn't smoke at all.

So it goes something like this:
1. I wind up my engine, one set of rings relax as the other is under compression. The power piston is on its way down; creates crankcase pressure; the vent is too narrow for this type of high rpm; but fine when at putt-putt pace.
2. I start the bike in the morning, no puff of smoke as to think the guides are worn; and so would be the guide seals, but say yes or no... you make no mention of excess oil upon startup, so no is the guess of no puffs at cold start.
3. I would have to conclude that the low psi of 160 with 23k miles and someone with 190 psi with 10k miles may have nothing to do with emissions, but this oil escape that cannot keep the oil under the rings is possible excessive ring end gap due to low compression.

now they are showing signs of light oil fouling.

Can't be:
a. Broken rings = Only smokes when getting on it.
b. Guide seals = Does not smoke upon start up.
c. Guides = Does not smoke when I lift off the gas, get back on it, no puff visible.... try that... yes or no?
d. Compression = Smells like?
e. Breather system backed up = Looks like?
f. Fukiff I know?

 

[Thors]

Good stuff Sven.
It does not smoke on startup. What I find strange is the intermittent nature of the smoke/loss of power. I can ride for 30 miles, cranking away on the throttle and the issue doesn't happen. Then I go to take off slow...once was from a stop light...as I hit second and gently rolled into it all of sudden power loss and clouds of smoke. Then another bunch of miles with no issues and plenty of heavy throttle use. WTF is getting out of wack for a moment...then going back to normal? We shall see I hope.

 

[firedog19]

What color is the smoke?

 

[Thors]

Blue. Lots and lots of blue smoke. Then back to smooth running. By the plug it appears to be the front cylinder. I'll get into it this weekend...

 

[bdmridgeback]

Valve guides are gone. 100% on that one. You probably notice if you cruise for a bit, make a left turn, straighten bike up and roll on the throttle hard it blows smoke for about 10 sec or so. Valve guides!

Sent from my SM-G925P using Tapatalk

 

[Thors]

Sounds right. Time will tell. Haven't been riding or wrenching, too busy with work!

Thanks for the replies. I'll post back once I tear it down.

 

[Mastiff Rider64]

Mines been doing the same thing. I can hit the interstate running 90 mph and nothing. Get off at first exit make my turn and boom smoke screen everyone behind me even the state trooper. lol. I had my bike switched from the TP heads to S&S 3 years ago and this started last year, but I only caught it doing it once or twice have made it thru this riding season too. But noticed its getting worse. If I sit at a red light to long now mine will puff smoke lightly then when I go to take of smoke the whole 4 lanes up. But I hear the pinging and rattles when I roll on my throttle going down the interstate. For the longest time I thought my gas tank was hitting metal somewhere on the bike. But I've been told that I smashed a valve guide seal from what the mechanic called free wheeling or something?

 

[Thors]

Well at least I'm not the only one! I have been out a couple times with no smoke. Dam clutch hub nut came loose again...fixed but need the new hardened nut...so that's on the list for this winter. Dying to tear into it but don't want to be bikeless for the remaining nice days. This is why a minimum of 2 bikes should be in all garages!

 

[john sachs]

5,000 miles with TP rocker bxes is enough to get the valve guide ball rolling. Look at the valve stem tips, and see where the rocker arms have left their mark.
Also, can be the breather system. Breathe it out the rear o the case with a black & white one way valve, and see if that makes a difference.
Be sure the oil tank isn't overfilled, and the breather bore isn't scored.
John

 

[francoblay1]

5,000 miles with TP rocker bxes is enough to get the valve guide ball rolling. Look at the valve stem tips, and see where the rocker arms have left their mark.
Also, can be the breather system. Breathe it out the rear o the case with a black & white one way valve, and see if that makes a difference.
Be sure the oil tank isn't overfilled, and the breather bore isn't scored.
John

Should I post my pics again? they had about 1K miles only... thank God I done the change to S&S.