Light Gray / White Smoke out of Exhaust

[bluhayz]

Hey all,

Thank you for the help in the previous posting. The bike is running fine (bought a new battery - will be swapping out the handlebar probably next weekend.)

I have a new problem now that may be interesting to some. I was riding the bike down Buelah Rd (pretty much at speed 50mph or so) and I made a right onto I want to say telegraph and I had a straight away so I wanted to test out some speed on the bike. I got it to about 9-10k rpms (bike redlines around 14k) and I noticed the bike wasn't really picking up all that much. All of a sudden, there was like a cough, and the bike continued to go however I was then emitting this HUGE cloud of light gray/white smoke.
I know this generally means it's water or coolant however later on I explain why it's a little weirder.

I pulled over, and waited a little, took a look and tried to see if there were any leaks or anything of that nature. It looked fine. I turned it on, and again more smoke. Then I shut it off, I looked at the exhaust and it had some liquid on the end, it had the consistency of oil on the inside of the tailpipe. I then started it again, noticed some smoke, but it seems like it's gone now. I'm wondering if I want to rev it high again to see if that was the cause or if it was something else.

Any ideas? Also, do you all feel like the bike is safe to ride given this course of events or do I have to worry about it being dangerous (with the exception of it really is a smokescreen when this happens).

Thanks,
Drew

[bluhayz]

Haven't heard anything about this and was thinking I may just take it in this weekend to have a real mechanic take a look at it.

I've heard some people tell me it may be the fuel pump (which would probably be an easy fix). The bike does seem like it's running pretty lean and the idle is acting pretty crappy. It turns out the light grey/white smoke only happens when I rev really high under strain to the engine -> so when I'm moving and revving in the 9k-10k range. And it also seems to stick around for awhile in the air so it leads me to believe it's oil and not coolant. I heard coolant dissipates really quickly but this stuff stayed around floating away for awhile.

Any thoughts on the fuel pump idea? I'm probably gonna drop it off a coleman powersports in the next few days just to get the whole bike checked out anyways. I figure while it's their I'll just have them swap out the handlebar too.

Thanks for the help.

[ScottyB]

not alot to contribute but my understanding of smoke color is:

white/sweet smell = coolant
blue tint = oil
black/sooty = rich mixture
gray = lean or burning something off insided the exhaust

i would look into fueling issues if it was me, considering it only seems to happen under high strain and includes loss of power. also, oil burning tends to happen especially during starup or leaving from a stop, so you'd see it then most likely.

[.RJ]

I think you're worrying too much, unless there's something wrong with the way its riding.

Its not a bad idea to do some basic maintenance if you dont have much history on the bike but there's very little chance there's a problem with the fuel pump. I'd change the plugs and clean out the carb jets, shouldnt take more than a few hours.

[bluhayz]

Yeah, I may be worrying too much, but it's a lot of smoke (to put into perspective, it covers the entire width of the lane, and in the distance, it will cover two entire lanes before it dissipates), and I think it affects the riding because it basically limits the bike to a redline of 9k rpms when I would think I should get the full range.

The lack of power is also somewhat confusing and that the smoke only happens when at strain makes me wonder. The spark plugs were swapped out before I bought the bike.

In additional news, the bike is also having difficulty starting where I need to pull the throttle down a little to get it to start the engine. Choke doesn't seem to help/matter at all.

Definitely a quirky bike.

[.RJ]

You sure the plugs were changed? What was put in, OEM or something else? Do you know if the carbs have been touched either? Some jet kits (or an improperly installed jet kit) can have bad effects.

[bluhayz]

I'm checking with the previous owner on all that stuff.

I took off the fuel pump. Before I did that, I tried starting the engine and it didn't seem like the pump was doing anything, no noise, no pulsing or anything. There was no starting to be had.

Is there a way to specifically test the pump? Can I connect like a 12v battery to the ends of the pump and see if it pumps that way? The new fuel pump runs about 170 bucks after taxes are assessed and I don't think I would trust something on ebay (if there even was one on ebay for sale). I hear that these things go out all the time on these types of bikes. And the guy says there was just a nationwide shortage of the fuel pump.

It'd be nice to figure out for sure if it's the fuel pump. Any thoughts?

I'll let you all know what the previous owner comes back with in terms of the carbs and the spark plugs.

[PGK]

It sounds like you have a serious motor issue if it's losing power at high rpm and blowing a lot of smoke.

Step one is to get it started. The fuel pumps on carbed bikes are extremely low pressure, and they generally pulse. if you connect 12v to it it should pump. Remember, green is ground on a Honda.

Once you've got it started, change the oil and filter. Inspect the oil for any debris, if it smells burnt, etc.

Once you've got it started, get it hot, and do a compression test and a leakdown test. These two tests are the basic tests for engine problem diagnosis.


Carb/ignition problem would explain the lack of revs/loss of high-rpm power, but neither would explain the smoke.

[Ginger]

+1

I really don't think your fuel pump is the issue. I've lost the fuel pump several times on my F4, and it never results in smoke. Additionally, as Phil said, the pumps are very low pressure on carbureted motorcycles... it's very unlikely that you're getting enough pressure to run the bike at low rpms, but not at high. You would either have fuel in the bowls at any rpm, or not. Whenever my pump goes out (don't ask) the bike just won't go. Sputters under any kind of load (we're talking 3,000rpm rolling away from stoplights), then won't rev, sputters, dies, and won't restart. No drama. Get the pump going again and all is well with the world.

I'm leaning towards a bigger motor issue, as well. Is it overheating? Check the coolant for oil, and check the oil for milky color. Follow PGK's steps. The smoke is oil... so you've got to find out where that's coming from. It'll likely be the source of all your problems.

[Ginger]

If you're interested in testing the fuel pump, thats a vid of Phil and I doing it on my old VFR ('87 Honda stock). Just hooked the thing up to a 12V car battery, one tube into a half full bottle of beer, the other into another half full bottle of beer. You can hear it pulsing, as carb'd fuel pumps do, and you hear the pulsing speed up as it runs out of fluid to pump.

You likely don't hear the fuel pump on turn key because you've already got sufficient fuel pressure in the lins. They aren't totally dumb, and won't just keep pumping up to infinity. Up to X psi, then they maintain that. If that means that no fluid is actually moving, you won't hear anything.

A better way to test for fuel is to drain the float bowls, close them again, turn the bike on, crank it over. If it starts, you've got a good pump. If it doesn't start, stop, and open the float bowl drain screws again. If fuel comes out, you've got a good fuel pump. If you don't don't jump to the conclusion that the pump is no good. Check for current at it's connector.

[ViPER1313]

I don't know much about bikes, so if this is a stupid thought please correct me.

Could it be that the crankcase is overfilled with oil, and that when the revs got high you experienced a spike in oil pressure / crankcase slosh that made its way into the cylinders and then burned off? How do bikes control crankcase pressure (PCV valve, tube from case to intake?)

[PGK]

I don't know much about bikes, so if this is a stupid thought please correct me.

Could it be that the crankcase is overfilled with oil, and that when the revs got high you experienced a spike in oil pressure / crankcase slosh that made its way into the cylinders and then burned off? How do bikes control crankcase pressure (PCV valve, tube from case to intake?)

Doubtful. Overfilling with oil won't cause an oil pressure spike. Most motorcycle crankcases have enough baffling inside them to prevent major oil slosh, unless you're cranking wheelies and holding them at the balance point for miles, and then it just starves for oil. Breathers are generally connected to the airbox, and on most bikes the also allow oil in the airbox to drain back to the crankcase when the motor isn't running.

Also, if he had a sudden change in oil pressure/slosh whatever, it would have been a one time occurrence, it wouldn't happen every time the bike is revving between 9-10k. Not to mention oil can't really 'slosh' past piston rings. If they can seal 150psi they can definetely keep out enough oil to generate noticeable smoke.

[bluhayz]

wow some very good responses and again I thank you.

I'll test out the fuel pump probably later this afternoon or tomorrow.

The previous owner got back to me. here is what he said:

Yeah, I replaced the spark plugs; I honestly cannot remember what they
are, though. But if you take them out and bring one to a shop they can get
them for you based on whatever it is that's written on the plug. That's
what I did. I myself never touched the carburetor; I'm not incredibly
mechanically inclined. But while I had the bike in the shop over the
winter, they did clean them all out. And yes, it was pricey - I think they
said cleaning the carbs was about 4hrs worth of labor.

So based on that info I can't see it being a plug or carb issue. I was thinking that the bike was running extremely lean so it wouldn't pull as it did when I first got it. now this may be the crazy part, I figured if it was running extremely lean, bringing in a lot of air, and having problems combusting it could create a vacuum in the engine and suck in the oil and cause the smoke?

When it smokes, it last for like, maybe a half a mile. I take it to a place where i can safely stop the bike. wait a little, start it up again, lots of smoke... wait a little while (we're talking maybe 5 minutes), and then start it up again and then it's almost all file. Just a little smoke left but by the time I go back onto the street to go home, it's perfectly fine to get home.

Now of course it's a different story because it won't start. before that started happening, it was having a very bad idle, swaying between 2.5k and 4k and stalling out if it dropped below 2k.

oh, and I looked into the oil and coolant reservoirs and they look fine. so it doesn't look like there is any mixing between them.

[CaptainHenreh]

I'd do a compression test ASAP.

[.RJ]

The oil overfill is a good idea to check - is it too full? that ones easy to do on a bike.

[bluhayz]

hell I don't even know where that is...

[PDenbigh]

It sounds like what my 4 stroke lawnmower does when I get it to too steep of a hill - the cause of which is getting oil into the wrong places. I think checking the oil system is a very good first step.

[.RJ]

The oil overfill is a good idea to check - is it too full? that ones easy to do on a bike.

hell I don't even know where that is...

oh, and I looked into the oil and coolant reservoirs and they look fine

?

[bluhayz]

the oil overfill is just where you put the oil into? I figured you were talking about some special little compartment that I never had to use before.

[.RJ]

the oil overfill is just where you put the oil into? I figured you were talking about some special little compartment that I never had to use before.

Could it be that the crankcase is overfilled with oil

I'll use smaller words...

Is there too much oil in the engine?

There's a window on the side of the motor, below and to the right of where you fill up the oil. Start the bike and let it warm up (if you start it and let it idle for 5 minutes that will do it). Then turn it off and let it sit for 2-3 minutes, and check the oil level - to do this the bike should be upright - NOT on the side stand - and the oil should come up about halfway into the little window. Either hold the bike up while you check or have someone sit on it.

Also, if a shop cleaned/tuned up the carbs over the winter, but then the bike sat for 2 months, you are right back where you started and they are clogged up agin.